www.youtube.com/watch?v=7gpjJUbPfzY&feature=related

www.youtube.com/watch?v=_1UEXBXNyyQ&feature=related

 

www.crystalinks.com/chakras.html

 

In Hinduism and its spiritual systems of yoga and in some related eastern cultures, as well as in some segments of the New Age movement -- and to some degree the distinctly different New Thought movement - a chakra is thought to be an energy node in the human body.

 

The word comes from the Sanskrit "cakra" meaning "wheel, circle", and sometimes also referring to the "wheel of life". The pronunciation of this word can be approximated in English by 'chuhkruh', with ch as in chart and both instances - the commonly found pronunciation 'shockrah' is incorrect.

 

The seven main chakras are described as being aligned in an ascending column from the base of the spine to the top of the head. Each chakra is associated with a certain color, multiple specific functions, an aspect of consciousness, a classical element, and other distinguishing characteristics.

 

The chakras are thought to vitalise the physical body and to be associated with interactions of both a physical and mental nature. They are considered loci of life energy, or prana, which is thought to flow among them along pathways called nadis.

  

In Mysticism, a Nadi (plural: Nadis) is an energy channel in which prana energy flows and may connect chakras. It is not accepted by mainstream science. The main nadis include Shushumna, Ida and Pingala.

Nadis are thought to carry a life force energy known as prana in Sanskrit, or qi in Chinese-based systems. They are also said to have an extrasensory function, playing a part in empathic and instinctive responses.Nadis are sometimes viewed as extending only to the skin of the body, but are often thought to extend to the boundary of the aura.

 

The Ida and Pingala nadis are often seen as referring to the two hemispheres of the brain. Pingala is the extroverted, solar nadi, and corresponds to the left hand side of the brain. Ida is the introverted, lunar nadi, and refers to the right hand side of the brain.

 

The two nadis are stimulated through the practice of pranayama, which involves alternate breathing through left and right nostrils, which would alternately stimulate the left and right sides of the brain.The word nadi comes from the Sanskrit root nad meaning "channel", "stream", or "flow".

  

Traditional Chinese medicine also relies on a similar model of the human body as an energy system.

 

The New Age movement has led to an increased interest in the West regarding chakras. Many in this movement point to a correspondence between the position and role of the Chakras, and those of the glands in the endocrine system. Some people in New Age also claim that other chakras, besides the above, exist - for instance, ear chakras.

 

The chakras are described in the tantric texts the Sat-Cakra-Nirupana, and the Padaka-Pancaka, in which they are described as emanations of consciousness from Brahman, an energy which comes down from the spiritual and gradually crudifies, creating these distinct levels of chakras, and which eventually finds its rest in the Muladhara chakra.

  

Muladhara is positioned close to anus, at the perineum, and it has four petals which match the vrittis of greatest joy, natural pleasure, delight in controlling passion, and blissfulness in concentration.

In Samkhya philosophy, the concept of Muladhara is that of moola prakriti, the metaphysical basis of material existence. Muladhara is the chakra that draws down spritual energy and causes it to assume a physical existence. It is like the negative pole in an electrical circuit, which provides the potential for the evolution of form.

 

Within this chakra resides sleeps the kundalini shakti, the great spiritual potential, waiting to be aroused and brought back up to the source from which it originated, Brahman.

 

Muladhara is the base from which the 3 main psychic channels, nadis, ida, pingala and sushumna, emerge.It is related to the physical processes of reproduction and excretion, and also to the various fear and guilt complexes associated with them. All a person's Samskaras ( potential karma ), are expressed here, in a physical form.

 

This chakra is associated with the deities Indra, Brahma and Dakini, the element Earth and the color red.

  

They are therefore part of an emanationist theory, like that of the kabbalah in the west, or neo-platonism. The energy that was unleashed in creation, called the Kundalini, lies coiled and sleeping, and it is the purpose of a tantric yogi to arouse this energy, and cause it to rise back up through the increasingly subtler chakras, until union with god is achieved in the Sahasrara chakra at the crown of the head.

  

Sahasrara is positioned above the head or at the top of it and it has 1000 petals which are arranged in 20 layers each of them with 50 petals. For a discussion about the petal count see also petal (chakra)Often referred as thousand-petaled lotus, it is said to be the most subtle chakra in the system, relating to pure consciousness, and it is from this chakra that all the other chakras emanate. When a yogi is able to raise his or her kundalini, energy of consciousness, up to this point, the state of samadhi, or union with god, is experienced.

 

Apart from this primary text from India, different western authors have tried to describe the chakras, most notably the Theosophists. Many new age writers, such as the Danish author and musician Peter Kjaerulff in his book, The Ringbearers Diary, or Anodea Judith in her book Wheels of Life, have written their opinions about the chakras in great detail, including the reasons for their appearance and their functions.

 

The seven chakras are said by some to reflect how the unified consciousness of man (the immortal human being or the soul), is divided to manage different aspects of earthly life (body/instinct/vital energy/deeper emotions/communication/having an overview of life/contact to God). The chakras are placed at differing levels of spiritual subtletly, with Sahasrara at the top being concerned with pure consciousness, and Muladhara at the bottom being concerned with matter, which is seen simply as crudified consciousness.

  

www.lichtkreis.at/html/Wissenswelten/Chakren/sieben-haupt...

 

Die sieben Hauptchakren

Kronenchakra, Stirnchakra, Halschakra, Herzchakra, Solarplexuschakra, Sakralchakra und Wurzelchakra

Layouthilfe

Den Chakren werden unterschiedliche universelle Qualitäten des menschlichen Lebens zugeordnet. Aus diesen Qualitäten lassen sich wiederum subjektiv positive und negative Ausdrucksformen ableiten.

 

Es werden im Allgemeinen sieben Hauptchakren unterschieden. Jedes Chakra schwingt in einer seiner Aufgabe entsprechenden Grundfarbe und steht mit bestimmten Organen und Körperbereichen in Verbindung. Die sieben Hauptchakren entsprechen darüber hinaus den sieben Hauptdrüsen des endokrinen Systems (das Endokrine System ist die Gesamtheit aller Hormonbildenden Organe und Zellen). Auch steuert jedes Chakra einen spezifischen Aspekt des menschlichen Verhaltens und der menschlichen Entwicklung und wird seinerseits davon geprägt. Die unteren Chakras, deren Energien langsamer schwingen, stehen mit den Grundbedürfnissen und Emotionen des Menschen in Verbindung. Die feineren Energien der oberen Chakras entsprechen den höheren geistigen und spirituellen Bestrebungen und Fähigkeiten des Menschen.

 

Die Chakren haben ihren Namensursprung im Sanskrit, und haben in der deutschen Übersetzung teils unterschiedliche Bezeichnungen erhalten. Um dir einen Überblick der gebräuchlichsten Bezeichnungen zu geben haben wir diese in der folgenden Tabelle zusammengefasst. Dies soll dir die Zuordnung erleichtern, da du sie vielleicht unter dem einen oder anderen Namen kennst. Wir nutzen in unseren Texten die fett hervorgehobenen Namen.

 

Sanskrit Deutsch

1 Mūlādhāra

(Wurzelstütze) Wurzelchakra, Basischakra, Wurzelzentrum, Basiszentrum, 1. Chakra

2 Svādhisthāna

(Süße, Liebliche) Sakralchakra, Sexualchakra, Kreuz-Zentrum, Polaritätschakra, Sexualzentrum, 2.Chakra

3 Manipūra

(Leuchtender Juwel) Solarplexuschakra, Nabelchakra, Nabelzentrum,

Milzchakra, Magenchakra, 3. Chakra

4 Anāhata

(Unbeschädigte) Herzchakra, Herzzentrum, 4. Chakra

5 Viśuddha

(Reinigende) Halschakra, Kehlchakra, Kommunikationszentrum, 5. Chakra

6 Ājñā

(Wahrnehmende) Stirnchakra, Drittes Auge, Inneres Auge, Stirnzentrum, 6. Chakra

7 Sahasrāra

(Tausendfache) Kronenchakra, Scheitelchakra, Scheitelzentrum, 7. Chakra

 

Das erste Chakra, das Wurzelchakra, befindet sich zwischen Anus und Genitalien. Das zweite Chakra, das Sakralchakra, befindet sich etwa eine Handbreit unter dem Bauchnabel, das dritte Chakra, das Solarplexuschakra, liegt direkt über dem Sonnengeflecht etwas in Höhe des Magens. Es ist ein zentraler Knotenpunkt der Nervensysteme des Körpers. Das vierte Chakra ist das Herzchakra; es liegt in Höhe des Herzens. Das Fünfte ist das Halschakra, und das sechste das Stirnchakra, welches sich zwischen den Augenbrauen befindet. Einige Zentimeter über dem Scheitelpunkt des Kopfes sitzt das Kronenchakra.

 

Die Öffnungen der Chakren befinden sich jeweils an der Vorder- und an der Rückseite des Körpers mit Ausnahme des Wurzel- und des Kronenchakra, welche nach unten bzw. oben geöffnet sind.

 

Den Chakren werden auch unterschiedliche universelle Qualitäten des menschlichen Lebens zugeordnet. Aus diesen Qualitäten lassen sich wiederum positive und negative Ausdrucksformen ableiten. Wie Wissen (steht für Kronenchakra), Wahrnehmung (Stirnchakra), Ausdruck (Halschakra), Beziehung, Liebe (Herzchakra), Wille, Macht (Solarplexuschakra), Sexualität, Gefühle (Sakralchakra) und Überleben, Instinkte (Wurzelchakra)

 

Mit Hilfe verschiedener Techniken (z.B.: Reiki, Kinesiologie, Schwingungsübertragung, Mudra) werden sie positiv beeinflusst um eine Harmonie zwischen dem geistigen Leib, der "Lebensenergie", und dem körperlichen Leib herzustellen.

   

Fish, any of approximately 34,000 species of vertebrate animals (phylum Chordata) found in the fresh and salt waters of the world. Living species range from the primitive jawless lampreys and hagfishes through the cartilaginous sharks, skates, and rays to the abundant and diverse bony fishes. Most fish species are cold-blooded; however, one species, the opah (Lampris guttatus), is warm-blooded.

 

The term fish is applied to a variety of vertebrates of several evolutionary lines. It describes a life-form rather than a taxonomic group. As members of the phylum Chordata, fish share certain features with other vertebrates. These features are gill slits at some point in the life cycle, a notochord, or skeletal supporting rod, a dorsal hollow nerve cord, and a tail. Living fishes represent some five classes, which are as distinct from one another as are the four classes of familiar air-breathing animals—amphibians, reptiles, birds, and mammals. For example, the jawless fishes (Agnatha) have gills in pouches and lack limb girdles. Extant agnathans are the lampreys and the hagfishes. As the name implies, the skeletons of fishes of the class Chondrichthyes (from chondr, “cartilage,” and ichthyes, “fish”) are made entirely of cartilage. Modern fish of this class lack a swim bladder, and their scales and teeth are made up of the same placoid material. Sharks, skates, and rays are examples of cartilaginous fishes. The bony fishes are by far the largest class. Examples range from the tiny seahorse to the 450-kg (1,000-pound) blue marlin, from the flattened soles and flounders to the boxy puffers and ocean sunfishes. Unlike the scales of the cartilaginous fishes, those of bony fishes, when present, grow throughout life and are made up of thin overlapping plates of bone. Bony fishes also have an operculum that covers the gill slits.

 

The study of fishes, the science of ichthyology, is of broad importance. Fishes are of interest to humans for many reasons, the most important being their relationship with and dependence on the environment. A more obvious reason for interest in fishes is their role as a moderate but important part of the world’s food supply. This resource, once thought unlimited, is now realized to be finite and in delicate balance with the biological, chemical, and physical factors of the aquatic environment. Overfishing, pollution, and alteration of the environment are the chief enemies of proper fisheries management, both in fresh waters and in the ocean. (For a detailed discussion of the technology and economics of fisheries, see commercial fishing.) Another practical reason for studying fishes is their use in disease control. As predators on mosquito larvae, they help curb malaria and other mosquito-borne diseases.

 

Fishes are valuable laboratory animals in many aspects of medical and biological research. For example, the readiness of many fishes to acclimate to captivity has allowed biologists to study behaviour, physiology, and even ecology under relatively natural conditions. Fishes have been especially important in the study of animal behaviour, where research on fishes has provided a broad base for the understanding of the more flexible behaviour of the higher vertebrates. The zebra fish is used as a model in studies of gene expression.

 

There are aesthetic and recreational reasons for an interest in fishes. Millions of people keep live fishes in home aquariums for the simple pleasure of observing the beauty and behaviour of animals otherwise unfamiliar to them. Aquarium fishes provide a personal challenge to many aquarists, allowing them to test their ability to keep a small section of the natural environment in their homes. Sportfishing is another way of enjoying the natural environment, also indulged in by millions of people every year. Interest in aquarium fishes and sportfishing supports multimillion-dollar industries throughout the world.

 

Fishes have been in existence for more than 450 million years, during which time they have evolved repeatedly to fit into almost every conceivable type of aquatic habitat. In a sense, land vertebrates are simply highly modified fishes: when fishes colonized the land habitat, they became tetrapod (four-legged) land vertebrates. The popular conception of a fish as a slippery, streamlined aquatic animal that possesses fins and breathes by gills applies to many fishes, but far more fishes deviate from that conception than conform to it. For example, the body is elongate in many forms and greatly shortened in others; the body is flattened in some (principally in bottom-dwelling fishes) and laterally compressed in many others; the fins may be elaborately extended, forming intricate shapes, or they may be reduced or even lost; and the positions of the mouth, eyes, nostrils, and gill openings vary widely. Air breathers have appeared in several evolutionary lines.

 

Many fishes are cryptically coloured and shaped, closely matching their respective environments; others are among the most brilliantly coloured of all organisms, with a wide range of hues, often of striking intensity, on a single individual. The brilliance of pigments may be enhanced by the surface structure of the fish, so that it almost seems to glow. A number of unrelated fishes have actual light-producing organs. Many fishes are able to alter their coloration—some for the purpose of camouflage, others for the enhancement of behavioral signals.

 

Fishes range in adult length from less than 10 mm (0.4 inch) to more than 20 metres (60 feet) and in weight from about 1.5 grams (less than 0.06 ounce) to many thousands of kilograms. Some live in shallow thermal springs at temperatures slightly above 42 °C (100 °F), others in cold Arctic seas a few degrees below 0 °C (32 °F) or in cold deep waters more than 4,000 metres (13,100 feet) beneath the ocean surface. The structural and, especially, the physiological adaptations for life at such extremes are relatively poorly known and provide the scientifically curious with great incentive for study.

 

Almost all natural bodies of water bear fish life, the exceptions being very hot thermal ponds and extremely salt-alkaline lakes, such as the Dead Sea in Asia and the Great Salt Lake in North America. The present distribution of fishes is a result of the geological history and development of Earth as well as the ability of fishes to undergo evolutionary change and to adapt to the available habitats. Fishes may be seen to be distributed according to habitat and according to geographical area. Major habitat differences are marine and freshwater. For the most part, the fishes in a marine habitat differ from those in a freshwater habitat, even in adjacent areas, but some, such as the salmon, migrate from one to the other. The freshwater habitats may be seen to be of many kinds. Fishes found in mountain torrents, Arctic lakes, tropical lakes, temperate streams, and tropical rivers will all differ from each other, both in obvious gross structure and in physiological attributes. Even in closely adjacent habitats where, for example, a tropical mountain torrent enters a lowland stream, the fish fauna will differ. The marine habitats can be divided into deep ocean floors (benthic), mid-water oceanic (bathypelagic), surface oceanic (pelagic), rocky coast, sandy coast, muddy shores, bays, estuaries, and others. Also, for example, rocky coastal shores in tropical and temperate regions will have different fish faunas, even when such habitats occur along the same coastline.

 

Although much is known about the present geographical distribution of fishes, far less is known about how that distribution came about. Many parts of the fish fauna of the fresh waters of North America and Eurasia are related and undoubtedly have a common origin. The faunas of Africa and South America are related, extremely old, and probably an expression of the drifting apart of the two continents. The fauna of southern Asia is related to that of Central Asia, and some of it appears to have entered Africa. The extremely large shore-fish faunas of the Indian and tropical Pacific oceans comprise a related complex, but the tropical shore fauna of the Atlantic, although containing Indo-Pacific components, is relatively limited and probably younger. The Arctic and Antarctic marine faunas are quite different from each other. The shore fauna of the North Pacific is quite distinct, and that of the North Atlantic more limited and probably younger. Pelagic oceanic fishes, especially those in deep waters, are similar the world over, showing little geographical isolation in terms of family groups. The deep oceanic habitat is very much the same throughout the world, but species differences do exist, showing geographical areas determined by oceanic currents and water masses.

 

All aspects of the life of a fish are closely correlated with adaptation to the total environment, physical, chemical, and biological. In studies, all the interdependent aspects of fish, such as behaviour, locomotion, reproduction, and physical and physiological characteristics, must be taken into account.

 

Correlated with their adaptation to an extremely wide variety of habitats is the extremely wide variety of life cycles that fishes display. The great majority hatch from relatively small eggs a few days to several weeks or more after the eggs are scattered in the water. Newly hatched young are still partially undeveloped and are called larvae until body structures such as fins, skeleton, and some organs are fully formed. Larval life is often very short, usually less than a few weeks, but it can be very long, some lampreys continuing as larvae for at least five years. Young and larval fishes, before reaching sexual maturity, must grow considerably, and their small size and other factors often dictate that they live in a habitat different than that of the adults. For example, most tropical marine shore fishes have pelagic larvae. Larval food also is different, and larval fishes often live in shallow waters, where they may be less exposed to predators.

 

After a fish reaches adult size, the length of its life is subject to many factors, such as innate rates of aging, predation pressure, and the nature of the local climate. The longevity of a species in the protected environment of an aquarium may have nothing to do with how long members of that species live in the wild. Many small fishes live only one to three years at the most. In some species, however, individuals may live as long as 10 or 20 or even 100 years.

 

Fish behaviour is a complicated and varied subject. As in almost all animals with a central nervous system, the nature of a response of an individual fish to stimuli from its environment depends upon the inherited characteristics of its nervous system, on what it has learned from past experience, and on the nature of the stimuli. Compared with the variety of human responses, however, that of a fish is stereotyped, not subject to much modification by “thought” or learning, and investigators must guard against anthropomorphic interpretations of fish behaviour.

 

Fishes perceive the world around them by the usual senses of sight, smell, hearing, touch, and taste and by special lateral line water-current detectors. In the few fishes that generate electric fields, a process that might best be called electrolocation aids in perception. One or another of these senses often is emphasized at the expense of others, depending upon the fish’s other adaptations. In fishes with large eyes, the sense of smell may be reduced; others, with small eyes, hunt and feed primarily by smell (such as some eels).

 

Specialized behaviour is primarily concerned with the three most important activities in the fish’s life: feeding, reproduction, and escape from enemies. Schooling behaviour of sardines on the high seas, for instance, is largely a protective device to avoid enemies, but it is also associated with and modified by their breeding and feeding requirements. Predatory fishes are often solitary, lying in wait to dart suddenly after their prey, a kind of locomotion impossible for beaked parrot fishes, which feed on coral, swimming in small groups from one coral head to the next. In addition, some predatory fishes that inhabit pelagic environments, such as tunas, often school.

 

Sleep in fishes, all of which lack true eyelids, consists of a seemingly listless state in which the fish maintains its balance but moves slowly. If attacked or disturbed, most can dart away. A few kinds of fishes lie on the bottom to sleep. Most catfishes, some loaches, and some eels and electric fishes are strictly nocturnal, being active and hunting for food during the night and retiring during the day to holes, thick vegetation, or other protective parts of the environment.

 

Communication between members of a species or between members of two or more species often is extremely important, especially in breeding behaviour (see below Reproduction). The mode of communication may be visual, as between the small so-called cleaner fish and a large fish of a very different species. The larger fish often allows the cleaner to enter its mouth to remove gill parasites. The cleaner is recognized by its distinctive colour and actions and therefore is not eaten, even if the larger fish is normally a predator. Communication is often chemical, signals being sent by specific chemicals called pheromones.

 

Many fishes have a streamlined body and swim freely in open water. Fish locomotion is closely correlated with habitat and ecological niche (the general position of the animal to its environment).

 

Many fishes in both marine and fresh waters swim at the surface and have mouths adapted to feed best (and sometimes only) at the surface. Often such fishes are long and slender, able to dart at surface insects or at other surface fishes and in turn to dart away from predators; needlefishes, halfbeaks, and topminnows (such as killifish and mosquito fish) are good examples. Oceanic flying fishes escape their predators by gathering speed above the water surface, with the lower lobe of the tail providing thrust in the water. They then glide hundreds of yards on enlarged, winglike pectoral and pelvic fins. South American freshwater flying fishes escape their enemies by jumping and propelling their strongly keeled bodies out of the water.

 

So-called mid-water swimmers, the most common type of fish, are of many kinds and live in many habitats. The powerful fusiform tunas and the trouts, for example, are adapted for strong, fast swimming, the tunas to capture prey speedily in the open ocean and the trouts to cope with the swift currents of streams and rivers. The trout body form is well adapted to many habitats. Fishes that live in relatively quiet waters such as bays or lake shores or slow rivers usually are not strong, fast swimmers but are capable of short, quick bursts of speed to escape a predator. Many of these fishes have their sides flattened, examples being the sunfish and the freshwater angelfish of aquarists. Fish associated with the bottom or substrate usually are slow swimmers. Open-water plankton-feeding fishes almost always remain fusiform and are capable of rapid, strong movement (for example, sardines and herrings of the open ocean and also many small minnows of streams and lakes).

 

Bottom-living fishes are of many kinds and have undergone many types of modification of their body shape and swimming habits. Rays, which evolved from strong-swimming mid-water sharks, usually stay close to the bottom and move by undulating their large pectoral fins. Flounders live in a similar habitat and move over the bottom by undulating the entire body. Many bottom fishes dart from place to place, resting on the bottom between movements, a motion common in gobies. One goby relative, the mudskipper, has taken to living at the edge of pools along the shore of muddy mangrove swamps. It escapes its enemies by flipping rapidly over the mud, out of the water. Some catfishes, synbranchid eels, the so-called climbing perch, and a few other fishes venture out over damp ground to find more promising waters than those that they left. They move by wriggling their bodies, sometimes using strong pectoral fins; most have accessory air-breathing organs. Many bottom-dwelling fishes live in mud holes or rocky crevices. Marine eels and gobies commonly are found in such habitats and for the most part venture far beyond their cavelike homes. Some bottom dwellers, such as the clingfishes (Gobiesocidae), have developed powerful adhesive disks that enable them to remain in place on the substrate in areas such as rocky coasts, where the action of the waves is great.

 

The methods of reproduction in fishes are varied, but most fishes lay a large number of small eggs, fertilized and scattered outside of the body. The eggs of pelagic fishes usually remain suspended in the open water. Many shore and freshwater fishes lay eggs on the bottom or among plants. Some have adhesive eggs. The mortality of the young and especially of the eggs is very high, and often only a few individuals grow to maturity out of hundreds, thousands, and in some cases millions of eggs laid.

 

Males produce sperm, usually as a milky white substance called milt, in two (sometimes one) testes within the body cavity. In bony fishes a sperm duct leads from each testis to a urogenital opening behind the vent or anus. In sharks and rays and in cyclostomes the duct leads to a cloaca. Sometimes the pelvic fins are modified to help transmit the milt to the eggs at the female’s vent or on the substrate where the female has placed them. Sometimes accessory organs are used to fertilize females internally—for example, the claspers of many sharks and rays.

 

In the females the eggs are formed in two ovaries (sometimes only one) and pass through the ovaries to the urogenital opening and to the outside. In some fishes the eggs are fertilized internally but are shed before development takes place. Members of about a dozen families each of bony fishes (teleosts) and sharks bear live young. Many skates and rays also bear live young. In some bony fishes the eggs simply develop within the female, the young emerging when the eggs hatch (ovoviviparous). Others develop within the ovary and are nourished by ovarian tissues after hatching (viviparous). There are also other methods utilized by fishes to nourish young within the female. In all live-bearers the young are born at a relatively large size and are few in number. In one family of primarily marine fishes, the surfperches from the Pacific coast of North America, Japan, and Korea, the males of at least one species are born sexually mature, although they are not fully grown.

 

Some fishes are hermaphroditic—an individual producing both sperm and eggs, usually at different stages of its life. Self-fertilization, however, is probably rare.

 

Successful reproduction and, in many cases, defense of the eggs and the young are assured by rather stereotypical but often elaborate courtship and parental behaviour, either by the male or the female or both. Some fishes prepare nests by hollowing out depressions in the sand bottom (cichlids, for example), build nests with plant materials and sticky threads excreted by the kidneys (sticklebacks), or blow a cluster of mucus-covered bubbles at the water surface (gouramis). The eggs are laid in these structures. Some varieties of cichlids and catfishes incubate eggs in their mouths.

 

Some fishes, such as salmon, undergo long migrations from the ocean and up large rivers to spawn in the gravel beds where they themselves hatched (anadromous fishes). Some, such as the freshwater eels (family Anguillidae), live and grow to maturity in fresh water and migrate to the sea to spawn (catadromous fishes). Other fishes undertake shorter migrations from lakes into streams, within the ocean, or enter spawning habitats that they do not ordinarily occupy in other ways.

 

The basic structure and function of the fish body are similar to those of all other vertebrates. The usual four types of tissues are present: surface or epithelial, connective (bone, cartilage, and fibrous tissues, as well as their derivative, blood), nerve, and muscle tissues. In addition, the fish’s organs and organ systems parallel those of other vertebrates.

 

The typical fish body is streamlined and spindle-shaped, with an anterior head, a gill apparatus, and a heart, the latter lying in the midline just below the gill chamber. The body cavity, containing the vital organs, is situated behind the head in the lower anterior part of the body. The anus usually marks the posterior termination of the body cavity and most often occurs just in front of the base of the anal fin. The spinal cord and vertebral column continue from the posterior part of the head to the base of the tail fin, passing dorsal to the body cavity and through the caudal (tail) region behind the body cavity. Most of the body is of muscular tissue, a high proportion of which is necessitated by swimming. In the course of evolution this basic body plan has been modified repeatedly into the many varieties of fish shapes that exist today.

 

The skeleton forms an integral part of the fish’s locomotion system, as well as serving to protect vital parts. The internal skeleton consists of the skull bones (except for the roofing bones of the head, which are really part of the external skeleton), the vertebral column, and the fin supports (fin rays). The fin supports are derived from the external skeleton but will be treated here because of their close functional relationship to the internal skeleton. The internal skeleton of cyclostomes, sharks, and rays is of cartilage; that of many fossil groups and some primitive living fishes is mostly of cartilage but may include some bone. In place of the vertebral column, the earliest vertebrates had a fully developed notochord, a flexible stiff rod of viscous cells surrounded by a strong fibrous sheath. During the evolution of modern fishes the rod was replaced in part by cartilage and then by ossified cartilage. Sharks and rays retain a cartilaginous vertebral column; bony fishes have spool-shaped vertebrae that in the more primitive living forms only partially replace the notochord. The skull, including the gill arches and jaws of bony fishes, is fully, or at least partially, ossified. That of sharks and rays remains cartilaginous, at times partially replaced by calcium deposits but never by true bone.

 

The supportive elements of the fins (basal or radial bones or both) have changed greatly during fish evolution. Some of these changes are described in the section below (Evolution and paleontology). Most fishes possess a single dorsal fin on the midline of the back. Many have two and a few have three dorsal fins. The other fins are the single tail and anal fins and paired pelvic and pectoral fins. A small fin, the adipose fin, with hairlike fin rays, occurs in many of the relatively primitive teleosts (such as trout) on the back near the base of the caudal fin.

 

The skin of a fish must serve many functions. It aids in maintaining the osmotic balance, provides physical protection for the body, is the site of coloration, contains sensory receptors, and, in some fishes, functions in respiration. Mucous glands, which aid in maintaining the water balance and offer protection from bacteria, are extremely numerous in fish skin, especially in cyclostomes and teleosts. Since mucous glands are present in the modern lampreys, it is reasonable to assume that they were present in primitive fishes, such as the ancient Silurian and Devonian agnathans. Protection from abrasion and predation is another function of the fish skin, and dermal (skin) bone arose early in fish evolution in response to this need. It is thought that bone first evolved in skin and only later invaded the cartilaginous areas of the fish’s body, to provide additional support and protection. There is some argument as to which came first, cartilage or bone, and fossil evidence does not settle the question. In any event, dermal bone has played an important part in fish evolution and has different characteristics in different groups of fishes. Several groups are characterized at least in part by the kind of bony scales they possess.

 

Scales have played an important part in the evolution of fishes. Primitive fishes usually had thick bony plates or thick scales in several layers of bone, enamel, and related substances. Modern teleost fishes have scales of bone, which, while still protective, allow much more freedom of motion in the body. A few modern teleosts (some catfishes, sticklebacks, and others) have secondarily acquired bony plates in the skin. Modern and early sharks possessed placoid scales, a relatively primitive type of scale with a toothlike structure, consisting of an outside layer of enamel-like substance (vitrodentine), an inner layer of dentine, and a pulp cavity containing nerves and blood vessels. Primitive bony fishes had thick scales of either the ganoid or the cosmoid type. Cosmoid scales have a hard, enamel-like outer layer, an inner layer of cosmine (a form of dentine), and then a layer of vascular bone (isopedine). In ganoid scales the hard outer layer is different chemically and is called ganoin. Under this is a cosminelike layer and then a vascular bony layer. The thin, translucent bony scales of modern fishes, called cycloid and ctenoid (the latter distinguished by serrations at the edges), lack enameloid and dentine layers.

 

Skin has several other functions in fishes. It is well supplied with nerve endings and presumably receives tactile, thermal, and pain stimuli. Skin is also well supplied with blood vessels. Some fishes breathe in part through the skin, by the exchange of oxygen and carbon dioxide between the surrounding water and numerous small blood vessels near the skin surface.

 

Skin serves as protection through the control of coloration. Fishes exhibit an almost limitless range of colours. The colours often blend closely with the surroundings, effectively hiding the animal. Many fishes use bright colours for territorial advertisement or as recognition marks for other members of their own species, or sometimes for members of other species. Many fishes can change their colour to a greater or lesser degree, by movement of pigment within the pigment cells (chromatophores). Black pigment cells (melanophores), of almost universal occurrence in fishes, are often juxtaposed with other pigment cells. When placed beneath iridocytes or leucophores (bearing the silvery or white pigment guanine), melanophores produce structural colours of blue and green. These colours are often extremely intense, because they are formed by refraction of light through the needlelike crystals of guanine. The blue and green refracted colours are often relatively pure, lacking the red and yellow rays, which have been absorbed by the black pigment (melanin) of the melanophores. Yellow, orange, and red colours are produced by erythrophores, cells containing the appropriate carotenoid pigments. Other colours are produced by combinations of melanophores, erythrophores, and iridocytes.

 

The major portion of the body of most fishes consists of muscles. Most of the mass is trunk musculature, the fin muscles usually being relatively small. The caudal fin is usually the most powerful fin, being moved by the trunk musculature. The body musculature is usually arranged in rows of chevron-shaped segments on each side. Contractions of these segments, each attached to adjacent vertebrae and vertebral processes, bends the body on the vertebral joint, producing successive undulations of the body, passing from the head to the tail, and producing driving strokes of the tail. It is the latter that provides the strong forward movement for most fishes.

 

The digestive system, in a functional sense, starts at the mouth, with the teeth used to capture prey or collect plant foods. Mouth shape and tooth structure vary greatly in fishes, depending on the kind of food normally eaten. Most fishes are predacious, feeding on small invertebrates or other fishes and have simple conical teeth on the jaws, on at least some of the bones of the roof of the mouth, and on special gill arch structures just in front of the esophagus. The latter are throat teeth. Most predacious fishes swallow their prey whole, and the teeth are used for grasping and holding prey, for orienting prey to be swallowed (head first) and for working the prey toward the esophagus. There are a variety of tooth types in fishes. Some fishes, such as sharks and piranhas, have cutting teeth for biting chunks out of their victims. A shark’s tooth, although superficially like that of a piranha, appears in many respects to be a modified scale, while that of the piranha is like that of other bony fishes, consisting of dentine and enamel. Parrot fishes have beaklike mouths with short incisor-like teeth for breaking off coral and have heavy pavementlike throat teeth for crushing the coral. Some catfishes have small brushlike teeth, arranged in rows on the jaws, for scraping plant and animal growth from rocks. Many fishes (such as the Cyprinidae or minnows) have no jaw teeth at all but have very strong throat teeth.

 

Some fishes gather planktonic food by straining it from their gill cavities with numerous elongate stiff rods (gill rakers) anchored by one end to the gill bars. The food collected on these rods is passed to the throat, where it is swallowed. Most fishes have only short gill rakers that help keep food particles from escaping out the mouth cavity into the gill chamber.

 

Once reaching the throat, food enters a short, often greatly distensible esophagus, a simple tube with a muscular wall leading into a stomach. The stomach varies greatly in fishes, depending upon the diet. In most predacious fishes it is a simple straight or curved tube or pouch with a muscular wall and a glandular lining. Food is largely digested there and leaves the stomach in liquid form.

 

Between the stomach and the intestine, ducts enter the digestive tube from the liver and pancreas. The liver is a large, clearly defined organ. The pancreas may be embedded in it, diffused through it, or broken into small parts spread along some of the intestine. The junction between the stomach and the intestine is marked by a muscular valve. Pyloric ceca (blind sacs) occur in some fishes at this junction and have a digestive or absorptive function or both.

 

The intestine itself is quite variable in length, depending upon the fish’s diet. It is short in predacious forms, sometimes no longer than the body cavity, but long in herbivorous forms, being coiled and several times longer than the entire length of the fish in some species of South American catfishes. The intestine is primarily an organ for absorbing nutrients into the bloodstream. The larger its internal surface, the greater its absorptive efficiency, and a spiral valve is one method of increasing its absorption surface.

 

Sharks, rays, chimaeras, lungfishes, surviving chondrosteans, holosteans, and even a few of the more primitive teleosts have a spiral valve or at least traces of it in the intestine. Most modern teleosts have increased the area of the intestinal walls by having numerous folds and villi (fingerlike projections) somewhat like those in humans. Undigested substances are passed to the exterior through the anus in most teleost fishes. In lungfishes, sharks, and rays, it is first passed through the cloaca, a common cavity receiving the intestinal opening and the ducts from the urogenital system.

 

Oxygen and carbon dioxide dissolve in water, and most fishes exchange dissolved oxygen and carbon dioxide in water by means of the gills. The gills lie behind and to the side of the mouth cavity and consist of fleshy filaments supported by the gill arches and filled with blood vessels, which give gills a bright red colour. Water taken in continuously through the mouth passes backward between the gill bars and over the gill filaments, where the exchange of gases takes place. The gills are protected by a gill cover in teleosts and many other fishes but by flaps of skin in sharks, rays, and some of the older fossil fish groups. The blood capillaries in the gill filaments are close to the gill surface to take up oxygen from the water and to give up excess carbon dioxide to the water.

 

Most modern fishes have a hydrostatic (ballast) organ, called the swim bladder, that lies in the body cavity just below the kidney and above the stomach and intestine. It originated as a diverticulum of the digestive canal. In advanced teleosts, especially the acanthopterygians, the bladder has lost its connection with the digestive tract, a condition called physoclistic. The connection has been retained (physostomous) by many relatively primitive teleosts. In several unrelated lines of fishes, the bladder has become specialized as a lung or, at least, as a highly vascularized accessory breathing organ. Some fishes with such accessory organs are obligate air breathers and will drown if denied access to the surface, even in well-oxygenated water. Fishes with a hydrostatic form of swim bladder can control their depth by regulating the amount of gas in the bladder. The gas, mostly oxygen, is secreted into the bladder by special glands, rendering the fish more buoyant; the gas is absorbed into the bloodstream by another special organ, reducing the overall buoyancy and allowing the fish to sink. Some deep-sea fishes may have oils, rather than gas, in the bladder. Other deep-sea and some bottom-living forms have much-reduced swim bladders or have lost the organ entirely.

 

The swim bladder of fishes follows the same developmental pattern as the lungs of land vertebrates. There is no doubt that the two structures have the same historical origin in primitive fishes. More or less intermediate forms still survive among the more primitive types of fishes, such as the lungfishes Lepidosiren and Protopterus.

 

The circulatory, or blood vascular, system consists of the heart, the arteries, the capillaries, and the veins. It is in the capillaries that the interchange of oxygen, carbon dioxide, nutrients, and other substances such as hormones and waste products takes place. The capillaries lead to the veins, which return the venous blood with its waste products to the heart, kidneys, and gills. There are two kinds of capillary beds: those in the gills and those in the rest of the body. The heart, a folded continuous muscular tube with three or four saclike enlargements, undergoes rhythmic contractions and receives venous blood in a sinus venosus. It passes the blood to an auricle and then into a thick muscular pump, the ventricle. From the ventricle the blood goes to a bulbous structure at the base of a ventral aorta just below the gills. The blood passes to the afferent (receiving) arteries of the gill arches and then to the gill capillaries. There waste gases are given off to the environment, and oxygen is absorbed. The oxygenated blood enters efferent (exuant) arteries of the gill arches and then flows into the dorsal aorta. From there blood is distributed to the tissues and organs of the body. One-way valves prevent backflow. The circulation of fishes thus differs from that of the reptiles, birds, and mammals in that oxygenated blood is not returned to the heart prior to distribution to the other parts of the body.

 

The primary excretory organ in fishes, as in other vertebrates, is the kidney. In fishes some excretion also takes place in the digestive tract, skin, and especially the gills (where ammonia is given off). Compared with land vertebrates, fishes have a special problem in maintaining their internal environment at a constant concentration of water and dissolved substances, such as salts. Proper balance of the internal environment (homeostasis) of a fish is in a great part maintained by the excretory system, especially the kidney.

 

The kidney, gills, and skin play an important role in maintaining a fish’s internal environment and checking the effects of osmosis. Marine fishes live in an environment in which the water around them has a greater concentration of salts than they can have inside their body and still maintain life. Freshwater fishes, on the other hand, live in water with a much lower concentration of salts than they require inside their bodies. Osmosis tends to promote the loss of water from the body of a marine fish and absorption of water by that of a freshwater fish. Mucus in the skin tends to slow the process but is not a sufficient barrier to prevent the movement of fluids through the permeable skin. When solutions on two sides of a permeable membrane have different concentrations of dissolved substances, water will pass through the membrane into the more concentrated solution, while the dissolved chemicals move into the area of lower concentration (diffusion).

 

The kidney of freshwater fishes is often larger in relation to body weight than that of marine fishes. In both groups the kidney excretes wastes from the body, but the kidney of freshwater fishes also excretes large amounts of water, counteracting the water absorbed through the skin. Freshwater fishes tend to lose salt to the environment and must replace it. They get some salt from their food, but the gills and skin inside the mouth actively absorb salt from water passed through the mouth. This absorption is performed by special cells capable of moving salts against the diffusion gradient. Freshwater fishes drink very little water and take in little water with their food.

 

Marine fishes must conserve water, and therefore their kidneys excrete little water. To maintain their water balance, marine fishes drink large quantities of seawater, retaining most of the water and excreting the salt. Most nitrogenous waste in marine fishes appears to be secreted by the gills as ammonia. Marine fishes can excrete salt by clusters of special cells (chloride cells) in the gills.

 

There are several teleosts—for example, the salmon—that travel between fresh water and seawater and must adjust to the reversal of osmotic gradients. They adjust their physiological processes by spending time (often surprisingly little time) in the intermediate brackish environment.

 

Marine hagfishes, sharks, and rays have osmotic concentrations in their blood about equal to that of seawater and so do not have to drink water nor perform much physiological work to maintain their osmotic balance. In sharks and rays the osmotic concentration is kept high by retention of urea in the blood. Freshwater sharks have a lowered concentration of urea in the blood.

 

Endocrine glands secrete their products into the bloodstream and body tissues and, along with the central nervous system, control and regulate many kinds of body functions. Cyclostomes have a well-developed endocrine system, and presumably it was well developed in the early Agnatha, ancestral to modern fishes. Although the endocrine system in fishes is similar to that of higher vertebrates, there are numerous differences in detail. The pituitary, the thyroid, the suprarenals, the adrenals, the pancreatic islets, the sex glands (ovaries and testes), the inner wall of the intestine, and the bodies of the ultimobranchial gland make up the endocrine system in fishes. There are some others whose function is not well understood. These organs regulate sexual activity and reproduction, growth, osmotic pressure, general metabolic activities such as the storage of fat and the utilization of foodstuffs, blood pressure, and certain aspects of skin colour. Many of these activities are also controlled in part by the central nervous system, which works with the endocrine system in maintaining the life of a fish. Some parts of the endocrine system are developmentally, and undoubtedly evolutionarily, derived from the nervous system.

 

As in all vertebrates, the nervous system of fishes is the primary mechanism coordinating body activities, as well as integrating these activities in the appropriate manner with stimuli from the environment. The central nervous system, consisting of the brain and spinal cord, is the primary integrating mechanism. The peripheral nervous system, consisting of nerves that connect the brain and spinal cord to various body organs, carries sensory information from special receptor organs such as the eyes, internal ears, nares (sense of smell), taste glands, and others to the integrating centres of the brain and spinal cord. The peripheral nervous system also carries information via different nerve cells from the integrating centres of the brain and spinal cord. This coded information is carried to the various organs and body systems, such as the skeletal muscular system, for appropriate action in response to the original external or internal stimulus. Another branch of the nervous system, the autonomic nervous system, helps to coordinate the activities of many glands and organs and is itself closely connected to the integrating centres of the brain.

 

The brain of the fish is divided into several anatomical and functional parts, all closely interconnected but each serving as the primary centre of integrating particular kinds of responses and activities. Several of these centres or parts are primarily associated with one type of sensory perception, such as sight, hearing, or smell (olfaction).

 

The sense of smell is important in almost all fishes. Certain eels with tiny eyes depend mostly on smell for location of food. The olfactory, or nasal, organ of fishes is located on the dorsal surface of the snout. The lining of the nasal organ has special sensory cells that perceive chemicals dissolved in the water, such as substances from food material, and send sensory information to the brain by way of the first cranial nerve. Odour also serves as an alarm system. Many fishes, especially various species of freshwater minnows, react with alarm to a chemical released from the skin of an injured member of their own species.

 

Many fishes have a well-developed sense of taste, and tiny pitlike taste buds or organs are located not only within their mouth cavities but also over their heads and parts of their body. Catfishes, which often have poor vision, have barbels (“whiskers”) that serve as supplementary taste organs, those around the mouth being actively used to search out food on the bottom. Some species of naturally blind cave fishes are especially well supplied with taste buds, which often cover most of their body surface.

 

Sight is extremely important in most fishes. The eye of a fish is basically like that of all other vertebrates, but the eyes of fishes are extremely varied in structure and adaptation. In general, fishes living in dark and dim water habitats have large eyes, unless they have specialized in some compensatory way so that another sense (such as smell) is dominant, in which case the eyes will often be reduced. Fishes living in brightly lighted shallow waters often will have relatively small but efficient eyes. Cyclostomes have somewhat less elaborate eyes than other fishes, with skin stretched over the eyeball perhaps making their vision somewhat less effective. Most fishes have a spherical lens and accommodate their vision to far or near subjects by moving the lens within the eyeball. A few sharks accommodate by changing the shape of the lens, as in land vertebrates. Those fishes that are heavily dependent upon the eyes have especially strong muscles for accommodation. Most fishes see well, despite the restrictions imposed by frequent turbidity of the water and by light refraction.

 

Fossil evidence suggests that colour vision evolved in fishes more than 300 million years ago, but not all living fishes have retained this ability. Experimental evidence indicates that many shallow-water fishes, if not all, have colour vision and see some colours especially well, but some bottom-dwelling shore fishes live in areas where the water is sufficiently deep to filter out most if not all colours, and these fishes apparently never see colours. When tested in shallow water, they apparently are unable to respond to colour differences.

 

Sound perception and balance are intimately associated senses in a fish. The organs of hearing are entirely internal, located within the skull, on each side of the brain and somewhat behind the eyes. Sound waves, especially those of low frequencies, travel readily through water and impinge directly upon the bones and fluids of the head and body, to be transmitted to the hearing organs. Fishes readily respond to sound; for example, a trout conditioned to escape by the approach of fishermen will take flight upon perceiving footsteps on a stream bank even if it cannot see a fisherman. Compared with humans, however, the range of sound frequencies heard by fishes is greatly restricted. Many fishes communicate with each other by producing sounds in their swim bladders, in their throats by rasping their teeth, and in other ways.

 

A fish or other vertebrate seldom has to rely on a single type of sensory information to determine the nature of the environment around it. A catfish uses taste and touch when examining a food object with its oral barbels. Like most other animals, fishes have many touch receptors over their body surface. Pain and temperature receptors also are present in fishes and presumably produce the same kind of information to a fish as to humans. Fishes react in a negative fashion to stimuli that would be painful to human beings, suggesting that they feel a sensation of pain.

 

An important sensory system in fishes that is absent in other vertebrates (except some amphibians) is the lateral line system. This consists of a series of heavily innervated small canals located in the skin and bone around the eyes, along the lower jaw, over the head, and down the mid-side of the body, where it is associated with the scales. Intermittently along these canals are located tiny sensory organs (pit organs) that apparently detect changes in pressure. The system allows a fish to sense changes in water currents and pressure, thereby helping the fish to orient itself to the various changes that occur in the physical environment.

  

Fish, any of approximately 34,000 species of vertebrate animals (phylum Chordata) found in the fresh and salt waters of the world. Living species range from the primitive jawless lampreys and hagfishes through the cartilaginous sharks, skates, and rays to the abundant and diverse bony fishes. Most fish species are cold-blooded; however, one species, the opah (Lampris guttatus), is warm-blooded.

 

The term fish is applied to a variety of vertebrates of several evolutionary lines. It describes a life-form rather than a taxonomic group. As members of the phylum Chordata, fish share certain features with other vertebrates. These features are gill slits at some point in the life cycle, a notochord, or skeletal supporting rod, a dorsal hollow nerve cord, and a tail. Living fishes represent some five classes, which are as distinct from one another as are the four classes of familiar air-breathing animals—amphibians, reptiles, birds, and mammals. For example, the jawless fishes (Agnatha) have gills in pouches and lack limb girdles. Extant agnathans are the lampreys and the hagfishes. As the name implies, the skeletons of fishes of the class Chondrichthyes (from chondr, “cartilage,” and ichthyes, “fish”) are made entirely of cartilage. Modern fish of this class lack a swim bladder, and their scales and teeth are made up of the same placoid material. Sharks, skates, and rays are examples of cartilaginous fishes. The bony fishes are by far the largest class. Examples range from the tiny seahorse to the 450-kg (1,000-pound) blue marlin, from the flattened soles and flounders to the boxy puffers and ocean sunfishes. Unlike the scales of the cartilaginous fishes, those of bony fishes, when present, grow throughout life and are made up of thin overlapping plates of bone. Bony fishes also have an operculum that covers the gill slits.

 

The study of fishes, the science of ichthyology, is of broad importance. Fishes are of interest to humans for many reasons, the most important being their relationship with and dependence on the environment. A more obvious reason for interest in fishes is their role as a moderate but important part of the world’s food supply. This resource, once thought unlimited, is now realized to be finite and in delicate balance with the biological, chemical, and physical factors of the aquatic environment. Overfishing, pollution, and alteration of the environment are the chief enemies of proper fisheries management, both in fresh waters and in the ocean. (For a detailed discussion of the technology and economics of fisheries, see commercial fishing.) Another practical reason for studying fishes is their use in disease control. As predators on mosquito larvae, they help curb malaria and other mosquito-borne diseases.

 

Fishes are valuable laboratory animals in many aspects of medical and biological research. For example, the readiness of many fishes to acclimate to captivity has allowed biologists to study behaviour, physiology, and even ecology under relatively natural conditions. Fishes have been especially important in the study of animal behaviour, where research on fishes has provided a broad base for the understanding of the more flexible behaviour of the higher vertebrates. The zebra fish is used as a model in studies of gene expression.

 

There are aesthetic and recreational reasons for an interest in fishes. Millions of people keep live fishes in home aquariums for the simple pleasure of observing the beauty and behaviour of animals otherwise unfamiliar to them. Aquarium fishes provide a personal challenge to many aquarists, allowing them to test their ability to keep a small section of the natural environment in their homes. Sportfishing is another way of enjoying the natural environment, also indulged in by millions of people every year. Interest in aquarium fishes and sportfishing supports multimillion-dollar industries throughout the world.

 

Fishes have been in existence for more than 450 million years, during which time they have evolved repeatedly to fit into almost every conceivable type of aquatic habitat. In a sense, land vertebrates are simply highly modified fishes: when fishes colonized the land habitat, they became tetrapod (four-legged) land vertebrates. The popular conception of a fish as a slippery, streamlined aquatic animal that possesses fins and breathes by gills applies to many fishes, but far more fishes deviate from that conception than conform to it. For example, the body is elongate in many forms and greatly shortened in others; the body is flattened in some (principally in bottom-dwelling fishes) and laterally compressed in many others; the fins may be elaborately extended, forming intricate shapes, or they may be reduced or even lost; and the positions of the mouth, eyes, nostrils, and gill openings vary widely. Air breathers have appeared in several evolutionary lines.

 

Many fishes are cryptically coloured and shaped, closely matching their respective environments; others are among the most brilliantly coloured of all organisms, with a wide range of hues, often of striking intensity, on a single individual. The brilliance of pigments may be enhanced by the surface structure of the fish, so that it almost seems to glow. A number of unrelated fishes have actual light-producing organs. Many fishes are able to alter their coloration—some for the purpose of camouflage, others for the enhancement of behavioral signals.

 

Fishes range in adult length from less than 10 mm (0.4 inch) to more than 20 metres (60 feet) and in weight from about 1.5 grams (less than 0.06 ounce) to many thousands of kilograms. Some live in shallow thermal springs at temperatures slightly above 42 °C (100 °F), others in cold Arctic seas a few degrees below 0 °C (32 °F) or in cold deep waters more than 4,000 metres (13,100 feet) beneath the ocean surface. The structural and, especially, the physiological adaptations for life at such extremes are relatively poorly known and provide the scientifically curious with great incentive for study.

 

Almost all natural bodies of water bear fish life, the exceptions being very hot thermal ponds and extremely salt-alkaline lakes, such as the Dead Sea in Asia and the Great Salt Lake in North America. The present distribution of fishes is a result of the geological history and development of Earth as well as the ability of fishes to undergo evolutionary change and to adapt to the available habitats. Fishes may be seen to be distributed according to habitat and according to geographical area. Major habitat differences are marine and freshwater. For the most part, the fishes in a marine habitat differ from those in a freshwater habitat, even in adjacent areas, but some, such as the salmon, migrate from one to the other. The freshwater habitats may be seen to be of many kinds. Fishes found in mountain torrents, Arctic lakes, tropical lakes, temperate streams, and tropical rivers will all differ from each other, both in obvious gross structure and in physiological attributes. Even in closely adjacent habitats where, for example, a tropical mountain torrent enters a lowland stream, the fish fauna will differ. The marine habitats can be divided into deep ocean floors (benthic), mid-water oceanic (bathypelagic), surface oceanic (pelagic), rocky coast, sandy coast, muddy shores, bays, estuaries, and others. Also, for example, rocky coastal shores in tropical and temperate regions will have different fish faunas, even when such habitats occur along the same coastline.

 

Although much is known about the present geographical distribution of fishes, far less is known about how that distribution came about. Many parts of the fish fauna of the fresh waters of North America and Eurasia are related and undoubtedly have a common origin. The faunas of Africa and South America are related, extremely old, and probably an expression of the drifting apart of the two continents. The fauna of southern Asia is related to that of Central Asia, and some of it appears to have entered Africa. The extremely large shore-fish faunas of the Indian and tropical Pacific oceans comprise a related complex, but the tropical shore fauna of the Atlantic, although containing Indo-Pacific components, is relatively limited and probably younger. The Arctic and Antarctic marine faunas are quite different from each other. The shore fauna of the North Pacific is quite distinct, and that of the North Atlantic more limited and probably younger. Pelagic oceanic fishes, especially those in deep waters, are similar the world over, showing little geographical isolation in terms of family groups. The deep oceanic habitat is very much the same throughout the world, but species differences do exist, showing geographical areas determined by oceanic currents and water masses.

 

All aspects of the life of a fish are closely correlated with adaptation to the total environment, physical, chemical, and biological. In studies, all the interdependent aspects of fish, such as behaviour, locomotion, reproduction, and physical and physiological characteristics, must be taken into account.

 

Correlated with their adaptation to an extremely wide variety of habitats is the extremely wide variety of life cycles that fishes display. The great majority hatch from relatively small eggs a few days to several weeks or more after the eggs are scattered in the water. Newly hatched young are still partially undeveloped and are called larvae until body structures such as fins, skeleton, and some organs are fully formed. Larval life is often very short, usually less than a few weeks, but it can be very long, some lampreys continuing as larvae for at least five years. Young and larval fishes, before reaching sexual maturity, must grow considerably, and their small size and other factors often dictate that they live in a habitat different than that of the adults. For example, most tropical marine shore fishes have pelagic larvae. Larval food also is different, and larval fishes often live in shallow waters, where they may be less exposed to predators.

 

After a fish reaches adult size, the length of its life is subject to many factors, such as innate rates of aging, predation pressure, and the nature of the local climate. The longevity of a species in the protected environment of an aquarium may have nothing to do with how long members of that species live in the wild. Many small fishes live only one to three years at the most. In some species, however, individuals may live as long as 10 or 20 or even 100 years.

 

Fish behaviour is a complicated and varied subject. As in almost all animals with a central nervous system, the nature of a response of an individual fish to stimuli from its environment depends upon the inherited characteristics of its nervous system, on what it has learned from past experience, and on the nature of the stimuli. Compared with the variety of human responses, however, that of a fish is stereotyped, not subject to much modification by “thought” or learning, and investigators must guard against anthropomorphic interpretations of fish behaviour.

 

Fishes perceive the world around them by the usual senses of sight, smell, hearing, touch, and taste and by special lateral line water-current detectors. In the few fishes that generate electric fields, a process that might best be called electrolocation aids in perception. One or another of these senses often is emphasized at the expense of others, depending upon the fish’s other adaptations. In fishes with large eyes, the sense of smell may be reduced; others, with small eyes, hunt and feed primarily by smell (such as some eels).

 

Specialized behaviour is primarily concerned with the three most important activities in the fish’s life: feeding, reproduction, and escape from enemies. Schooling behaviour of sardines on the high seas, for instance, is largely a protective device to avoid enemies, but it is also associated with and modified by their breeding and feeding requirements. Predatory fishes are often solitary, lying in wait to dart suddenly after their prey, a kind of locomotion impossible for beaked parrot fishes, which feed on coral, swimming in small groups from one coral head to the next. In addition, some predatory fishes that inhabit pelagic environments, such as tunas, often school.

 

Sleep in fishes, all of which lack true eyelids, consists of a seemingly listless state in which the fish maintains its balance but moves slowly. If attacked or disturbed, most can dart away. A few kinds of fishes lie on the bottom to sleep. Most catfishes, some loaches, and some eels and electric fishes are strictly nocturnal, being active and hunting for food during the night and retiring during the day to holes, thick vegetation, or other protective parts of the environment.

 

Communication between members of a species or between members of two or more species often is extremely important, especially in breeding behaviour (see below Reproduction). The mode of communication may be visual, as between the small so-called cleaner fish and a large fish of a very different species. The larger fish often allows the cleaner to enter its mouth to remove gill parasites. The cleaner is recognized by its distinctive colour and actions and therefore is not eaten, even if the larger fish is normally a predator. Communication is often chemical, signals being sent by specific chemicals called pheromones.

 

Many fishes have a streamlined body and swim freely in open water. Fish locomotion is closely correlated with habitat and ecological niche (the general position of the animal to its environment).

 

Many fishes in both marine and fresh waters swim at the surface and have mouths adapted to feed best (and sometimes only) at the surface. Often such fishes are long and slender, able to dart at surface insects or at other surface fishes and in turn to dart away from predators; needlefishes, halfbeaks, and topminnows (such as killifish and mosquito fish) are good examples. Oceanic flying fishes escape their predators by gathering speed above the water surface, with the lower lobe of the tail providing thrust in the water. They then glide hundreds of yards on enlarged, winglike pectoral and pelvic fins. South American freshwater flying fishes escape their enemies by jumping and propelling their strongly keeled bodies out of the water.

 

So-called mid-water swimmers, the most common type of fish, are of many kinds and live in many habitats. The powerful fusiform tunas and the trouts, for example, are adapted for strong, fast swimming, the tunas to capture prey speedily in the open ocean and the trouts to cope with the swift currents of streams and rivers. The trout body form is well adapted to many habitats. Fishes that live in relatively quiet waters such as bays or lake shores or slow rivers usually are not strong, fast swimmers but are capable of short, quick bursts of speed to escape a predator. Many of these fishes have their sides flattened, examples being the sunfish and the freshwater angelfish of aquarists. Fish associated with the bottom or substrate usually are slow swimmers. Open-water plankton-feeding fishes almost always remain fusiform and are capable of rapid, strong movement (for example, sardines and herrings of the open ocean and also many small minnows of streams and lakes).

 

Bottom-living fishes are of many kinds and have undergone many types of modification of their body shape and swimming habits. Rays, which evolved from strong-swimming mid-water sharks, usually stay close to the bottom and move by undulating their large pectoral fins. Flounders live in a similar habitat and move over the bottom by undulating the entire body. Many bottom fishes dart from place to place, resting on the bottom between movements, a motion common in gobies. One goby relative, the mudskipper, has taken to living at the edge of pools along the shore of muddy mangrove swamps. It escapes its enemies by flipping rapidly over the mud, out of the water. Some catfishes, synbranchid eels, the so-called climbing perch, and a few other fishes venture out over damp ground to find more promising waters than those that they left. They move by wriggling their bodies, sometimes using strong pectoral fins; most have accessory air-breathing organs. Many bottom-dwelling fishes live in mud holes or rocky crevices. Marine eels and gobies commonly are found in such habitats and for the most part venture far beyond their cavelike homes. Some bottom dwellers, such as the clingfishes (Gobiesocidae), have developed powerful adhesive disks that enable them to remain in place on the substrate in areas such as rocky coasts, where the action of the waves is great.

 

The methods of reproduction in fishes are varied, but most fishes lay a large number of small eggs, fertilized and scattered outside of the body. The eggs of pelagic fishes usually remain suspended in the open water. Many shore and freshwater fishes lay eggs on the bottom or among plants. Some have adhesive eggs. The mortality of the young and especially of the eggs is very high, and often only a few individuals grow to maturity out of hundreds, thousands, and in some cases millions of eggs laid.

 

Males produce sperm, usually as a milky white substance called milt, in two (sometimes one) testes within the body cavity. In bony fishes a sperm duct leads from each testis to a urogenital opening behind the vent or anus. In sharks and rays and in cyclostomes the duct leads to a cloaca. Sometimes the pelvic fins are modified to help transmit the milt to the eggs at the female’s vent or on the substrate where the female has placed them. Sometimes accessory organs are used to fertilize females internally—for example, the claspers of many sharks and rays.

 

In the females the eggs are formed in two ovaries (sometimes only one) and pass through the ovaries to the urogenital opening and to the outside. In some fishes the eggs are fertilized internally but are shed before development takes place. Members of about a dozen families each of bony fishes (teleosts) and sharks bear live young. Many skates and rays also bear live young. In some bony fishes the eggs simply develop within the female, the young emerging when the eggs hatch (ovoviviparous). Others develop within the ovary and are nourished by ovarian tissues after hatching (viviparous). There are also other methods utilized by fishes to nourish young within the female. In all live-bearers the young are born at a relatively large size and are few in number. In one family of primarily marine fishes, the surfperches from the Pacific coast of North America, Japan, and Korea, the males of at least one species are born sexually mature, although they are not fully grown.

 

Some fishes are hermaphroditic—an individual producing both sperm and eggs, usually at different stages of its life. Self-fertilization, however, is probably rare.

 

Successful reproduction and, in many cases, defense of the eggs and the young are assured by rather stereotypical but often elaborate courtship and parental behaviour, either by the male or the female or both. Some fishes prepare nests by hollowing out depressions in the sand bottom (cichlids, for example), build nests with plant materials and sticky threads excreted by the kidneys (sticklebacks), or blow a cluster of mucus-covered bubbles at the water surface (gouramis). The eggs are laid in these structures. Some varieties of cichlids and catfishes incubate eggs in their mouths.

 

Some fishes, such as salmon, undergo long migrations from the ocean and up large rivers to spawn in the gravel beds where they themselves hatched (anadromous fishes). Some, such as the freshwater eels (family Anguillidae), live and grow to maturity in fresh water and migrate to the sea to spawn (catadromous fishes). Other fishes undertake shorter migrations from lakes into streams, within the ocean, or enter spawning habitats that they do not ordinarily occupy in other ways.

 

The basic structure and function of the fish body are similar to those of all other vertebrates. The usual four types of tissues are present: surface or epithelial, connective (bone, cartilage, and fibrous tissues, as well as their derivative, blood), nerve, and muscle tissues. In addition, the fish’s organs and organ systems parallel those of other vertebrates.

 

The typical fish body is streamlined and spindle-shaped, with an anterior head, a gill apparatus, and a heart, the latter lying in the midline just below the gill chamber. The body cavity, containing the vital organs, is situated behind the head in the lower anterior part of the body. The anus usually marks the posterior termination of the body cavity and most often occurs just in front of the base of the anal fin. The spinal cord and vertebral column continue from the posterior part of the head to the base of the tail fin, passing dorsal to the body cavity and through the caudal (tail) region behind the body cavity. Most of the body is of muscular tissue, a high proportion of which is necessitated by swimming. In the course of evolution this basic body plan has been modified repeatedly into the many varieties of fish shapes that exist today.

 

The skeleton forms an integral part of the fish’s locomotion system, as well as serving to protect vital parts. The internal skeleton consists of the skull bones (except for the roofing bones of the head, which are really part of the external skeleton), the vertebral column, and the fin supports (fin rays). The fin supports are derived from the external skeleton but will be treated here because of their close functional relationship to the internal skeleton. The internal skeleton of cyclostomes, sharks, and rays is of cartilage; that of many fossil groups and some primitive living fishes is mostly of cartilage but may include some bone. In place of the vertebral column, the earliest vertebrates had a fully developed notochord, a flexible stiff rod of viscous cells surrounded by a strong fibrous sheath. During the evolution of modern fishes the rod was replaced in part by cartilage and then by ossified cartilage. Sharks and rays retain a cartilaginous vertebral column; bony fishes have spool-shaped vertebrae that in the more primitive living forms only partially replace the notochord. The skull, including the gill arches and jaws of bony fishes, is fully, or at least partially, ossified. That of sharks and rays remains cartilaginous, at times partially replaced by calcium deposits but never by true bone.

 

The supportive elements of the fins (basal or radial bones or both) have changed greatly during fish evolution. Some of these changes are described in the section below (Evolution and paleontology). Most fishes possess a single dorsal fin on the midline of the back. Many have two and a few have three dorsal fins. The other fins are the single tail and anal fins and paired pelvic and pectoral fins. A small fin, the adipose fin, with hairlike fin rays, occurs in many of the relatively primitive teleosts (such as trout) on the back near the base of the caudal fin.

 

The skin of a fish must serve many functions. It aids in maintaining the osmotic balance, provides physical protection for the body, is the site of coloration, contains sensory receptors, and, in some fishes, functions in respiration. Mucous glands, which aid in maintaining the water balance and offer protection from bacteria, are extremely numerous in fish skin, especially in cyclostomes and teleosts. Since mucous glands are present in the modern lampreys, it is reasonable to assume that they were present in primitive fishes, such as the ancient Silurian and Devonian agnathans. Protection from abrasion and predation is another function of the fish skin, and dermal (skin) bone arose early in fish evolution in response to this need. It is thought that bone first evolved in skin and only later invaded the cartilaginous areas of the fish’s body, to provide additional support and protection. There is some argument as to which came first, cartilage or bone, and fossil evidence does not settle the question. In any event, dermal bone has played an important part in fish evolution and has different characteristics in different groups of fishes. Several groups are characterized at least in part by the kind of bony scales they possess.

 

Scales have played an important part in the evolution of fishes. Primitive fishes usually had thick bony plates or thick scales in several layers of bone, enamel, and related substances. Modern teleost fishes have scales of bone, which, while still protective, allow much more freedom of motion in the body. A few modern teleosts (some catfishes, sticklebacks, and others) have secondarily acquired bony plates in the skin. Modern and early sharks possessed placoid scales, a relatively primitive type of scale with a toothlike structure, consisting of an outside layer of enamel-like substance (vitrodentine), an inner layer of dentine, and a pulp cavity containing nerves and blood vessels. Primitive bony fishes had thick scales of either the ganoid or the cosmoid type. Cosmoid scales have a hard, enamel-like outer layer, an inner layer of cosmine (a form of dentine), and then a layer of vascular bone (isopedine). In ganoid scales the hard outer layer is different chemically and is called ganoin. Under this is a cosminelike layer and then a vascular bony layer. The thin, translucent bony scales of modern fishes, called cycloid and ctenoid (the latter distinguished by serrations at the edges), lack enameloid and dentine layers.

 

Skin has several other functions in fishes. It is well supplied with nerve endings and presumably receives tactile, thermal, and pain stimuli. Skin is also well supplied with blood vessels. Some fishes breathe in part through the skin, by the exchange of oxygen and carbon dioxide between the surrounding water and numerous small blood vessels near the skin surface.

 

Skin serves as protection through the control of coloration. Fishes exhibit an almost limitless range of colours. The colours often blend closely with the surroundings, effectively hiding the animal. Many fishes use bright colours for territorial advertisement or as recognition marks for other members of their own species, or sometimes for members of other species. Many fishes can change their colour to a greater or lesser degree, by movement of pigment within the pigment cells (chromatophores). Black pigment cells (melanophores), of almost universal occurrence in fishes, are often juxtaposed with other pigment cells. When placed beneath iridocytes or leucophores (bearing the silvery or white pigment guanine), melanophores produce structural colours of blue and green. These colours are often extremely intense, because they are formed by refraction of light through the needlelike crystals of guanine. The blue and green refracted colours are often relatively pure, lacking the red and yellow rays, which have been absorbed by the black pigment (melanin) of the melanophores. Yellow, orange, and red colours are produced by erythrophores, cells containing the appropriate carotenoid pigments. Other colours are produced by combinations of melanophores, erythrophores, and iridocytes.

 

The major portion of the body of most fishes consists of muscles. Most of the mass is trunk musculature, the fin muscles usually being relatively small. The caudal fin is usually the most powerful fin, being moved by the trunk musculature. The body musculature is usually arranged in rows of chevron-shaped segments on each side. Contractions of these segments, each attached to adjacent vertebrae and vertebral processes, bends the body on the vertebral joint, producing successive undulations of the body, passing from the head to the tail, and producing driving strokes of the tail. It is the latter that provides the strong forward movement for most fishes.

 

The digestive system, in a functional sense, starts at the mouth, with the teeth used to capture prey or collect plant foods. Mouth shape and tooth structure vary greatly in fishes, depending on the kind of food normally eaten. Most fishes are predacious, feeding on small invertebrates or other fishes and have simple conical teeth on the jaws, on at least some of the bones of the roof of the mouth, and on special gill arch structures just in front of the esophagus. The latter are throat teeth. Most predacious fishes swallow their prey whole, and the teeth are used for grasping and holding prey, for orienting prey to be swallowed (head first) and for working the prey toward the esophagus. There are a variety of tooth types in fishes. Some fishes, such as sharks and piranhas, have cutting teeth for biting chunks out of their victims. A shark’s tooth, although superficially like that of a piranha, appears in many respects to be a modified scale, while that of the piranha is like that of other bony fishes, consisting of dentine and enamel. Parrot fishes have beaklike mouths with short incisor-like teeth for breaking off coral and have heavy pavementlike throat teeth for crushing the coral. Some catfishes have small brushlike teeth, arranged in rows on the jaws, for scraping plant and animal growth from rocks. Many fishes (such as the Cyprinidae or minnows) have no jaw teeth at all but have very strong throat teeth.

 

Some fishes gather planktonic food by straining it from their gill cavities with numerous elongate stiff rods (gill rakers) anchored by one end to the gill bars. The food collected on these rods is passed to the throat, where it is swallowed. Most fishes have only short gill rakers that help keep food particles from escaping out the mouth cavity into the gill chamber.

 

Once reaching the throat, food enters a short, often greatly distensible esophagus, a simple tube with a muscular wall leading into a stomach. The stomach varies greatly in fishes, depending upon the diet. In most predacious fishes it is a simple straight or curved tube or pouch with a muscular wall and a glandular lining. Food is largely digested there and leaves the stomach in liquid form.

 

Between the stomach and the intestine, ducts enter the digestive tube from the liver and pancreas. The liver is a large, clearly defined organ. The pancreas may be embedded in it, diffused through it, or broken into small parts spread along some of the intestine. The junction between the stomach and the intestine is marked by a muscular valve. Pyloric ceca (blind sacs) occur in some fishes at this junction and have a digestive or absorptive function or both.

 

The intestine itself is quite variable in length, depending upon the fish’s diet. It is short in predacious forms, sometimes no longer than the body cavity, but long in herbivorous forms, being coiled and several times longer than the entire length of the fish in some species of South American catfishes. The intestine is primarily an organ for absorbing nutrients into the bloodstream. The larger its internal surface, the greater its absorptive efficiency, and a spiral valve is one method of increasing its absorption surface.

 

Sharks, rays, chimaeras, lungfishes, surviving chondrosteans, holosteans, and even a few of the more primitive teleosts have a spiral valve or at least traces of it in the intestine. Most modern teleosts have increased the area of the intestinal walls by having numerous folds and villi (fingerlike projections) somewhat like those in humans. Undigested substances are passed to the exterior through the anus in most teleost fishes. In lungfishes, sharks, and rays, it is first passed through the cloaca, a common cavity receiving the intestinal opening and the ducts from the urogenital system.

 

Oxygen and carbon dioxide dissolve in water, and most fishes exchange dissolved oxygen and carbon dioxide in water by means of the gills. The gills lie behind and to the side of the mouth cavity and consist of fleshy filaments supported by the gill arches and filled with blood vessels, which give gills a bright red colour. Water taken in continuously through the mouth passes backward between the gill bars and over the gill filaments, where the exchange of gases takes place. The gills are protected by a gill cover in teleosts and many other fishes but by flaps of skin in sharks, rays, and some of the older fossil fish groups. The blood capillaries in the gill filaments are close to the gill surface to take up oxygen from the water and to give up excess carbon dioxide to the water.

 

Most modern fishes have a hydrostatic (ballast) organ, called the swim bladder, that lies in the body cavity just below the kidney and above the stomach and intestine. It originated as a diverticulum of the digestive canal. In advanced teleosts, especially the acanthopterygians, the bladder has lost its connection with the digestive tract, a condition called physoclistic. The connection has been retained (physostomous) by many relatively primitive teleosts. In several unrelated lines of fishes, the bladder has become specialized as a lung or, at least, as a highly vascularized accessory breathing organ. Some fishes with such accessory organs are obligate air breathers and will drown if denied access to the surface, even in well-oxygenated water. Fishes with a hydrostatic form of swim bladder can control their depth by regulating the amount of gas in the bladder. The gas, mostly oxygen, is secreted into the bladder by special glands, rendering the fish more buoyant; the gas is absorbed into the bloodstream by another special organ, reducing the overall buoyancy and allowing the fish to sink. Some deep-sea fishes may have oils, rather than gas, in the bladder. Other deep-sea and some bottom-living forms have much-reduced swim bladders or have lost the organ entirely.

 

The swim bladder of fishes follows the same developmental pattern as the lungs of land vertebrates. There is no doubt that the two structures have the same historical origin in primitive fishes. More or less intermediate forms still survive among the more primitive types of fishes, such as the lungfishes Lepidosiren and Protopterus.

 

The circulatory, or blood vascular, system consists of the heart, the arteries, the capillaries, and the veins. It is in the capillaries that the interchange of oxygen, carbon dioxide, nutrients, and other substances such as hormones and waste products takes place. The capillaries lead to the veins, which return the venous blood with its waste products to the heart, kidneys, and gills. There are two kinds of capillary beds: those in the gills and those in the rest of the body. The heart, a folded continuous muscular tube with three or four saclike enlargements, undergoes rhythmic contractions and receives venous blood in a sinus venosus. It passes the blood to an auricle and then into a thick muscular pump, the ventricle. From the ventricle the blood goes to a bulbous structure at the base of a ventral aorta just below the gills. The blood passes to the afferent (receiving) arteries of the gill arches and then to the gill capillaries. There waste gases are given off to the environment, and oxygen is absorbed. The oxygenated blood enters efferent (exuant) arteries of the gill arches and then flows into the dorsal aorta. From there blood is distributed to the tissues and organs of the body. One-way valves prevent backflow. The circulation of fishes thus differs from that of the reptiles, birds, and mammals in that oxygenated blood is not returned to the heart prior to distribution to the other parts of the body.

 

The primary excretory organ in fishes, as in other vertebrates, is the kidney. In fishes some excretion also takes place in the digestive tract, skin, and especially the gills (where ammonia is given off). Compared with land vertebrates, fishes have a special problem in maintaining their internal environment at a constant concentration of water and dissolved substances, such as salts. Proper balance of the internal environment (homeostasis) of a fish is in a great part maintained by the excretory system, especially the kidney.

 

The kidney, gills, and skin play an important role in maintaining a fish’s internal environment and checking the effects of osmosis. Marine fishes live in an environment in which the water around them has a greater concentration of salts than they can have inside their body and still maintain life. Freshwater fishes, on the other hand, live in water with a much lower concentration of salts than they require inside their bodies. Osmosis tends to promote the loss of water from the body of a marine fish and absorption of water by that of a freshwater fish. Mucus in the skin tends to slow the process but is not a sufficient barrier to prevent the movement of fluids through the permeable skin. When solutions on two sides of a permeable membrane have different concentrations of dissolved substances, water will pass through the membrane into the more concentrated solution, while the dissolved chemicals move into the area of lower concentration (diffusion).

 

The kidney of freshwater fishes is often larger in relation to body weight than that of marine fishes. In both groups the kidney excretes wastes from the body, but the kidney of freshwater fishes also excretes large amounts of water, counteracting the water absorbed through the skin. Freshwater fishes tend to lose salt to the environment and must replace it. They get some salt from their food, but the gills and skin inside the mouth actively absorb salt from water passed through the mouth. This absorption is performed by special cells capable of moving salts against the diffusion gradient. Freshwater fishes drink very little water and take in little water with their food.

 

Marine fishes must conserve water, and therefore their kidneys excrete little water. To maintain their water balance, marine fishes drink large quantities of seawater, retaining most of the water and excreting the salt. Most nitrogenous waste in marine fishes appears to be secreted by the gills as ammonia. Marine fishes can excrete salt by clusters of special cells (chloride cells) in the gills.

 

There are several teleosts—for example, the salmon—that travel between fresh water and seawater and must adjust to the reversal of osmotic gradients. They adjust their physiological processes by spending time (often surprisingly little time) in the intermediate brackish environment.

 

Marine hagfishes, sharks, and rays have osmotic concentrations in their blood about equal to that of seawater and so do not have to drink water nor perform much physiological work to maintain their osmotic balance. In sharks and rays the osmotic concentration is kept high by retention of urea in the blood. Freshwater sharks have a lowered concentration of urea in the blood.

 

Endocrine glands secrete their products into the bloodstream and body tissues and, along with the central nervous system, control and regulate many kinds of body functions. Cyclostomes have a well-developed endocrine system, and presumably it was well developed in the early Agnatha, ancestral to modern fishes. Although the endocrine system in fishes is similar to that of higher vertebrates, there are numerous differences in detail. The pituitary, the thyroid, the suprarenals, the adrenals, the pancreatic islets, the sex glands (ovaries and testes), the inner wall of the intestine, and the bodies of the ultimobranchial gland make up the endocrine system in fishes. There are some others whose function is not well understood. These organs regulate sexual activity and reproduction, growth, osmotic pressure, general metabolic activities such as the storage of fat and the utilization of foodstuffs, blood pressure, and certain aspects of skin colour. Many of these activities are also controlled in part by the central nervous system, which works with the endocrine system in maintaining the life of a fish. Some parts of the endocrine system are developmentally, and undoubtedly evolutionarily, derived from the nervous system.

 

As in all vertebrates, the nervous system of fishes is the primary mechanism coordinating body activities, as well as integrating these activities in the appropriate manner with stimuli from the environment. The central nervous system, consisting of the brain and spinal cord, is the primary integrating mechanism. The peripheral nervous system, consisting of nerves that connect the brain and spinal cord to various body organs, carries sensory information from special receptor organs such as the eyes, internal ears, nares (sense of smell), taste glands, and others to the integrating centres of the brain and spinal cord. The peripheral nervous system also carries information via different nerve cells from the integrating centres of the brain and spinal cord. This coded information is carried to the various organs and body systems, such as the skeletal muscular system, for appropriate action in response to the original external or internal stimulus. Another branch of the nervous system, the autonomic nervous system, helps to coordinate the activities of many glands and organs and is itself closely connected to the integrating centres of the brain.

 

The brain of the fish is divided into several anatomical and functional parts, all closely interconnected but each serving as the primary centre of integrating particular kinds of responses and activities. Several of these centres or parts are primarily associated with one type of sensory perception, such as sight, hearing, or smell (olfaction).

 

The sense of smell is important in almost all fishes. Certain eels with tiny eyes depend mostly on smell for location of food. The olfactory, or nasal, organ of fishes is located on the dorsal surface of the snout. The lining of the nasal organ has special sensory cells that perceive chemicals dissolved in the water, such as substances from food material, and send sensory information to the brain by way of the first cranial nerve. Odour also serves as an alarm system. Many fishes, especially various species of freshwater minnows, react with alarm to a chemical released from the skin of an injured member of their own species.

 

Many fishes have a well-developed sense of taste, and tiny pitlike taste buds or organs are located not only within their mouth cavities but also over their heads and parts of their body. Catfishes, which often have poor vision, have barbels (“whiskers”) that serve as supplementary taste organs, those around the mouth being actively used to search out food on the bottom. Some species of naturally blind cave fishes are especially well supplied with taste buds, which often cover most of their body surface.

 

Sight is extremely important in most fishes. The eye of a fish is basically like that of all other vertebrates, but the eyes of fishes are extremely varied in structure and adaptation. In general, fishes living in dark and dim water habitats have large eyes, unless they have specialized in some compensatory way so that another sense (such as smell) is dominant, in which case the eyes will often be reduced. Fishes living in brightly lighted shallow waters often will have relatively small but efficient eyes. Cyclostomes have somewhat less elaborate eyes than other fishes, with skin stretched over the eyeball perhaps making their vision somewhat less effective. Most fishes have a spherical lens and accommodate their vision to far or near subjects by moving the lens within the eyeball. A few sharks accommodate by changing the shape of the lens, as in land vertebrates. Those fishes that are heavily dependent upon the eyes have especially strong muscles for accommodation. Most fishes see well, despite the restrictions imposed by frequent turbidity of the water and by light refraction.

 

Fossil evidence suggests that colour vision evolved in fishes more than 300 million years ago, but not all living fishes have retained this ability. Experimental evidence indicates that many shallow-water fishes, if not all, have colour vision and see some colours especially well, but some bottom-dwelling shore fishes live in areas where the water is sufficiently deep to filter out most if not all colours, and these fishes apparently never see colours. When tested in shallow water, they apparently are unable to respond to colour differences.

 

Sound perception and balance are intimately associated senses in a fish. The organs of hearing are entirely internal, located within the skull, on each side of the brain and somewhat behind the eyes. Sound waves, especially those of low frequencies, travel readily through water and impinge directly upon the bones and fluids of the head and body, to be transmitted to the hearing organs. Fishes readily respond to sound; for example, a trout conditioned to escape by the approach of fishermen will take flight upon perceiving footsteps on a stream bank even if it cannot see a fisherman. Compared with humans, however, the range of sound frequencies heard by fishes is greatly restricted. Many fishes communicate with each other by producing sounds in their swim bladders, in their throats by rasping their teeth, and in other ways.

 

A fish or other vertebrate seldom has to rely on a single type of sensory information to determine the nature of the environment around it. A catfish uses taste and touch when examining a food object with its oral barbels. Like most other animals, fishes have many touch receptors over their body surface. Pain and temperature receptors also are present in fishes and presumably produce the same kind of information to a fish as to humans. Fishes react in a negative fashion to stimuli that would be painful to human beings, suggesting that they feel a sensation of pain.

 

An important sensory system in fishes that is absent in other vertebrates (except some amphibians) is the lateral line system. This consists of a series of heavily innervated small canals located in the skin and bone around the eyes, along the lower jaw, over the head, and down the mid-side of the body, where it is associated with the scales. Intermittently along these canals are located tiny sensory organs (pit organs) that apparently detect changes in pressure. The system allows a fish to sense changes in water currents and pressure, thereby helping the fish to orient itself to the various changes that occur in the physical environment.

 

Although a great many fossil fishes have been found and described, they represent a tiny portion of the long and complex evolution of fishes, and knowledge of fish evolution remains relatively fragmentary. In the classification presented in this article, fishlike vertebrates are divided into seven categories, the members of each having a different basic structural organization and different physical and physiological adaptations for the problems presented by the environment. The broad basic pattern has been one of successive replacement of older groups by newer, better-adapted groups. One or a few members of a group evolved a basically more efficient means of feeding, breathing, or swimming or several better ways of living. These better-adapted groups then forced the extinction of members of the older group with which they competed for available food, breeding places, or other necessities of life. As the new fishes became well established, some of them evolved further and adapted to other habitats, where they continued to replace members of the old group already there. The process was repeated until all or almost all members of the old group in a variety of habitats had been replaced by members of the newer evolutionary line.

 

The earliest vertebrate fossils of certain relationships are fragments of dermal armour of jawless fishes (superclass Agnatha, order Heterostraci) from the Upper Ordovician Period in North America, about 450 million years in age. Early Ordovician toothlike fragments from the former Soviet Union are less certainly remains of agnathans. It is uncertain whether the North American jawless fishes inhabited shallow coastal marine waters, where their remains became fossilized, or were freshwater vertebrates washed into coastal deposits by stream action.

 

Jawless fishes probably arose from ancient, small, soft-bodied filter-feeding organisms much like and probably also ancestral to the modern sand-dwelling filter feeders, the Cephalochordata (Amphioxus and its relatives). The body in the ancestral animals was probably stiffened by a notochord. Although a vertebrate origin in fresh water is much debated by paleontologists, it is possible that mobility of the body and protection provided by dermal armour arose in response to streamflow in the freshwater environment and to the need to escape from and resist the clawed invertebrate eurypterids that lived in the same waters. Because of the marine distribution of the surviving primitive chordates, however, many paleontologists doubt that the vertebrates arose in fresh water.

 

Heterostracan remains are next found in what appear to be delta deposits in two North American localities of Silurian age. By the close of the Silurian, about 416 million years ago, European heterostracan remains are found in what appear to be delta or coastal deposits. In the Late Silurian of the Baltic area, lagoon or freshwater deposits yield jawless fishes of the order Osteostraci. Somewhat later in the Silurian from the same region, layers contain fragments of jawed acanthodians, the earliest group of jawed vertebrates, and of jawless fishes. These layers lie between marine beds but appear to be washed out from fresh waters of a coastal region.

 

It is evident, therefore, that by the end of the Silurian both jawed and jawless vertebrates were well established and already must have had a long history of development. Yet paleontologists have remains only of specialized forms that cannot have been the ancestors of the placoderms and bony fishes that appear in the next period, the Devonian. No fossils are known of the more primitive ancestors of the agnathans and acanthodians. The extensive marine beds of the Silurian and those of the Ordovician are essentially void of vertebrate history. It is believed that the ancestors of fishlike vertebrates evolved in upland fresh waters, where whatever few and relatively small fossil beds were made probably have been long since eroded away. Remains of the earliest vertebrates may never be found.

 

By the close of the Silurian, all known orders of jawless vertebrates had evolved, except perhaps the modern cyclostomes, which are without the hard parts that ordinarily are preserved as fossils. Cyclostomes were unknown as fossils until 1968, when a lamprey of modern body structure was reported from the Middle Pennsylvanian of Illinois, in deposits more than 300 million years old. Fossil evidence of the four orders of armoured jawless vertebrates is absent from deposits later than the Devonian. Presumably, these vertebrates became extinct at that time, being replaced by the more efficient and probably more aggressive placoderms, acanthodians, selachians (sharks and relatives), and by early bony fishes. Cyclostomes survived probably because early on they evolved from anaspid agnathans and developed a rasping tonguelike structure and a sucking mouth, enabling them to prey on other fishes. With this way of life they apparently had no competition from other fish groups. Cyclostomes, the hagfishes and lampreys, were once thought to be closely related because of the similarity in their suctorial mouths, but it is now understood that the hagfishes, order Myxiniformes, are the most primitive living chordates, and they are classified separately from the lampreys, order Petromyzontiformes.

 

Early jawless vertebrates probably fed on tiny organisms by filter feeding, as do the larvae of their descendants, the modern lampreys. The gill cavity of the early agnathans was large. It is thought that small organisms taken from the bottom by a nibbling action of the mouth, or more certainly by a sucking action through the mouth, were passed into the gill cavity along with water for breathing. Small organisms then were strained out by the gill apparatus and directed to the food canal. The gill apparatus thus evolved as a feeding, as well as a breathing, structure. The head and gills in the agnathans were protected by a heavy dermal armour; the tail region was free, allowing motion for swimming.

 

Most important for the evolution of fishes and vertebrates in general was the early appearance of bone, cartilage, and enamel-like substance. These materials became modified in later fishes, enabling them to adapt to many aquatic environments and finally even to land. Other basic organs and tissues of the vertebrates—such as the central nervous system, heart, liver, digestive tract, kidney, and circulatory system— undoubtedly were present in the ancestors of the agnathans. In many ways, bone, both external and internal, was the key to vertebrate evolution.

 

The next class of fishes to appear was the Acanthodii, containing the earliest known jawed vertebrates, which arose in the Late Silurian, more than 416 million years ago. The acanthodians declined after the Devonian but lasted into the Early Permian, a little less than 280 million years ago. The first complete specimens appear in Lower Devonian freshwater deposits, but later in the Devonian and Permian some members appear to have been marine. Most were small fishes, not more than 75 cm (approximately 30 inches) in length.

 

We know nothing of the ancestors of the acanthodians. They must have arisen from some jawless vertebrate, probably in fresh water. They appear to have been active swimmers with almost no head armour but with large eyes, indicating that they depended heavily on vision. Perhaps they preyed on invertebrates. The rows of spines and spinelike fins between the pectoral and pelvic fins give some credence to the idea that paired fins arose from “fin folds” along the body sides.

 

The relationships of the acanthodians to other jawed vertebrates are obscure. They possess features found in both sharks and bony fishes. They are like early bony fishes in possessing ganoidlike scales and a partially ossified internal skeleton. Certain aspects of the jaw appear to be more like those of bony fishes than sharks, but the bony fin spines and certain aspects of the gill apparatus would seem to favour relationships with early sharks. Acanthodians do not seem particularly close to the Placodermi, although, like the placoderms, they apparently possessed less efficient tooth replacement and tooth structure than the sharks and the bony fishes, possibly one reason for their subsequent extinction.

Fish, any of approximately 34,000 species of vertebrate animals (phylum Chordata) found in the fresh and salt waters of the world. Living species range from the primitive jawless lampreys and hagfishes through the cartilaginous sharks, skates, and rays to the abundant and diverse bony fishes. Most fish species are cold-blooded; however, one species, the opah (Lampris guttatus), is warm-blooded.

 

The term fish is applied to a variety of vertebrates of several evolutionary lines. It describes a life-form rather than a taxonomic group. As members of the phylum Chordata, fish share certain features with other vertebrates. These features are gill slits at some point in the life cycle, a notochord, or skeletal supporting rod, a dorsal hollow nerve cord, and a tail. Living fishes represent some five classes, which are as distinct from one another as are the four classes of familiar air-breathing animals—amphibians, reptiles, birds, and mammals. For example, the jawless fishes (Agnatha) have gills in pouches and lack limb girdles. Extant agnathans are the lampreys and the hagfishes. As the name implies, the skeletons of fishes of the class Chondrichthyes (from chondr, “cartilage,” and ichthyes, “fish”) are made entirely of cartilage. Modern fish of this class lack a swim bladder, and their scales and teeth are made up of the same placoid material. Sharks, skates, and rays are examples of cartilaginous fishes. The bony fishes are by far the largest class. Examples range from the tiny seahorse to the 450-kg (1,000-pound) blue marlin, from the flattened soles and flounders to the boxy puffers and ocean sunfishes. Unlike the scales of the cartilaginous fishes, those of bony fishes, when present, grow throughout life and are made up of thin overlapping plates of bone. Bony fishes also have an operculum that covers the gill slits.

 

The study of fishes, the science of ichthyology, is of broad importance. Fishes are of interest to humans for many reasons, the most important being their relationship with and dependence on the environment. A more obvious reason for interest in fishes is their role as a moderate but important part of the world’s food supply. This resource, once thought unlimited, is now realized to be finite and in delicate balance with the biological, chemical, and physical factors of the aquatic environment. Overfishing, pollution, and alteration of the environment are the chief enemies of proper fisheries management, both in fresh waters and in the ocean. (For a detailed discussion of the technology and economics of fisheries, see commercial fishing.) Another practical reason for studying fishes is their use in disease control. As predators on mosquito larvae, they help curb malaria and other mosquito-borne diseases.

 

Fishes are valuable laboratory animals in many aspects of medical and biological research. For example, the readiness of many fishes to acclimate to captivity has allowed biologists to study behaviour, physiology, and even ecology under relatively natural conditions. Fishes have been especially important in the study of animal behaviour, where research on fishes has provided a broad base for the understanding of the more flexible behaviour of the higher vertebrates. The zebra fish is used as a model in studies of gene expression.

 

There are aesthetic and recreational reasons for an interest in fishes. Millions of people keep live fishes in home aquariums for the simple pleasure of observing the beauty and behaviour of animals otherwise unfamiliar to them. Aquarium fishes provide a personal challenge to many aquarists, allowing them to test their ability to keep a small section of the natural environment in their homes. Sportfishing is another way of enjoying the natural environment, also indulged in by millions of people every year. Interest in aquarium fishes and sportfishing supports multimillion-dollar industries throughout the world.

 

Fishes have been in existence for more than 450 million years, during which time they have evolved repeatedly to fit into almost every conceivable type of aquatic habitat. In a sense, land vertebrates are simply highly modified fishes: when fishes colonized the land habitat, they became tetrapod (four-legged) land vertebrates. The popular conception of a fish as a slippery, streamlined aquatic animal that possesses fins and breathes by gills applies to many fishes, but far more fishes deviate from that conception than conform to it. For example, the body is elongate in many forms and greatly shortened in others; the body is flattened in some (principally in bottom-dwelling fishes) and laterally compressed in many others; the fins may be elaborately extended, forming intricate shapes, or they may be reduced or even lost; and the positions of the mouth, eyes, nostrils, and gill openings vary widely. Air breathers have appeared in several evolutionary lines.

 

Many fishes are cryptically coloured and shaped, closely matching their respective environments; others are among the most brilliantly coloured of all organisms, with a wide range of hues, often of striking intensity, on a single individual. The brilliance of pigments may be enhanced by the surface structure of the fish, so that it almost seems to glow. A number of unrelated fishes have actual light-producing organs. Many fishes are able to alter their coloration—some for the purpose of camouflage, others for the enhancement of behavioral signals.

 

Fishes range in adult length from less than 10 mm (0.4 inch) to more than 20 metres (60 feet) and in weight from about 1.5 grams (less than 0.06 ounce) to many thousands of kilograms. Some live in shallow thermal springs at temperatures slightly above 42 °C (100 °F), others in cold Arctic seas a few degrees below 0 °C (32 °F) or in cold deep waters more than 4,000 metres (13,100 feet) beneath the ocean surface. The structural and, especially, the physiological adaptations for life at such extremes are relatively poorly known and provide the scientifically curious with great incentive for study.

 

Almost all natural bodies of water bear fish life, the exceptions being very hot thermal ponds and extremely salt-alkaline lakes, such as the Dead Sea in Asia and the Great Salt Lake in North America. The present distribution of fishes is a result of the geological history and development of Earth as well as the ability of fishes to undergo evolutionary change and to adapt to the available habitats. Fishes may be seen to be distributed according to habitat and according to geographical area. Major habitat differences are marine and freshwater. For the most part, the fishes in a marine habitat differ from those in a freshwater habitat, even in adjacent areas, but some, such as the salmon, migrate from one to the other. The freshwater habitats may be seen to be of many kinds. Fishes found in mountain torrents, Arctic lakes, tropical lakes, temperate streams, and tropical rivers will all differ from each other, both in obvious gross structure and in physiological attributes. Even in closely adjacent habitats where, for example, a tropical mountain torrent enters a lowland stream, the fish fauna will differ. The marine habitats can be divided into deep ocean floors (benthic), mid-water oceanic (bathypelagic), surface oceanic (pelagic), rocky coast, sandy coast, muddy shores, bays, estuaries, and others. Also, for example, rocky coastal shores in tropical and temperate regions will have different fish faunas, even when such habitats occur along the same coastline.

 

Although much is known about the present geographical distribution of fishes, far less is known about how that distribution came about. Many parts of the fish fauna of the fresh waters of North America and Eurasia are related and undoubtedly have a common origin. The faunas of Africa and South America are related, extremely old, and probably an expression of the drifting apart of the two continents. The fauna of southern Asia is related to that of Central Asia, and some of it appears to have entered Africa. The extremely large shore-fish faunas of the Indian and tropical Pacific oceans comprise a related complex, but the tropical shore fauna of the Atlantic, although containing Indo-Pacific components, is relatively limited and probably younger. The Arctic and Antarctic marine faunas are quite different from each other. The shore fauna of the North Pacific is quite distinct, and that of the North Atlantic more limited and probably younger. Pelagic oceanic fishes, especially those in deep waters, are similar the world over, showing little geographical isolation in terms of family groups. The deep oceanic habitat is very much the same throughout the world, but species differences do exist, showing geographical areas determined by oceanic currents and water masses.

 

All aspects of the life of a fish are closely correlated with adaptation to the total environment, physical, chemical, and biological. In studies, all the interdependent aspects of fish, such as behaviour, locomotion, reproduction, and physical and physiological characteristics, must be taken into account.

 

Correlated with their adaptation to an extremely wide variety of habitats is the extremely wide variety of life cycles that fishes display. The great majority hatch from relatively small eggs a few days to several weeks or more after the eggs are scattered in the water. Newly hatched young are still partially undeveloped and are called larvae until body structures such as fins, skeleton, and some organs are fully formed. Larval life is often very short, usually less than a few weeks, but it can be very long, some lampreys continuing as larvae for at least five years. Young and larval fishes, before reaching sexual maturity, must grow considerably, and their small size and other factors often dictate that they live in a habitat different than that of the adults. For example, most tropical marine shore fishes have pelagic larvae. Larval food also is different, and larval fishes often live in shallow waters, where they may be less exposed to predators.

 

After a fish reaches adult size, the length of its life is subject to many factors, such as innate rates of aging, predation pressure, and the nature of the local climate. The longevity of a species in the protected environment of an aquarium may have nothing to do with how long members of that species live in the wild. Many small fishes live only one to three years at the most. In some species, however, individuals may live as long as 10 or 20 or even 100 years.

 

Fish behaviour is a complicated and varied subject. As in almost all animals with a central nervous system, the nature of a response of an individual fish to stimuli from its environment depends upon the inherited characteristics of its nervous system, on what it has learned from past experience, and on the nature of the stimuli. Compared with the variety of human responses, however, that of a fish is stereotyped, not subject to much modification by “thought” or learning, and investigators must guard against anthropomorphic interpretations of fish behaviour.

 

Fishes perceive the world around them by the usual senses of sight, smell, hearing, touch, and taste and by special lateral line water-current detectors. In the few fishes that generate electric fields, a process that might best be called electrolocation aids in perception. One or another of these senses often is emphasized at the expense of others, depending upon the fish’s other adaptations. In fishes with large eyes, the sense of smell may be reduced; others, with small eyes, hunt and feed primarily by smell (such as some eels).

 

Specialized behaviour is primarily concerned with the three most important activities in the fish’s life: feeding, reproduction, and escape from enemies. Schooling behaviour of sardines on the high seas, for instance, is largely a protective device to avoid enemies, but it is also associated with and modified by their breeding and feeding requirements. Predatory fishes are often solitary, lying in wait to dart suddenly after their prey, a kind of locomotion impossible for beaked parrot fishes, which feed on coral, swimming in small groups from one coral head to the next. In addition, some predatory fishes that inhabit pelagic environments, such as tunas, often school.

 

Sleep in fishes, all of which lack true eyelids, consists of a seemingly listless state in which the fish maintains its balance but moves slowly. If attacked or disturbed, most can dart away. A few kinds of fishes lie on the bottom to sleep. Most catfishes, some loaches, and some eels and electric fishes are strictly nocturnal, being active and hunting for food during the night and retiring during the day to holes, thick vegetation, or other protective parts of the environment.

 

Communication between members of a species or between members of two or more species often is extremely important, especially in breeding behaviour (see below Reproduction). The mode of communication may be visual, as between the small so-called cleaner fish and a large fish of a very different species. The larger fish often allows the cleaner to enter its mouth to remove gill parasites. The cleaner is recognized by its distinctive colour and actions and therefore is not eaten, even if the larger fish is normally a predator. Communication is often chemical, signals being sent by specific chemicals called pheromones.

 

Many fishes have a streamlined body and swim freely in open water. Fish locomotion is closely correlated with habitat and ecological niche (the general position of the animal to its environment).

 

Many fishes in both marine and fresh waters swim at the surface and have mouths adapted to feed best (and sometimes only) at the surface. Often such fishes are long and slender, able to dart at surface insects or at other surface fishes and in turn to dart away from predators; needlefishes, halfbeaks, and topminnows (such as killifish and mosquito fish) are good examples. Oceanic flying fishes escape their predators by gathering speed above the water surface, with the lower lobe of the tail providing thrust in the water. They then glide hundreds of yards on enlarged, winglike pectoral and pelvic fins. South American freshwater flying fishes escape their enemies by jumping and propelling their strongly keeled bodies out of the water.

 

So-called mid-water swimmers, the most common type of fish, are of many kinds and live in many habitats. The powerful fusiform tunas and the trouts, for example, are adapted for strong, fast swimming, the tunas to capture prey speedily in the open ocean and the trouts to cope with the swift currents of streams and rivers. The trout body form is well adapted to many habitats. Fishes that live in relatively quiet waters such as bays or lake shores or slow rivers usually are not strong, fast swimmers but are capable of short, quick bursts of speed to escape a predator. Many of these fishes have their sides flattened, examples being the sunfish and the freshwater angelfish of aquarists. Fish associated with the bottom or substrate usually are slow swimmers. Open-water plankton-feeding fishes almost always remain fusiform and are capable of rapid, strong movement (for example, sardines and herrings of the open ocean and also many small minnows of streams and lakes).

 

Bottom-living fishes are of many kinds and have undergone many types of modification of their body shape and swimming habits. Rays, which evolved from strong-swimming mid-water sharks, usually stay close to the bottom and move by undulating their large pectoral fins. Flounders live in a similar habitat and move over the bottom by undulating the entire body. Many bottom fishes dart from place to place, resting on the bottom between movements, a motion common in gobies. One goby relative, the mudskipper, has taken to living at the edge of pools along the shore of muddy mangrove swamps. It escapes its enemies by flipping rapidly over the mud, out of the water. Some catfishes, synbranchid eels, the so-called climbing perch, and a few other fishes venture out over damp ground to find more promising waters than those that they left. They move by wriggling their bodies, sometimes using strong pectoral fins; most have accessory air-breathing organs. Many bottom-dwelling fishes live in mud holes or rocky crevices. Marine eels and gobies commonly are found in such habitats and for the most part venture far beyond their cavelike homes. Some bottom dwellers, such as the clingfishes (Gobiesocidae), have developed powerful adhesive disks that enable them to remain in place on the substrate in areas such as rocky coasts, where the action of the waves is great.

 

The methods of reproduction in fishes are varied, but most fishes lay a large number of small eggs, fertilized and scattered outside of the body. The eggs of pelagic fishes usually remain suspended in the open water. Many shore and freshwater fishes lay eggs on the bottom or among plants. Some have adhesive eggs. The mortality of the young and especially of the eggs is very high, and often only a few individuals grow to maturity out of hundreds, thousands, and in some cases millions of eggs laid.

 

Males produce sperm, usually as a milky white substance called milt, in two (sometimes one) testes within the body cavity. In bony fishes a sperm duct leads from each testis to a urogenital opening behind the vent or anus. In sharks and rays and in cyclostomes the duct leads to a cloaca. Sometimes the pelvic fins are modified to help transmit the milt to the eggs at the female’s vent or on the substrate where the female has placed them. Sometimes accessory organs are used to fertilize females internally—for example, the claspers of many sharks and rays.

 

In the females the eggs are formed in two ovaries (sometimes only one) and pass through the ovaries to the urogenital opening and to the outside. In some fishes the eggs are fertilized internally but are shed before development takes place. Members of about a dozen families each of bony fishes (teleosts) and sharks bear live young. Many skates and rays also bear live young. In some bony fishes the eggs simply develop within the female, the young emerging when the eggs hatch (ovoviviparous). Others develop within the ovary and are nourished by ovarian tissues after hatching (viviparous). There are also other methods utilized by fishes to nourish young within the female. In all live-bearers the young are born at a relatively large size and are few in number. In one family of primarily marine fishes, the surfperches from the Pacific coast of North America, Japan, and Korea, the males of at least one species are born sexually mature, although they are not fully grown.

 

Some fishes are hermaphroditic—an individual producing both sperm and eggs, usually at different stages of its life. Self-fertilization, however, is probably rare.

 

Successful reproduction and, in many cases, defense of the eggs and the young are assured by rather stereotypical but often elaborate courtship and parental behaviour, either by the male or the female or both. Some fishes prepare nests by hollowing out depressions in the sand bottom (cichlids, for example), build nests with plant materials and sticky threads excreted by the kidneys (sticklebacks), or blow a cluster of mucus-covered bubbles at the water surface (gouramis). The eggs are laid in these structures. Some varieties of cichlids and catfishes incubate eggs in their mouths.

 

Some fishes, such as salmon, undergo long migrations from the ocean and up large rivers to spawn in the gravel beds where they themselves hatched (anadromous fishes). Some, such as the freshwater eels (family Anguillidae), live and grow to maturity in fresh water and migrate to the sea to spawn (catadromous fishes). Other fishes undertake shorter migrations from lakes into streams, within the ocean, or enter spawning habitats that they do not ordinarily occupy in other ways.

 

The basic structure and function of the fish body are similar to those of all other vertebrates. The usual four types of tissues are present: surface or epithelial, connective (bone, cartilage, and fibrous tissues, as well as their derivative, blood), nerve, and muscle tissues. In addition, the fish’s organs and organ systems parallel those of other vertebrates.

 

The typical fish body is streamlined and spindle-shaped, with an anterior head, a gill apparatus, and a heart, the latter lying in the midline just below the gill chamber. The body cavity, containing the vital organs, is situated behind the head in the lower anterior part of the body. The anus usually marks the posterior termination of the body cavity and most often occurs just in front of the base of the anal fin. The spinal cord and vertebral column continue from the posterior part of the head to the base of the tail fin, passing dorsal to the body cavity and through the caudal (tail) region behind the body cavity. Most of the body is of muscular tissue, a high proportion of which is necessitated by swimming. In the course of evolution this basic body plan has been modified repeatedly into the many varieties of fish shapes that exist today.

 

The skeleton forms an integral part of the fish’s locomotion system, as well as serving to protect vital parts. The internal skeleton consists of the skull bones (except for the roofing bones of the head, which are really part of the external skeleton), the vertebral column, and the fin supports (fin rays). The fin supports are derived from the external skeleton but will be treated here because of their close functional relationship to the internal skeleton. The internal skeleton of cyclostomes, sharks, and rays is of cartilage; that of many fossil groups and some primitive living fishes is mostly of cartilage but may include some bone. In place of the vertebral column, the earliest vertebrates had a fully developed notochord, a flexible stiff rod of viscous cells surrounded by a strong fibrous sheath. During the evolution of modern fishes the rod was replaced in part by cartilage and then by ossified cartilage. Sharks and rays retain a cartilaginous vertebral column; bony fishes have spool-shaped vertebrae that in the more primitive living forms only partially replace the notochord. The skull, including the gill arches and jaws of bony fishes, is fully, or at least partially, ossified. That of sharks and rays remains cartilaginous, at times partially replaced by calcium deposits but never by true bone.

 

The supportive elements of the fins (basal or radial bones or both) have changed greatly during fish evolution. Some of these changes are described in the section below (Evolution and paleontology). Most fishes possess a single dorsal fin on the midline of the back. Many have two and a few have three dorsal fins. The other fins are the single tail and anal fins and paired pelvic and pectoral fins. A small fin, the adipose fin, with hairlike fin rays, occurs in many of the relatively primitive teleosts (such as trout) on the back near the base of the caudal fin.

 

The skin of a fish must serve many functions. It aids in maintaining the osmotic balance, provides physical protection for the body, is the site of coloration, contains sensory receptors, and, in some fishes, functions in respiration. Mucous glands, which aid in maintaining the water balance and offer protection from bacteria, are extremely numerous in fish skin, especially in cyclostomes and teleosts. Since mucous glands are present in the modern lampreys, it is reasonable to assume that they were present in primitive fishes, such as the ancient Silurian and Devonian agnathans. Protection from abrasion and predation is another function of the fish skin, and dermal (skin) bone arose early in fish evolution in response to this need. It is thought that bone first evolved in skin and only later invaded the cartilaginous areas of the fish’s body, to provide additional support and protection. There is some argument as to which came first, cartilage or bone, and fossil evidence does not settle the question. In any event, dermal bone has played an important part in fish evolution and has different characteristics in different groups of fishes. Several groups are characterized at least in part by the kind of bony scales they possess.

 

Scales have played an important part in the evolution of fishes. Primitive fishes usually had thick bony plates or thick scales in several layers of bone, enamel, and related substances. Modern teleost fishes have scales of bone, which, while still protective, allow much more freedom of motion in the body. A few modern teleosts (some catfishes, sticklebacks, and others) have secondarily acquired bony plates in the skin. Modern and early sharks possessed placoid scales, a relatively primitive type of scale with a toothlike structure, consisting of an outside layer of enamel-like substance (vitrodentine), an inner layer of dentine, and a pulp cavity containing nerves and blood vessels. Primitive bony fishes had thick scales of either the ganoid or the cosmoid type. Cosmoid scales have a hard, enamel-like outer layer, an inner layer of cosmine (a form of dentine), and then a layer of vascular bone (isopedine). In ganoid scales the hard outer layer is different chemically and is called ganoin. Under this is a cosminelike layer and then a vascular bony layer. The thin, translucent bony scales of modern fishes, called cycloid and ctenoid (the latter distinguished by serrations at the edges), lack enameloid and dentine layers.

 

Skin has several other functions in fishes. It is well supplied with nerve endings and presumably receives tactile, thermal, and pain stimuli. Skin is also well supplied with blood vessels. Some fishes breathe in part through the skin, by the exchange of oxygen and carbon dioxide between the surrounding water and numerous small blood vessels near the skin surface.

 

Skin serves as protection through the control of coloration. Fishes exhibit an almost limitless range of colours. The colours often blend closely with the surroundings, effectively hiding the animal. Many fishes use bright colours for territorial advertisement or as recognition marks for other members of their own species, or sometimes for members of other species. Many fishes can change their colour to a greater or lesser degree, by movement of pigment within the pigment cells (chromatophores). Black pigment cells (melanophores), of almost universal occurrence in fishes, are often juxtaposed with other pigment cells. When placed beneath iridocytes or leucophores (bearing the silvery or white pigment guanine), melanophores produce structural colours of blue and green. These colours are often extremely intense, because they are formed by refraction of light through the needlelike crystals of guanine. The blue and green refracted colours are often relatively pure, lacking the red and yellow rays, which have been absorbed by the black pigment (melanin) of the melanophores. Yellow, orange, and red colours are produced by erythrophores, cells containing the appropriate carotenoid pigments. Other colours are produced by combinations of melanophores, erythrophores, and iridocytes.

 

The major portion of the body of most fishes consists of muscles. Most of the mass is trunk musculature, the fin muscles usually being relatively small. The caudal fin is usually the most powerful fin, being moved by the trunk musculature. The body musculature is usually arranged in rows of chevron-shaped segments on each side. Contractions of these segments, each attached to adjacent vertebrae and vertebral processes, bends the body on the vertebral joint, producing successive undulations of the body, passing from the head to the tail, and producing driving strokes of the tail. It is the latter that provides the strong forward movement for most fishes.

 

The digestive system, in a functional sense, starts at the mouth, with the teeth used to capture prey or collect plant foods. Mouth shape and tooth structure vary greatly in fishes, depending on the kind of food normally eaten. Most fishes are predacious, feeding on small invertebrates or other fishes and have simple conical teeth on the jaws, on at least some of the bones of the roof of the mouth, and on special gill arch structures just in front of the esophagus. The latter are throat teeth. Most predacious fishes swallow their prey whole, and the teeth are used for grasping and holding prey, for orienting prey to be swallowed (head first) and for working the prey toward the esophagus. There are a variety of tooth types in fishes. Some fishes, such as sharks and piranhas, have cutting teeth for biting chunks out of their victims. A shark’s tooth, although superficially like that of a piranha, appears in many respects to be a modified scale, while that of the piranha is like that of other bony fishes, consisting of dentine and enamel. Parrot fishes have beaklike mouths with short incisor-like teeth for breaking off coral and have heavy pavementlike throat teeth for crushing the coral. Some catfishes have small brushlike teeth, arranged in rows on the jaws, for scraping plant and animal growth from rocks. Many fishes (such as the Cyprinidae or minnows) have no jaw teeth at all but have very strong throat teeth.

 

Some fishes gather planktonic food by straining it from their gill cavities with numerous elongate stiff rods (gill rakers) anchored by one end to the gill bars. The food collected on these rods is passed to the throat, where it is swallowed. Most fishes have only short gill rakers that help keep food particles from escaping out the mouth cavity into the gill chamber.

 

Once reaching the throat, food enters a short, often greatly distensible esophagus, a simple tube with a muscular wall leading into a stomach. The stomach varies greatly in fishes, depending upon the diet. In most predacious fishes it is a simple straight or curved tube or pouch with a muscular wall and a glandular lining. Food is largely digested there and leaves the stomach in liquid form.

 

Between the stomach and the intestine, ducts enter the digestive tube from the liver and pancreas. The liver is a large, clearly defined organ. The pancreas may be embedded in it, diffused through it, or broken into small parts spread along some of the intestine. The junction between the stomach and the intestine is marked by a muscular valve. Pyloric ceca (blind sacs) occur in some fishes at this junction and have a digestive or absorptive function or both.

 

The intestine itself is quite variable in length, depending upon the fish’s diet. It is short in predacious forms, sometimes no longer than the body cavity, but long in herbivorous forms, being coiled and several times longer than the entire length of the fish in some species of South American catfishes. The intestine is primarily an organ for absorbing nutrients into the bloodstream. The larger its internal surface, the greater its absorptive efficiency, and a spiral valve is one method of increasing its absorption surface.

 

Sharks, rays, chimaeras, lungfishes, surviving chondrosteans, holosteans, and even a few of the more primitive teleosts have a spiral valve or at least traces of it in the intestine. Most modern teleosts have increased the area of the intestinal walls by having numerous folds and villi (fingerlike projections) somewhat like those in humans. Undigested substances are passed to the exterior through the anus in most teleost fishes. In lungfishes, sharks, and rays, it is first passed through the cloaca, a common cavity receiving the intestinal opening and the ducts from the urogenital system.

 

Oxygen and carbon dioxide dissolve in water, and most fishes exchange dissolved oxygen and carbon dioxide in water by means of the gills. The gills lie behind and to the side of the mouth cavity and consist of fleshy filaments supported by the gill arches and filled with blood vessels, which give gills a bright red colour. Water taken in continuously through the mouth passes backward between the gill bars and over the gill filaments, where the exchange of gases takes place. The gills are protected by a gill cover in teleosts and many other fishes but by flaps of skin in sharks, rays, and some of the older fossil fish groups. The blood capillaries in the gill filaments are close to the gill surface to take up oxygen from the water and to give up excess carbon dioxide to the water.

 

Most modern fishes have a hydrostatic (ballast) organ, called the swim bladder, that lies in the body cavity just below the kidney and above the stomach and intestine. It originated as a diverticulum of the digestive canal. In advanced teleosts, especially the acanthopterygians, the bladder has lost its connection with the digestive tract, a condition called physoclistic. The connection has been retained (physostomous) by many relatively primitive teleosts. In several unrelated lines of fishes, the bladder has become specialized as a lung or, at least, as a highly vascularized accessory breathing organ. Some fishes with such accessory organs are obligate air breathers and will drown if denied access to the surface, even in well-oxygenated water. Fishes with a hydrostatic form of swim bladder can control their depth by regulating the amount of gas in the bladder. The gas, mostly oxygen, is secreted into the bladder by special glands, rendering the fish more buoyant; the gas is absorbed into the bloodstream by another special organ, reducing the overall buoyancy and allowing the fish to sink. Some deep-sea fishes may have oils, rather than gas, in the bladder. Other deep-sea and some bottom-living forms have much-reduced swim bladders or have lost the organ entirely.

 

The swim bladder of fishes follows the same developmental pattern as the lungs of land vertebrates. There is no doubt that the two structures have the same historical origin in primitive fishes. More or less intermediate forms still survive among the more primitive types of fishes, such as the lungfishes Lepidosiren and Protopterus.

 

The circulatory, or blood vascular, system consists of the heart, the arteries, the capillaries, and the veins. It is in the capillaries that the interchange of oxygen, carbon dioxide, nutrients, and other substances such as hormones and waste products takes place. The capillaries lead to the veins, which return the venous blood with its waste products to the heart, kidneys, and gills. There are two kinds of capillary beds: those in the gills and those in the rest of the body. The heart, a folded continuous muscular tube with three or four saclike enlargements, undergoes rhythmic contractions and receives venous blood in a sinus venosus. It passes the blood to an auricle and then into a thick muscular pump, the ventricle. From the ventricle the blood goes to a bulbous structure at the base of a ventral aorta just below the gills. The blood passes to the afferent (receiving) arteries of the gill arches and then to the gill capillaries. There waste gases are given off to the environment, and oxygen is absorbed. The oxygenated blood enters efferent (exuant) arteries of the gill arches and then flows into the dorsal aorta. From there blood is distributed to the tissues and organs of the body. One-way valves prevent backflow. The circulation of fishes thus differs from that of the reptiles, birds, and mammals in that oxygenated blood is not returned to the heart prior to distribution to the other parts of the body.

 

The primary excretory organ in fishes, as in other vertebrates, is the kidney. In fishes some excretion also takes place in the digestive tract, skin, and especially the gills (where ammonia is given off). Compared with land vertebrates, fishes have a special problem in maintaining their internal environment at a constant concentration of water and dissolved substances, such as salts. Proper balance of the internal environment (homeostasis) of a fish is in a great part maintained by the excretory system, especially the kidney.

 

The kidney, gills, and skin play an important role in maintaining a fish’s internal environment and checking the effects of osmosis. Marine fishes live in an environment in which the water around them has a greater concentration of salts than they can have inside their body and still maintain life. Freshwater fishes, on the other hand, live in water with a much lower concentration of salts than they require inside their bodies. Osmosis tends to promote the loss of water from the body of a marine fish and absorption of water by that of a freshwater fish. Mucus in the skin tends to slow the process but is not a sufficient barrier to prevent the movement of fluids through the permeable skin. When solutions on two sides of a permeable membrane have different concentrations of dissolved substances, water will pass through the membrane into the more concentrated solution, while the dissolved chemicals move into the area of lower concentration (diffusion).

 

The kidney of freshwater fishes is often larger in relation to body weight than that of marine fishes. In both groups the kidney excretes wastes from the body, but the kidney of freshwater fishes also excretes large amounts of water, counteracting the water absorbed through the skin. Freshwater fishes tend to lose salt to the environment and must replace it. They get some salt from their food, but the gills and skin inside the mouth actively absorb salt from water passed through the mouth. This absorption is performed by special cells capable of moving salts against the diffusion gradient. Freshwater fishes drink very little water and take in little water with their food.

 

Marine fishes must conserve water, and therefore their kidneys excrete little water. To maintain their water balance, marine fishes drink large quantities of seawater, retaining most of the water and excreting the salt. Most nitrogenous waste in marine fishes appears to be secreted by the gills as ammonia. Marine fishes can excrete salt by clusters of special cells (chloride cells) in the gills.

 

There are several teleosts—for example, the salmon—that travel between fresh water and seawater and must adjust to the reversal of osmotic gradients. They adjust their physiological processes by spending time (often surprisingly little time) in the intermediate brackish environment.

 

Marine hagfishes, sharks, and rays have osmotic concentrations in their blood about equal to that of seawater and so do not have to drink water nor perform much physiological work to maintain their osmotic balance. In sharks and rays the osmotic concentration is kept high by retention of urea in the blood. Freshwater sharks have a lowered concentration of urea in the blood.

 

Endocrine glands secrete their products into the bloodstream and body tissues and, along with the central nervous system, control and regulate many kinds of body functions. Cyclostomes have a well-developed endocrine system, and presumably it was well developed in the early Agnatha, ancestral to modern fishes. Although the endocrine system in fishes is similar to that of higher vertebrates, there are numerous differences in detail. The pituitary, the thyroid, the suprarenals, the adrenals, the pancreatic islets, the sex glands (ovaries and testes), the inner wall of the intestine, and the bodies of the ultimobranchial gland make up the endocrine system in fishes. There are some others whose function is not well understood. These organs regulate sexual activity and reproduction, growth, osmotic pressure, general metabolic activities such as the storage of fat and the utilization of foodstuffs, blood pressure, and certain aspects of skin colour. Many of these activities are also controlled in part by the central nervous system, which works with the endocrine system in maintaining the life of a fish. Some parts of the endocrine system are developmentally, and undoubtedly evolutionarily, derived from the nervous system.

 

As in all vertebrates, the nervous system of fishes is the primary mechanism coordinating body activities, as well as integrating these activities in the appropriate manner with stimuli from the environment. The central nervous system, consisting of the brain and spinal cord, is the primary integrating mechanism. The peripheral nervous system, consisting of nerves that connect the brain and spinal cord to various body organs, carries sensory information from special receptor organs such as the eyes, internal ears, nares (sense of smell), taste glands, and others to the integrating centres of the brain and spinal cord. The peripheral nervous system also carries information via different nerve cells from the integrating centres of the brain and spinal cord. This coded information is carried to the various organs and body systems, such as the skeletal muscular system, for appropriate action in response to the original external or internal stimulus. Another branch of the nervous system, the autonomic nervous system, helps to coordinate the activities of many glands and organs and is itself closely connected to the integrating centres of the brain.

 

The brain of the fish is divided into several anatomical and functional parts, all closely interconnected but each serving as the primary centre of integrating particular kinds of responses and activities. Several of these centres or parts are primarily associated with one type of sensory perception, such as sight, hearing, or smell (olfaction).

 

The sense of smell is important in almost all fishes. Certain eels with tiny eyes depend mostly on smell for location of food. The olfactory, or nasal, organ of fishes is located on the dorsal surface of the snout. The lining of the nasal organ has special sensory cells that perceive chemicals dissolved in the water, such as substances from food material, and send sensory information to the brain by way of the first cranial nerve. Odour also serves as an alarm system. Many fishes, especially various species of freshwater minnows, react with alarm to a chemical released from the skin of an injured member of their own species.

 

Many fishes have a well-developed sense of taste, and tiny pitlike taste buds or organs are located not only within their mouth cavities but also over their heads and parts of their body. Catfishes, which often have poor vision, have barbels (“whiskers”) that serve as supplementary taste organs, those around the mouth being actively used to search out food on the bottom. Some species of naturally blind cave fishes are especially well supplied with taste buds, which often cover most of their body surface.

 

Sight is extremely important in most fishes. The eye of a fish is basically like that of all other vertebrates, but the eyes of fishes are extremely varied in structure and adaptation. In general, fishes living in dark and dim water habitats have large eyes, unless they have specialized in some compensatory way so that another sense (such as smell) is dominant, in which case the eyes will often be reduced. Fishes living in brightly lighted shallow waters often will have relatively small but efficient eyes. Cyclostomes have somewhat less elaborate eyes than other fishes, with skin stretched over the eyeball perhaps making their vision somewhat less effective. Most fishes have a spherical lens and accommodate their vision to far or near subjects by moving the lens within the eyeball. A few sharks accommodate by changing the shape of the lens, as in land vertebrates. Those fishes that are heavily dependent upon the eyes have especially strong muscles for accommodation. Most fishes see well, despite the restrictions imposed by frequent turbidity of the water and by light refraction.

 

Fossil evidence suggests that colour vision evolved in fishes more than 300 million years ago, but not all living fishes have retained this ability. Experimental evidence indicates that many shallow-water fishes, if not all, have colour vision and see some colours especially well, but some bottom-dwelling shore fishes live in areas where the water is sufficiently deep to filter out most if not all colours, and these fishes apparently never see colours. When tested in shallow water, they apparently are unable to respond to colour differences.

 

Sound perception and balance are intimately associated senses in a fish. The organs of hearing are entirely internal, located within the skull, on each side of the brain and somewhat behind the eyes. Sound waves, especially those of low frequencies, travel readily through water and impinge directly upon the bones and fluids of the head and body, to be transmitted to the hearing organs. Fishes readily respond to sound; for example, a trout conditioned to escape by the approach of fishermen will take flight upon perceiving footsteps on a stream bank even if it cannot see a fisherman. Compared with humans, however, the range of sound frequencies heard by fishes is greatly restricted. Many fishes communicate with each other by producing sounds in their swim bladders, in their throats by rasping their teeth, and in other ways.

 

A fish or other vertebrate seldom has to rely on a single type of sensory information to determine the nature of the environment around it. A catfish uses taste and touch when examining a food object with its oral barbels. Like most other animals, fishes have many touch receptors over their body surface. Pain and temperature receptors also are present in fishes and presumably produce the same kind of information to a fish as to humans. Fishes react in a negative fashion to stimuli that would be painful to human beings, suggesting that they feel a sensation of pain.

 

An important sensory system in fishes that is absent in other vertebrates (except some amphibians) is the lateral line system. This consists of a series of heavily innervated small canals located in the skin and bone around the eyes, along the lower jaw, over the head, and down the mid-side of the body, where it is associated with the scales. Intermittently along these canals are located tiny sensory organs (pit organs) that apparently detect changes in pressure. The system allows a fish to sense changes in water currents and pressure, thereby helping the fish to orient itself to the various changes that occur in the physical environment.

  

i have such a cute ass.. I inherited my father's side of the genes.. little/no ass and small(er) boobs.. my sister got my mom's- nice butt and big boobs.. all the girls in our family have been affected by some sort of endocrine problem, and we've all gained weight from them.. my mom had thyroid, my sister had a pituitary tumor, and mine.. wel.. theres a list... but going from a size 0-3 to a size 13 from your freshman (in high school) year through your sophmore year is a little drastic on a girl.. a lot of it is hipp. though..

Endocrine disrupting chemicals (EDCs) are a serious risk in modern society. These chemical compounds can interfere with the way the body’s hormones work, and they are associated with an array of health issues. Worse, they are almost everywhere: in consumer products such as pesticides, plastics, food storage materials, personal care products, clothing and more, and they also are used in electronics and agriculture.

 

Unfortunately, a number of myths about EDCs being safe have been perpetuated because of a lack of understanding about the realities of these chemicals and their effects on the body.

 

Some people claim EDCs represent no risk at all, and that all of the warnings about them are scare tactics and exaggerated. Others present myths as facts just so product sales will not be hurt. To take or maintain control of your hormone health, you must understand EDC facts so you can make wise decisions regarding your health.

 

Sources

. This EDCs Myth vs. Fact infographic was created by The Hormone Health Network, public education resource of The Endocrine Society.

. Learn about Our Body’s Hormones and Endocrine Disrupting Chemicals.

. Enjoy our health infographics album on Flickr.

 

Endocrine Disruptors

. Endocrine-Disrupting Chemicals: 2nd Endocrine Society Scientific Statement, 2015.

. Endocrine-Disrupting Chemicals: 1st Endocrine Society Scientific Statement, 2009.

. Watch our DES and EDCs research gallery on Flickr.

. Watch our EDCs video playlist on YouTube.

 

Go to the Book with image in the Internet Archive

Title: United States Naval Medical Bulletin Vol. 15, Nos. 1-4, 1921

Creator: U.S. Navy. Bureau of Medicine and Surgery

Publisher:

Sponsor:

Contributor:

Date: 1921

Language: eng

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Table of Contents</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Number 1</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PORTRAIT OF SURGEON GENERAL E. R. STITT, U. S. NAVY —Frontispiece</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREFACE vii</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTICE TO SERVICE CONTRIBUTORS vii</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">THE NAVAL HOSPITAL, MARE ISLAND, CALIF. :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">HISTORY OF THE HOSPITAL.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Captain A. Farenholt, Medical Corps, U. S. N 1</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Operating room technique.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander Lucius W. Johnson, Medical Corps, and Bessie C.

Graham, Nurse Corps, U. S. N 10</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">The urological service.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander A. B. Hepler, Medical Corps, U. S. N__ 16</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">The roentgenological service.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant H. R. Coleman, Medical Corps, U. S. N 30</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">The laboratory.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant G. A. Gray, Medical Corps. U. S. N 34</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Features of organization.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander E. C. White, Medical Corps, U. S. N 40</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">General file and record system.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant D. C. Allen, Medical Corps, U. S. N 4T</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Suggested clinical chart.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander M. C. Baker, Medical Corps, U. S. N 49</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">The theater.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Chief Pharmacist T. C. Hart, Medical Corps, U. S. N 50</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Study of one hundred navy desertions.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant A H. Ehrenclou. Medical Corps, U. S. N., and</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Lieutenant W. H. Wilson, Chaplain Corps, U. S. N. R. F 53</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Surgical failures.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander Lucius W. Johnson, Medical Corps,</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">U. S. N 69</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Circumcision.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander Lucius W. Johnson, Medical Corps, U. S. N 77</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A glue cast for fractures of long bones.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant H. R. Coleman, Medical Corps, U. S. N . 79</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Tuberculin in the early diagnosis of tuberculosis.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant G. A. Gray, Medical Corps, U. S. N 81</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Diphtheria at Mare Island, Calif., in 1920.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant G. A. Gray, Medical Corps, U. S. N 84</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Agglutination of human erythrocytes by sera.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant G. A. Gray, Medical Corps, U. S. N., and Pharmacist's

Mate E. C. Upp, U. S. N 8G</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A method of ringing the hanging drop, etc.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Hospital Apprentice First Class D. G. Willard, U. S. N 92</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Preparation of colloidal gold solution.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Marie Karlen. Reserve Nurse Corps, and Pharmacist's Mate First Class

A. E. Bourke, U. S. N 94</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Report of seventy-five refraction cases.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant W. D. Horner, Medical Corps, U. S. N 95</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Empyema cases.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant E. R. Guinan, Medical Corps, U. S. N 99</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Acute mastoiditis. Page.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant C. N. Meador, Medical Corps, U. S. N 106</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Dental foci in the etiology of systemic disease.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant A. H. Ehrenclou, Medical Corps, and Lieutenant</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">B. F. Loveall, Dental Corps, U. S. N 109</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Transfusion in medical cases.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant D. H. Murray, Medical Corps, TJ. S. N 117</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A DENTAL BRANCH OF THE HOSPITAL COBPS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant B. F. Loveall, Dental Corps, U. S. N 118</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A CASE OF TUBERCULOUS PEBICABDITI8.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant A. H. Ehrenclou, Medical Corps, U. S. N 120</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A CASE OF ACUTE ANILINE POISONING.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant A. H. Ehrenclou, Medical Corps, U. S. N 123</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A CASE OF TUBERCULOUS MENINGITIS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant J. J. Sale, Medical Corps, U. S. N 126</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A CASE OF NEUROPARALYTIC KERATITIS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant C. N. Meador, Medical Corps, U. S. N 127</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Vernal conjunctivitis treated with radium.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant W. D. Horner, Medical Corps, U. S. N 1 128</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A case of acute myelitis.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant L. E. Smith, Medical Corps, U. S. N 130</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A case of osteoma of the tibia.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant F. G. Linde, Medical Corps, U. S. N 131</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A DISLOCATED SEMILUNAR CARTHAGE.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant F. G. Linde, Medical Corps, U. S. N 132</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A CASE OF COMPOUND FRACTURE OF TIBIA AND FIBULA.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant F. G. Linde, Medical Corps, U. S. N 132</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A DEATH FROM NITRIC ACID POISONING.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant G. A. Gray, Medical Corps, U.S. N 133</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NECROSIS OF THE MANDIBLE ; TWO CASES.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant B. F. Loveall, Dental Corps, U. S. N 134</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">HISTORICAL.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Alexis Soyer.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Captain J. S. Taylor, Medical Corps, U. S. N 139</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">EDITORIAL.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Morale 175</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SPECIAL ARTICLES.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Venereal statistics of the Army and Navy: A study of certain published

reports.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Captain C. E. RIggs. Medical Corps, U. S. N 179</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Report of one hundred compound fractures due to shell fragments or

machine-gun bullets.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander A. L. Clifton, Medical Corps, U. S. N__ 191</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A Death From Novarsenobenzol.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander R. A. Torrance, Medical Corps, U. S. N 193</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Mercurochrome —220, in dentistry.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander W. L. Darnall, Dental Corps, U. S. N_ 194</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PROGRESS IN MEDICAL SCIENCES.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">General medicine. —Diagnosis and treatment of pulmonary tuberculosis.

—The clinical recognition of syphilis. —Mercury bichloride Intravenously. —

Transduodenal lavage. — Immunization against diphtheria. —Buccal auscultation

197</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Mental and nervous diseases. — Malingering. —Extending the field of

conscious control. —The patient himself. —Anxiety and fear 210</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Surgery. —Blood transfusion. —Dangers of transfusion. —Mixture of ethyl

chloride, chloroform, and ether for anesthesia. — Skin grafting.—Autoplasties

for baldness. —Bladder tumors 217</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Hygiene and sanitation. —Hospital tires.—Coffee and vitamines 223

Tropical medicine. —Sterilization of ova in bilharziasis.—Antimony in the

treatment of bilharziasis 226</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Eye, ear, nose, and throat. —Cause and diagnosis of glaucoma ; treatment

by myotics.— Corneal disease of tubercular origin. —Action of chloral on the

pupil 227</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTES AND COMMENTS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Enlistments. —Professional training of experienced officers.—The case of

the U. S. S. Pittsburgh. —Prostatic lithiasis.—Cessation of respiration 15

hours before death. —Chloropierin to exterminate rats. —The Annual Report of

the Surgeon General, U. S. Navy. —Finding malarial parasites.— Icterus in

malaria.—Excretion of quinine.— Student health at the University of

Iowa.—Conference on war victims. —Pleasure and profit in the Medical Corps of

the Navy. —Law regarding thermometers. —Adhesive plaster. —The essential in

nursing. —Laxative cookies.—Samoa. —The Navy Mutual Aid Association 236</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">BOOK NOTICES 251</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Number 2</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREFACE<span>   </span>VII</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTICE TO SERVICE CONTRIBUTORS VIII</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SPECIAL ARTICLES:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Treatment of influenza.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander J. L. Neilson, Medical Corps, U. S. N 269</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Intravenous use of magnesium sulphate in influenzal pneumonia.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant J. J. Hogan, Medical Corps, U. S. N. R.F.<span>  </span>277</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Accidental injuries from electric currents.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander W. J. Zalesky and Lieutenant W. T. Brown, Medical Corps,

U. S. N 279</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Methods of sterilization in dentistry.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander H. E. Harvey, Dental Corps, U. S. N. 282</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Peptic ulcer.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant C. S. Norburn, Medical Corps, U. S. N 285</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SURVEY OF FIFTY COURT-MARTIAL PRISONERS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant C. H. Castle, Medical Corps, U. S. N. R.F<span>  </span>291</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Hospital training of apprentices.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant A. H. Ehrenclou, Medical Corps, U. S. N 296</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Methods of instructing hospital corpsmen.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander W. M. Kerr. Medical Corps, U. S.N<span>  </span>302</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Standardizing treatment for venereal disease.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander W. D. Owens, Medical Corps, U. S. N 308</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Plan of organization for a naval hospital.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Captain R. P. Crandall and Commander W. A. Angwin, Medical Corps, U.

S. N 316</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">HISTORICAL:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SURGERY IN THE MIDDLE AGES.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Captain J. S. Taylor, Medical Corps, U. S.N<span>  </span>347</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">EDITORIAL:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Calling a spade an implement of horticultural utility 377</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">"To bide the hobbyhorse with the boys " 378</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SIGGESTED DEVICES:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">RETINOSCOPIC LENS HOLDER.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Captain J. S. Taylor, Medical Corps, U. S. N 383</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Strong room for alcohol and narcotics.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Captain A. Farenholt, Medical Corps, U. S. N 385</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Detection of mosquito larvae.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander J. C. Parham, Medical Corps, U. S. N 380</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">CLINICAL NOTES:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Tuberculous meningitis simulating lethargic encephalitis.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander W. A. Bloedorn, Medical Corps, U. S. N 387</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Advancement of ocular muscles by the Fox technique.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander C. B. Camerer, Medical Corps. U.S. N<span>   </span><span> </span>392</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Surgical treatment of "saddle nose" deformity.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander C. B. Camerer, Medical Corps. U. S. N 397</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A HAND PLASTIC.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander Lucius W. Johnson. Medical Corps, U. S. N 399</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Dislocation of first cervical vertebra.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Captain G. T. Smith, Medical Corps, U. S. N 400</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Death from neo-arsphenamine.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander W. .T. Za leaky and Lieutenant J. B. Bellinger, Medical Corps,

U. S. N 401</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Thrombosis of the lateral sinus.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander E. E. Koebbe, Medical Corps, U. S. N_ 403</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Orchitis complicating tonsillitis.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenants J. D. Benjamin and T. C. Quirk, Medical Corps, U. S. N<span>  </span>408</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Operations for trauma of the urethra.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant W. L. Cowles, Medical Corps, U. S. N. R. P 407</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Sea sickness.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander C. E. Henry. Medical Corps, U. S. N. R. F 410</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Treatment of the " West Indian chancroid."</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander W. H. Michael, Medical Corps, U. S. N 412</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PROGRESS IN MEDICAL SCIENCES:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">General medicine. —The arsphenaniines in therapeutics. —Recital absorption

of glucose 415</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Mental and nervous diseases. —lethargic encephalitis. —Theory of hysteria.

—Mental deficiency 420</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Surgery. —Resuscitation in death under anesthesia. —Advances in anesthesia.

— Sloughing in local anesthesia. —Anesthesia in abdominal surgery. —

Suppurating wounds after abdominal section. —Saving suppurating Incisions.

—Abdominal adhesions. —Perforating gastric and duodenal ulcer. — Persistence of

pyloric and duodenal ulcers. — Diverticula of the duodenum.— Orthopedic

treatment of burns. —Postoperative bronchial irritation. —Care of surgical patients.

—End-to-end anastomosis. —Genital tuberculosis.— Radium therapy of cancer of

bladder. — Radium and malignant genitourinary disease.—Bone tumors. —Fracture

of vertebrae. —Penetrating wounds of chest. —Operation for empyema.—Plastic war

surgery in civil life. —The war's contribution to civil surgery 429</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Hygiene and sanitation. —Typhus fever in Serbia 455</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Pathology, bactkriology, and animal parasitology. —Diagnosis of cholera.

—Staining malarial parasites. —Saprophytysm of venereal organisms. — Variation

in size of red cells. —Anophellnes of California. —Reaction from echinococcus fluid

457</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Eye, ear, nose, and throat.— Encephalitis lethargica<span>  </span>487</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTES AND COMMENTS: <span> </span></p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Bronchospirochaetosis. — Starvation edema. —Dried cabbage as an antiscorbutic.

—Miner's nystagmus. —Endocrines and the teeth. — Orientation of bats. — Sugar

production.- -The teeth of the ancient Egyptians. —Treatment of enlarged

thymus. —Plague in Paris.— Antivenereal campaign in Rouen.— Medical school of

the University of Virginia. —Postgraduate study In the Japanese Navy. — National

Academy of Science.—Peking Unjon Medical College. — The dye Industry. — Naval

medical service as a career. —Naval dispensary and hospital defined.— Death of

Anton Weichselbaum. — Action of the Women's Civic League, Maiden, Mass. — Dr.

Russel H. Boggs. — Preservation of leather. —Service publications. —Picric acid

<span> </span>469</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">REPORTS :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Sewage system in Charlotte Amalia.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant R. L. Pettigrew, Civil Engineer Corps, U. S. N. and

Lieutenant E. Peterson. Medical Corps, U. S. N 481</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Application of the Schick reaction to 2,011 naval recruits.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant B. F. Norwood. Medical Corps, U. S. N 486</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Smallpox in Haiti.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander K. C. Melborn, Medical Corps, U. S. N 492</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Sanitary report on Libau, Latvia.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander A. C. Smith and Lieutenant R. P. Parsons,

Medical Corps, U. S. N 492</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Summer school, Hampton Roads, Va.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander K. E. Lowman, Medical Corps, U. S. N 495</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">INFORMATION WANTED 498</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">BOOK NOTICES 499</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Number 3</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTICE TO SERVICE CONTRIBUTORS VI</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">CLINICAL NOTES : Surgical service of the United States Naval Hospital,

New Orleans, La.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander W. J. Riddick and Lieutenant Commander E. A.

Stephens, Medical Corps, U. S.N.<span>    </span><span> </span>507</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A CASE OF HYSTERIA IN THE NAVAL SERVICE.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander W. A. Bloedorn, Medical Corps, U. S. N.<span>   </span>515</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A CASE OF HYSTERICAL CONTRACTURE.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant A. H. Ehrenclou, Medical Corps, U. S. N 521</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">X-RAY PROCEDURE AND TECHNIQUE.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander I. E. Jacobs, Medical Corps, and Chief

Pharmacist's Mate C. B. Worster, U. S. N 524</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Interpretation of abdominal rigidity.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander Lucius W. Johnson, Medical Corps, U. S. N<span>    </span><span> </span>529</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A CASE OF ECHINOCOCCUS CYST.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant C. S. Norburn, Medical Corps, U. S. N 530</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NONCORRODIBLE INSTRUMENTS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander G. C. Thomas, Medical Corps, U. S. N 532</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Aseptic technique for canal instruments.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander H. E. Harvey, Dental Corps, U. S. N 533</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Traumata due to falling.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander H. H. Lane, Medical Corps, U. S. N<span>  </span><span> </span>535</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Administration of neosalvarsan.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant J. B. Bostick, Medical Corps, U. S. N 536</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Diet deficiency in Vincent's angina.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant C. H. Morris, Dental Corps, U. S. N 540</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Vincent's infection of the -mouth.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant (j. g.) J. B. Goodall, Dental Corps, U. S. N. R. F <span> </span>542</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Penetrating wound of the pelvis.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant F. P. Gardner, Medical Corps, U. S. N 544</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Traumatic rupture of spleen —removal.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander F. H. Bowman, Medical Corps, U.S. N., and

Lieutenant Commander E. M. Foote, Medical Corps, U. S. N. R. F 545</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Operation for wrist drop.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant J. I. Yohannan, Medical Corps, U. S. N 547</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A PLASTIC OPERATION ON THE MUSCLES OF THE SHOULDER.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant R. W. Auerbach, Medical Corps, U. S. N 54S</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A SIMPLE OPERATION FOR TRICHIASIS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant H. S. Cragin, Medical Corps, U. S. N. R. F 551</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A CASE OF ADENO-CARCINOMA.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander M. Boland, Medical Corps, U. S. N— 552</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Chancroidal infections.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant W. F. Pearce, Medical Corps, U. S. N 554</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A CA8E OF INNOCENT SYPHILIS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant J. W. Jones, Medical Corps, U. S. N 556</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A CASE OF CARCINOMA OF THE TESTICLE.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant W. J. Corcoran, Medical Corps, U. S. N 557</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Removal of an unusually large tumor.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander E. L. Jones, Medical Corps, U. S. N 558</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">HISTORICAL:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A RETROSPECT OF NAVAL AND MILITARY MEDICINE.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Captain J. S. Taylor, Medical Corps, U. S. N 561</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">EDITORIAL :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Accidental poisoning — Contributing to the Bulletin —The omission of

the—The future of nursing — Comparative values 627</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PROGRESS IN MEDICAL SCIENCES :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">General medicine — Mechanism of hiccough — Gases In arterial blood—Treatment

of arsenic poisoning —Treatment of encephalitis letharglca —New test for

nephritis—Blood in pellagra and beri beri —Ocular symptoms in sinus

disease—Reaction from repeated transfusions —Eye symptoms in epidemic

encephalitis —Diagnosis and treatment of hemorrhoids —Cost of venereal

disease—Future of medicine in the United States 637</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Mental and nervous diseases —The criminal—Brain lesions of dementia

praecox —Follow-up studies on mental patients 652</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Surgery—Trauma of the abdomen— Rubber dam tampon —Diagnosis of gastric

or duodenal ulcers —Postoperative thrombophlebitis — Treatment of fractured

patella —Affections of the tibial tubercle— 655</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Hygiene and Sanitation —Sanitary features of merchant ships 659</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTES AND COMMENTS :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Errata —Centenary of von Helmholtz —Retirement of Filippo Rho, Surgeon

General, Italian Navy—A diagnostic point in tuberculosis —Curing hemorrhoids

—The X-ray and art— Industrial code of<span>  </span>New

York —Preservation of eyesight —Basal metabolism —American Society of Tropical

Medicine —Laboratory work in the Far East— Dentistry in South America

—Fireprooflng of fabrics—The exploration of Mount Everest — Physical

development in Japan — Hiccough and encephalitis lethargica —Use of fish as

food in France — Service items 665</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">REPORTS :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Rat-Proofing at the United States Navy Yard, Key West, Fla.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander P. E. Garrison, Medical Corps, U. S. N 673</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Report of the Fifth Congress of the International Society of Surgery,

Paris.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant S. B. Burk, Medical Corps, U. S. N. R. F. (Inactive) 681</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Smallpox in Port Au Prince, Haiti.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant C. J. Brown, Medical Corps, U. S. N 695</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Medical Department of the United States Naval Torpedo Station,

Alexandria, Va.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander C. C. Kress, Medical Corps, U. S. N 701</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">The Herman-Perutz Reaction.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant G. V. Genzmer, Medical Corps, U. S. N. R. F 708</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">BOOK NOTICES 711</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Number 4</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREFACE V</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTICE TO SERVICE CONTRIBUTORS VI</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SPECIAL ARTICLES :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Color blindness.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Captain E. J. Grow, Medical Corps, U. S. N 717</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Cardiac irregularity.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander E. U. Reed, Medical Corps, U. S. N 732</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Handling of recruits, Marine Barracks, Parris Island.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander J. C. Parham, Medical Corps, U. S. N 740</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Four centuries in the treatment of syphilis.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant L. W. Shaffer, Medical Corps, U. S. N 749</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A Marine Corps field hospital.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander G. F. Cottle, Medical Corps, U. S. N<span>  </span><span> </span>762</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Training and care of the football squad, U. S. Naval Academy, Annapolis,

Md.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant M. H. Roberts, Medical Corps, U. S. N. R. F 770</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Gas poisoning in warfare.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant G. H. Mankin, Medical Corps, U. S. N 775</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Venereal prophylaxis among U. S. Marines at Honolulu.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander H. H. Lane, Medical Corps, U. S. N_. 783</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">HISTORICAL :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">The Manila Galleon.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander W. M. Kerr, Medical Corps, U. S. N. 787</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">EDITORIAL :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">On learning to write-—On several phases of syphilis 801</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SUGGESTED DEVICES :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Dental X-ray film holder.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander H. E. Harvey, Dental Corps. U. S. N_- 807</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Suggestion for recording dental conditions.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander H. E. Harvey, Dental Corps, U. S. N-- 807</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">CLINICAL NOTES :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A CASE OF CUTANEOUS SPOROTRICHOSIS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander R. E. Hoyt, Medical Corps, U. S. N 809</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Report of pellagra in Haiti.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander G. F. Clark, Medical Corps, U. S. N__ 813</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Acute rheumatic fever.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant W. M. Alberty, Medical Corps, U. S. N 814</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A case of poisoning by oil of chenopodium.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant B. F. Norwood, Medical Corps, U. S. N 818</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Brushing the teeth.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander H. E. Harvey, Dental Corps, U. S. N<span>  </span><span> </span>824</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">TWENTY-EIGHT CASES OF PNEUMONIA.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant J. R. Jeffrey, Medical Corps, U. S. N 825</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A CASE OF TUBERCULOUS MENINGITIS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander S. P. Taylor, Medical Corps, U. S. N— 830</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Cholecystectomy <span> </span>and pyelotomy in

Guam.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander A. H. Robnett, Medical Corps, U. S. N 831</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Elephantiasis of the scrotum.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant L. W. Breene, Medical Corps, U. S. N., and W. Zur Linden,

chief pharmacist, Medical Corps, U. S. N 884</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Rules for massage.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander W. S. Bainbridge, Medical Corps, U. S. N. R. F— 835</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PROGRESS IN MEDICAL SCIENCES :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">General medicine. —Transfusion of blood—Diabetes mellitus In the Negro

race— Diagnosis of syphilis In malarial subjects —So-called diseases of the

blood— Singultus— The role of the prostate and</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">seminal vesicles in arthritis —Medical aspects of naval aviation — Treating

syphilitics—The etiology of scurvy —Food accessory factors in relation to the

teeth 839</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Surgery. —Immediate surgery in fighting ships —Immediate surgery of war

wounds as practiced in hospital ships —The surgical treatment of empyema by a

closed method—Willems treatment of</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">knee-joint injuries —Observations on primary venereal sores—Resection

of the small intestine for war wounds —Tetanus in the British Army during the

European War 855</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Tropical medicine. —New method of treatment of trypanosomiasis — Differential

diagnosis in tropical fevers —Schistosomiasis in the Yangtse Valley—Carriers of

dysenteriae among soldiers —Liverpool School of Tropical Medicine 870</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Pathology, bacteriology, and animal parasitology. — Cultivation of gonococcus—Aestivo-autumnal

malaria Plasmodia —Virulence of diphtheria-like organisms 885</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Chemistry and pharmacy.—Absorption of calcium salts in man— Improvements

in the Nephelometer-Colorimeter — Substitution of turbidimetry for nephelometry

in certain biochemical methods of analysis— Creatinuria —Phosphoric acid in the

blood of normal infants—Basal metabolism of normal women—Fat-soluble vitamine— Standards

for normal basal metabolism 887</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Eye, ear, nose, and throat.- —Injuries to the ear in modern warfare— Injuries

to the ear in modern warfare— Symptomatology and diagnosis of foreign bodies in

the air and food passages—Etiology and prevention of injuries to the eye

—Mosher-Totl operation on the lachrymal sac —-Tuberculosis of the middle ear

892</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTES AND COMMENTS :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Colles's Fracture—The French view of an American medical congress —Case

Records of the Massachusetts General Hospital— National cancer week- —

Pharmacopoeia of China —Municipal disposal of garbage—American Journal of

Tropical Medicine —Danger of week-end camping in the Tropics — Influenza

epidemic in the British Navy —Benvenuto Cellini—A Consulting Surgeon in the

Near</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">East—Asphyxiation in Garages —Dental service In the British Navy

—Surgeon Captain Lomas, R. N.—Counsels and Ideals from the Writings of William

Osler —John Keats, apothecary and poet — Life and times of Ambroise

Pare—Treatment of ozena —Lead poisoning in the pottery trade—The International

Journal of Gastro-Enterology— Treatment of malarial fever —Formaldehyde

poisoning — Toxic effects of shaking arsphenamine solution —Peking Union Medical

College —Milk standards 901</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">BOOK NOTICES 921</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">INDEX 983</p>

 

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Note: The colors, contrast and appearance of these illustrations are unlikely to be true to life. They are derived from scanned images that have been enhanced for machine interpretation and have been altered from their originals.

 

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Image source: Pesticide Action Network Europe twitter feed.

All our posts about EDCs, pesticides, pregnancy. More cartoons.

 

This European Starling sat on this fence post long enough for me to take a handful of shots. Usually, I find they fly off straight away, so I was lucky this time. These birds need to be seen close in order to see the patterns and iridescent colours of their beautiful feathers. Taken on 14 April 2014, when I spent the day driving the backroads SE of Calgary with my daughter.

 

"First brought to North America by Shakespeare enthusiasts in the nineteenth century, European Starlings are now among the continent’s most numerous songbirds. They are stocky black birds with short tails, triangular wings, and long, pointed bills. Though they’re sometimes resented for their abundance and aggressiveness, they’re still dazzling birds when you get a good look. Covered in white spots during winter, they turn dark and glossy in summer. For much of the year, they wheel through the sky and mob lawns in big, noisy flocks." From allaboutbirds.

 

www.allaboutbirds.org/guide/european_starling/id

 

en.wikipedia.org/wiki/Common_Starling

 

"The success of the European Starling in North America is nothing less than phenomenal. Although estimates vary, it is commonly believed that a total of about 100 individuals was released into Central Park, in New York City, in 1890 and 1891. The entire North American population, now numbering more than 200 million and distributed across most of the continent, is derived from these few birds. This is arguably the most successful avian introduction to this continent. Although the European Starling is most frequently associated with disturbed areas created by man, it has had a significant impact on our native avifauna. In particular, it offers intense competition for nesting cavities and has had a detrimental effect on many native cavity-nesting species. Because of the starling’s abundance and association with humans, many aspects of its natural history are known in detail, from studies both in its native range and in areas to which it was introduced. It has also served as a model for studying basic avian biology. Recent research has done much to illuminate the mechanics of flight and control of the endocrine system (e.g. see Nicholls et al. 1988; Dial." From birdsofalberta.

 

birdsofalberta.com/List/detail.php?id=307et al. 1991)

  

Navajo Technical University (NTU) was awarded $220,000 for 24 months, in 2018, under the U.S. Department of Agriculture (USDA) National Institute of Food and Agriculture (NIFA) Tribal College Research Grant Program, for the Fabrication and Education of Multi-Purpose Nano Electrochemical Sensor to Detect Endocrine Disruptors (Bisphenol Compounds) and Glucose in Navajo Nation project, that is led by NTU Chemistry Associate Professor Dr. Thiagarajan Soundappan, in Crownpoint, NM, on Sept. 9, 2019. Bisphenol also known as BPA can be found items such as receipts from thermal printers, and certain plastic bottles and containers. The research funding provides equipment and staff for the Electrochemical Research wet-laboratory in this one-year old facility.

  

Robinson Tom (Navajo) (SEEN) and Michael Nelwood are making BPA bio sensors that detect both BPA and glucose without the use of a needle or blood sample. The higher number of diabetes and high use of plastic containers in the Navajo Nation is a clear need for this type of sensor. The lack of nutritional and varied food sources on the reservation (food desert) lowers the community’s immune defense, making them vulnerable to diseases caused attributed to BPA contact and high glucose.

  

Tom also has experience with radon detection research for USDA, and DoD research developing more efficient battlefield batteries for U.S. servicemen. On a personal side, he has family members who are dealing with diabetes, so his motivation to develop the BPA/glucose sensors are close to him. Nellwood will take over research operations when Tom graduates next semester. Not only will the research be turned over, the will carry on with the in-demand community awareness sessions that teach the tribal community about the health concerns.

 

Both are U.S. Army veterans.

  

NTU was initially established in 1979 as the Navajo Skill Center and is the Navajo Nation’s first university. A highly respected land-grant institution, NTU offers technical, vocational, and academic degrees, as well as community education, in a student-oriented, hands-on learning environment with state-of-the-art classroom equipment.

  

In 1994, 29 tribal colleges received land-grant university (LGU) status, giving them access to federal government resources that would improve the lives of Native students through higher education and help propel American Indians toward self-sufficiency. These resources also support innovative research, education, and extension programs that positively impact agriculture and food production. The 1994 Land-Grants often serve as the primary institution of scientific inquiry, knowledge and learning for reservation communities.

 

USDA Photo by Lance Cheung, with permission from NTU.

  

For more information, please see:

 

nifa.usda.gov/program/tribal-college-research-grant-program

 

nifa.usda.gov/resource/first-20-years-1994-land-grant-institutions

Fish, any of approximately 34,000 species of vertebrate animals (phylum Chordata) found in the fresh and salt waters of the world. Living species range from the primitive jawless lampreys and hagfishes through the cartilaginous sharks, skates, and rays to the abundant and diverse bony fishes. Most fish species are cold-blooded; however, one species, the opah (Lampris guttatus), is warm-blooded.

 

The term fish is applied to a variety of vertebrates of several evolutionary lines. It describes a life-form rather than a taxonomic group. As members of the phylum Chordata, fish share certain features with other vertebrates. These features are gill slits at some point in the life cycle, a notochord, or skeletal supporting rod, a dorsal hollow nerve cord, and a tail. Living fishes represent some five classes, which are as distinct from one another as are the four classes of familiar air-breathing animals—amphibians, reptiles, birds, and mammals. For example, the jawless fishes (Agnatha) have gills in pouches and lack limb girdles. Extant agnathans are the lampreys and the hagfishes. As the name implies, the skeletons of fishes of the class Chondrichthyes (from chondr, “cartilage,” and ichthyes, “fish”) are made entirely of cartilage. Modern fish of this class lack a swim bladder, and their scales and teeth are made up of the same placoid material. Sharks, skates, and rays are examples of cartilaginous fishes. The bony fishes are by far the largest class. Examples range from the tiny seahorse to the 450-kg (1,000-pound) blue marlin, from the flattened soles and flounders to the boxy puffers and ocean sunfishes. Unlike the scales of the cartilaginous fishes, those of bony fishes, when present, grow throughout life and are made up of thin overlapping plates of bone. Bony fishes also have an operculum that covers the gill slits.

 

The study of fishes, the science of ichthyology, is of broad importance. Fishes are of interest to humans for many reasons, the most important being their relationship with and dependence on the environment. A more obvious reason for interest in fishes is their role as a moderate but important part of the world’s food supply. This resource, once thought unlimited, is now realized to be finite and in delicate balance with the biological, chemical, and physical factors of the aquatic environment. Overfishing, pollution, and alteration of the environment are the chief enemies of proper fisheries management, both in fresh waters and in the ocean. (For a detailed discussion of the technology and economics of fisheries, see commercial fishing.) Another practical reason for studying fishes is their use in disease control. As predators on mosquito larvae, they help curb malaria and other mosquito-borne diseases.

 

Fishes are valuable laboratory animals in many aspects of medical and biological research. For example, the readiness of many fishes to acclimate to captivity has allowed biologists to study behaviour, physiology, and even ecology under relatively natural conditions. Fishes have been especially important in the study of animal behaviour, where research on fishes has provided a broad base for the understanding of the more flexible behaviour of the higher vertebrates. The zebra fish is used as a model in studies of gene expression.

 

There are aesthetic and recreational reasons for an interest in fishes. Millions of people keep live fishes in home aquariums for the simple pleasure of observing the beauty and behaviour of animals otherwise unfamiliar to them. Aquarium fishes provide a personal challenge to many aquarists, allowing them to test their ability to keep a small section of the natural environment in their homes. Sportfishing is another way of enjoying the natural environment, also indulged in by millions of people every year. Interest in aquarium fishes and sportfishing supports multimillion-dollar industries throughout the world.

 

Fishes have been in existence for more than 450 million years, during which time they have evolved repeatedly to fit into almost every conceivable type of aquatic habitat. In a sense, land vertebrates are simply highly modified fishes: when fishes colonized the land habitat, they became tetrapod (four-legged) land vertebrates. The popular conception of a fish as a slippery, streamlined aquatic animal that possesses fins and breathes by gills applies to many fishes, but far more fishes deviate from that conception than conform to it. For example, the body is elongate in many forms and greatly shortened in others; the body is flattened in some (principally in bottom-dwelling fishes) and laterally compressed in many others; the fins may be elaborately extended, forming intricate shapes, or they may be reduced or even lost; and the positions of the mouth, eyes, nostrils, and gill openings vary widely. Air breathers have appeared in several evolutionary lines.

 

Many fishes are cryptically coloured and shaped, closely matching their respective environments; others are among the most brilliantly coloured of all organisms, with a wide range of hues, often of striking intensity, on a single individual. The brilliance of pigments may be enhanced by the surface structure of the fish, so that it almost seems to glow. A number of unrelated fishes have actual light-producing organs. Many fishes are able to alter their coloration—some for the purpose of camouflage, others for the enhancement of behavioral signals.

 

Fishes range in adult length from less than 10 mm (0.4 inch) to more than 20 metres (60 feet) and in weight from about 1.5 grams (less than 0.06 ounce) to many thousands of kilograms. Some live in shallow thermal springs at temperatures slightly above 42 °C (100 °F), others in cold Arctic seas a few degrees below 0 °C (32 °F) or in cold deep waters more than 4,000 metres (13,100 feet) beneath the ocean surface. The structural and, especially, the physiological adaptations for life at such extremes are relatively poorly known and provide the scientifically curious with great incentive for study.

 

Almost all natural bodies of water bear fish life, the exceptions being very hot thermal ponds and extremely salt-alkaline lakes, such as the Dead Sea in Asia and the Great Salt Lake in North America. The present distribution of fishes is a result of the geological history and development of Earth as well as the ability of fishes to undergo evolutionary change and to adapt to the available habitats. Fishes may be seen to be distributed according to habitat and according to geographical area. Major habitat differences are marine and freshwater. For the most part, the fishes in a marine habitat differ from those in a freshwater habitat, even in adjacent areas, but some, such as the salmon, migrate from one to the other. The freshwater habitats may be seen to be of many kinds. Fishes found in mountain torrents, Arctic lakes, tropical lakes, temperate streams, and tropical rivers will all differ from each other, both in obvious gross structure and in physiological attributes. Even in closely adjacent habitats where, for example, a tropical mountain torrent enters a lowland stream, the fish fauna will differ. The marine habitats can be divided into deep ocean floors (benthic), mid-water oceanic (bathypelagic), surface oceanic (pelagic), rocky coast, sandy coast, muddy shores, bays, estuaries, and others. Also, for example, rocky coastal shores in tropical and temperate regions will have different fish faunas, even when such habitats occur along the same coastline.

 

Although much is known about the present geographical distribution of fishes, far less is known about how that distribution came about. Many parts of the fish fauna of the fresh waters of North America and Eurasia are related and undoubtedly have a common origin. The faunas of Africa and South America are related, extremely old, and probably an expression of the drifting apart of the two continents. The fauna of southern Asia is related to that of Central Asia, and some of it appears to have entered Africa. The extremely large shore-fish faunas of the Indian and tropical Pacific oceans comprise a related complex, but the tropical shore fauna of the Atlantic, although containing Indo-Pacific components, is relatively limited and probably younger. The Arctic and Antarctic marine faunas are quite different from each other. The shore fauna of the North Pacific is quite distinct, and that of the North Atlantic more limited and probably younger. Pelagic oceanic fishes, especially those in deep waters, are similar the world over, showing little geographical isolation in terms of family groups. The deep oceanic habitat is very much the same throughout the world, but species differences do exist, showing geographical areas determined by oceanic currents and water masses.

 

All aspects of the life of a fish are closely correlated with adaptation to the total environment, physical, chemical, and biological. In studies, all the interdependent aspects of fish, such as behaviour, locomotion, reproduction, and physical and physiological characteristics, must be taken into account.

 

Correlated with their adaptation to an extremely wide variety of habitats is the extremely wide variety of life cycles that fishes display. The great majority hatch from relatively small eggs a few days to several weeks or more after the eggs are scattered in the water. Newly hatched young are still partially undeveloped and are called larvae until body structures such as fins, skeleton, and some organs are fully formed. Larval life is often very short, usually less than a few weeks, but it can be very long, some lampreys continuing as larvae for at least five years. Young and larval fishes, before reaching sexual maturity, must grow considerably, and their small size and other factors often dictate that they live in a habitat different than that of the adults. For example, most tropical marine shore fishes have pelagic larvae. Larval food also is different, and larval fishes often live in shallow waters, where they may be less exposed to predators.

 

After a fish reaches adult size, the length of its life is subject to many factors, such as innate rates of aging, predation pressure, and the nature of the local climate. The longevity of a species in the protected environment of an aquarium may have nothing to do with how long members of that species live in the wild. Many small fishes live only one to three years at the most. In some species, however, individuals may live as long as 10 or 20 or even 100 years.

 

Fish behaviour is a complicated and varied subject. As in almost all animals with a central nervous system, the nature of a response of an individual fish to stimuli from its environment depends upon the inherited characteristics of its nervous system, on what it has learned from past experience, and on the nature of the stimuli. Compared with the variety of human responses, however, that of a fish is stereotyped, not subject to much modification by “thought” or learning, and investigators must guard against anthropomorphic interpretations of fish behaviour.

 

Fishes perceive the world around them by the usual senses of sight, smell, hearing, touch, and taste and by special lateral line water-current detectors. In the few fishes that generate electric fields, a process that might best be called electrolocation aids in perception. One or another of these senses often is emphasized at the expense of others, depending upon the fish’s other adaptations. In fishes with large eyes, the sense of smell may be reduced; others, with small eyes, hunt and feed primarily by smell (such as some eels).

 

Specialized behaviour is primarily concerned with the three most important activities in the fish’s life: feeding, reproduction, and escape from enemies. Schooling behaviour of sardines on the high seas, for instance, is largely a protective device to avoid enemies, but it is also associated with and modified by their breeding and feeding requirements. Predatory fishes are often solitary, lying in wait to dart suddenly after their prey, a kind of locomotion impossible for beaked parrot fishes, which feed on coral, swimming in small groups from one coral head to the next. In addition, some predatory fishes that inhabit pelagic environments, such as tunas, often school.

 

Sleep in fishes, all of which lack true eyelids, consists of a seemingly listless state in which the fish maintains its balance but moves slowly. If attacked or disturbed, most can dart away. A few kinds of fishes lie on the bottom to sleep. Most catfishes, some loaches, and some eels and electric fishes are strictly nocturnal, being active and hunting for food during the night and retiring during the day to holes, thick vegetation, or other protective parts of the environment.

 

Communication between members of a species or between members of two or more species often is extremely important, especially in breeding behaviour (see below Reproduction). The mode of communication may be visual, as between the small so-called cleaner fish and a large fish of a very different species. The larger fish often allows the cleaner to enter its mouth to remove gill parasites. The cleaner is recognized by its distinctive colour and actions and therefore is not eaten, even if the larger fish is normally a predator. Communication is often chemical, signals being sent by specific chemicals called pheromones.

 

Many fishes have a streamlined body and swim freely in open water. Fish locomotion is closely correlated with habitat and ecological niche (the general position of the animal to its environment).

 

Many fishes in both marine and fresh waters swim at the surface and have mouths adapted to feed best (and sometimes only) at the surface. Often such fishes are long and slender, able to dart at surface insects or at other surface fishes and in turn to dart away from predators; needlefishes, halfbeaks, and topminnows (such as killifish and mosquito fish) are good examples. Oceanic flying fishes escape their predators by gathering speed above the water surface, with the lower lobe of the tail providing thrust in the water. They then glide hundreds of yards on enlarged, winglike pectoral and pelvic fins. South American freshwater flying fishes escape their enemies by jumping and propelling their strongly keeled bodies out of the water.

 

So-called mid-water swimmers, the most common type of fish, are of many kinds and live in many habitats. The powerful fusiform tunas and the trouts, for example, are adapted for strong, fast swimming, the tunas to capture prey speedily in the open ocean and the trouts to cope with the swift currents of streams and rivers. The trout body form is well adapted to many habitats. Fishes that live in relatively quiet waters such as bays or lake shores or slow rivers usually are not strong, fast swimmers but are capable of short, quick bursts of speed to escape a predator. Many of these fishes have their sides flattened, examples being the sunfish and the freshwater angelfish of aquarists. Fish associated with the bottom or substrate usually are slow swimmers. Open-water plankton-feeding fishes almost always remain fusiform and are capable of rapid, strong movement (for example, sardines and herrings of the open ocean and also many small minnows of streams and lakes).

 

Bottom-living fishes are of many kinds and have undergone many types of modification of their body shape and swimming habits. Rays, which evolved from strong-swimming mid-water sharks, usually stay close to the bottom and move by undulating their large pectoral fins. Flounders live in a similar habitat and move over the bottom by undulating the entire body. Many bottom fishes dart from place to place, resting on the bottom between movements, a motion common in gobies. One goby relative, the mudskipper, has taken to living at the edge of pools along the shore of muddy mangrove swamps. It escapes its enemies by flipping rapidly over the mud, out of the water. Some catfishes, synbranchid eels, the so-called climbing perch, and a few other fishes venture out over damp ground to find more promising waters than those that they left. They move by wriggling their bodies, sometimes using strong pectoral fins; most have accessory air-breathing organs. Many bottom-dwelling fishes live in mud holes or rocky crevices. Marine eels and gobies commonly are found in such habitats and for the most part venture far beyond their cavelike homes. Some bottom dwellers, such as the clingfishes (Gobiesocidae), have developed powerful adhesive disks that enable them to remain in place on the substrate in areas such as rocky coasts, where the action of the waves is great.

 

The methods of reproduction in fishes are varied, but most fishes lay a large number of small eggs, fertilized and scattered outside of the body. The eggs of pelagic fishes usually remain suspended in the open water. Many shore and freshwater fishes lay eggs on the bottom or among plants. Some have adhesive eggs. The mortality of the young and especially of the eggs is very high, and often only a few individuals grow to maturity out of hundreds, thousands, and in some cases millions of eggs laid.

 

Males produce sperm, usually as a milky white substance called milt, in two (sometimes one) testes within the body cavity. In bony fishes a sperm duct leads from each testis to a urogenital opening behind the vent or anus. In sharks and rays and in cyclostomes the duct leads to a cloaca. Sometimes the pelvic fins are modified to help transmit the milt to the eggs at the female’s vent or on the substrate where the female has placed them. Sometimes accessory organs are used to fertilize females internally—for example, the claspers of many sharks and rays.

 

In the females the eggs are formed in two ovaries (sometimes only one) and pass through the ovaries to the urogenital opening and to the outside. In some fishes the eggs are fertilized internally but are shed before development takes place. Members of about a dozen families each of bony fishes (teleosts) and sharks bear live young. Many skates and rays also bear live young. In some bony fishes the eggs simply develop within the female, the young emerging when the eggs hatch (ovoviviparous). Others develop within the ovary and are nourished by ovarian tissues after hatching (viviparous). There are also other methods utilized by fishes to nourish young within the female. In all live-bearers the young are born at a relatively large size and are few in number. In one family of primarily marine fishes, the surfperches from the Pacific coast of North America, Japan, and Korea, the males of at least one species are born sexually mature, although they are not fully grown.

 

Some fishes are hermaphroditic—an individual producing both sperm and eggs, usually at different stages of its life. Self-fertilization, however, is probably rare.

 

Successful reproduction and, in many cases, defense of the eggs and the young are assured by rather stereotypical but often elaborate courtship and parental behaviour, either by the male or the female or both. Some fishes prepare nests by hollowing out depressions in the sand bottom (cichlids, for example), build nests with plant materials and sticky threads excreted by the kidneys (sticklebacks), or blow a cluster of mucus-covered bubbles at the water surface (gouramis). The eggs are laid in these structures. Some varieties of cichlids and catfishes incubate eggs in their mouths.

 

Some fishes, such as salmon, undergo long migrations from the ocean and up large rivers to spawn in the gravel beds where they themselves hatched (anadromous fishes). Some, such as the freshwater eels (family Anguillidae), live and grow to maturity in fresh water and migrate to the sea to spawn (catadromous fishes). Other fishes undertake shorter migrations from lakes into streams, within the ocean, or enter spawning habitats that they do not ordinarily occupy in other ways.

 

The basic structure and function of the fish body are similar to those of all other vertebrates. The usual four types of tissues are present: surface or epithelial, connective (bone, cartilage, and fibrous tissues, as well as their derivative, blood), nerve, and muscle tissues. In addition, the fish’s organs and organ systems parallel those of other vertebrates.

 

The typical fish body is streamlined and spindle-shaped, with an anterior head, a gill apparatus, and a heart, the latter lying in the midline just below the gill chamber. The body cavity, containing the vital organs, is situated behind the head in the lower anterior part of the body. The anus usually marks the posterior termination of the body cavity and most often occurs just in front of the base of the anal fin. The spinal cord and vertebral column continue from the posterior part of the head to the base of the tail fin, passing dorsal to the body cavity and through the caudal (tail) region behind the body cavity. Most of the body is of muscular tissue, a high proportion of which is necessitated by swimming. In the course of evolution this basic body plan has been modified repeatedly into the many varieties of fish shapes that exist today.

 

The skeleton forms an integral part of the fish’s locomotion system, as well as serving to protect vital parts. The internal skeleton consists of the skull bones (except for the roofing bones of the head, which are really part of the external skeleton), the vertebral column, and the fin supports (fin rays). The fin supports are derived from the external skeleton but will be treated here because of their close functional relationship to the internal skeleton. The internal skeleton of cyclostomes, sharks, and rays is of cartilage; that of many fossil groups and some primitive living fishes is mostly of cartilage but may include some bone. In place of the vertebral column, the earliest vertebrates had a fully developed notochord, a flexible stiff rod of viscous cells surrounded by a strong fibrous sheath. During the evolution of modern fishes the rod was replaced in part by cartilage and then by ossified cartilage. Sharks and rays retain a cartilaginous vertebral column; bony fishes have spool-shaped vertebrae that in the more primitive living forms only partially replace the notochord. The skull, including the gill arches and jaws of bony fishes, is fully, or at least partially, ossified. That of sharks and rays remains cartilaginous, at times partially replaced by calcium deposits but never by true bone.

 

The supportive elements of the fins (basal or radial bones or both) have changed greatly during fish evolution. Some of these changes are described in the section below (Evolution and paleontology). Most fishes possess a single dorsal fin on the midline of the back. Many have two and a few have three dorsal fins. The other fins are the single tail and anal fins and paired pelvic and pectoral fins. A small fin, the adipose fin, with hairlike fin rays, occurs in many of the relatively primitive teleosts (such as trout) on the back near the base of the caudal fin.

 

The skin of a fish must serve many functions. It aids in maintaining the osmotic balance, provides physical protection for the body, is the site of coloration, contains sensory receptors, and, in some fishes, functions in respiration. Mucous glands, which aid in maintaining the water balance and offer protection from bacteria, are extremely numerous in fish skin, especially in cyclostomes and teleosts. Since mucous glands are present in the modern lampreys, it is reasonable to assume that they were present in primitive fishes, such as the ancient Silurian and Devonian agnathans. Protection from abrasion and predation is another function of the fish skin, and dermal (skin) bone arose early in fish evolution in response to this need. It is thought that bone first evolved in skin and only later invaded the cartilaginous areas of the fish’s body, to provide additional support and protection. There is some argument as to which came first, cartilage or bone, and fossil evidence does not settle the question. In any event, dermal bone has played an important part in fish evolution and has different characteristics in different groups of fishes. Several groups are characterized at least in part by the kind of bony scales they possess.

 

Scales have played an important part in the evolution of fishes. Primitive fishes usually had thick bony plates or thick scales in several layers of bone, enamel, and related substances. Modern teleost fishes have scales of bone, which, while still protective, allow much more freedom of motion in the body. A few modern teleosts (some catfishes, sticklebacks, and others) have secondarily acquired bony plates in the skin. Modern and early sharks possessed placoid scales, a relatively primitive type of scale with a toothlike structure, consisting of an outside layer of enamel-like substance (vitrodentine), an inner layer of dentine, and a pulp cavity containing nerves and blood vessels. Primitive bony fishes had thick scales of either the ganoid or the cosmoid type. Cosmoid scales have a hard, enamel-like outer layer, an inner layer of cosmine (a form of dentine), and then a layer of vascular bone (isopedine). In ganoid scales the hard outer layer is different chemically and is called ganoin. Under this is a cosminelike layer and then a vascular bony layer. The thin, translucent bony scales of modern fishes, called cycloid and ctenoid (the latter distinguished by serrations at the edges), lack enameloid and dentine layers.

 

Skin has several other functions in fishes. It is well supplied with nerve endings and presumably receives tactile, thermal, and pain stimuli. Skin is also well supplied with blood vessels. Some fishes breathe in part through the skin, by the exchange of oxygen and carbon dioxide between the surrounding water and numerous small blood vessels near the skin surface.

 

Skin serves as protection through the control of coloration. Fishes exhibit an almost limitless range of colours. The colours often blend closely with the surroundings, effectively hiding the animal. Many fishes use bright colours for territorial advertisement or as recognition marks for other members of their own species, or sometimes for members of other species. Many fishes can change their colour to a greater or lesser degree, by movement of pigment within the pigment cells (chromatophores). Black pigment cells (melanophores), of almost universal occurrence in fishes, are often juxtaposed with other pigment cells. When placed beneath iridocytes or leucophores (bearing the silvery or white pigment guanine), melanophores produce structural colours of blue and green. These colours are often extremely intense, because they are formed by refraction of light through the needlelike crystals of guanine. The blue and green refracted colours are often relatively pure, lacking the red and yellow rays, which have been absorbed by the black pigment (melanin) of the melanophores. Yellow, orange, and red colours are produced by erythrophores, cells containing the appropriate carotenoid pigments. Other colours are produced by combinations of melanophores, erythrophores, and iridocytes.

 

The major portion of the body of most fishes consists of muscles. Most of the mass is trunk musculature, the fin muscles usually being relatively small. The caudal fin is usually the most powerful fin, being moved by the trunk musculature. The body musculature is usually arranged in rows of chevron-shaped segments on each side. Contractions of these segments, each attached to adjacent vertebrae and vertebral processes, bends the body on the vertebral joint, producing successive undulations of the body, passing from the head to the tail, and producing driving strokes of the tail. It is the latter that provides the strong forward movement for most fishes.

 

The digestive system, in a functional sense, starts at the mouth, with the teeth used to capture prey or collect plant foods. Mouth shape and tooth structure vary greatly in fishes, depending on the kind of food normally eaten. Most fishes are predacious, feeding on small invertebrates or other fishes and have simple conical teeth on the jaws, on at least some of the bones of the roof of the mouth, and on special gill arch structures just in front of the esophagus. The latter are throat teeth. Most predacious fishes swallow their prey whole, and the teeth are used for grasping and holding prey, for orienting prey to be swallowed (head first) and for working the prey toward the esophagus. There are a variety of tooth types in fishes. Some fishes, such as sharks and piranhas, have cutting teeth for biting chunks out of their victims. A shark’s tooth, although superficially like that of a piranha, appears in many respects to be a modified scale, while that of the piranha is like that of other bony fishes, consisting of dentine and enamel. Parrot fishes have beaklike mouths with short incisor-like teeth for breaking off coral and have heavy pavementlike throat teeth for crushing the coral. Some catfishes have small brushlike teeth, arranged in rows on the jaws, for scraping plant and animal growth from rocks. Many fishes (such as the Cyprinidae or minnows) have no jaw teeth at all but have very strong throat teeth.

 

Some fishes gather planktonic food by straining it from their gill cavities with numerous elongate stiff rods (gill rakers) anchored by one end to the gill bars. The food collected on these rods is passed to the throat, where it is swallowed. Most fishes have only short gill rakers that help keep food particles from escaping out the mouth cavity into the gill chamber.

 

Once reaching the throat, food enters a short, often greatly distensible esophagus, a simple tube with a muscular wall leading into a stomach. The stomach varies greatly in fishes, depending upon the diet. In most predacious fishes it is a simple straight or curved tube or pouch with a muscular wall and a glandular lining. Food is largely digested there and leaves the stomach in liquid form.

 

Between the stomach and the intestine, ducts enter the digestive tube from the liver and pancreas. The liver is a large, clearly defined organ. The pancreas may be embedded in it, diffused through it, or broken into small parts spread along some of the intestine. The junction between the stomach and the intestine is marked by a muscular valve. Pyloric ceca (blind sacs) occur in some fishes at this junction and have a digestive or absorptive function or both.

 

The intestine itself is quite variable in length, depending upon the fish’s diet. It is short in predacious forms, sometimes no longer than the body cavity, but long in herbivorous forms, being coiled and several times longer than the entire length of the fish in some species of South American catfishes. The intestine is primarily an organ for absorbing nutrients into the bloodstream. The larger its internal surface, the greater its absorptive efficiency, and a spiral valve is one method of increasing its absorption surface.

 

Sharks, rays, chimaeras, lungfishes, surviving chondrosteans, holosteans, and even a few of the more primitive teleosts have a spiral valve or at least traces of it in the intestine. Most modern teleosts have increased the area of the intestinal walls by having numerous folds and villi (fingerlike projections) somewhat like those in humans. Undigested substances are passed to the exterior through the anus in most teleost fishes. In lungfishes, sharks, and rays, it is first passed through the cloaca, a common cavity receiving the intestinal opening and the ducts from the urogenital system.

 

Oxygen and carbon dioxide dissolve in water, and most fishes exchange dissolved oxygen and carbon dioxide in water by means of the gills. The gills lie behind and to the side of the mouth cavity and consist of fleshy filaments supported by the gill arches and filled with blood vessels, which give gills a bright red colour. Water taken in continuously through the mouth passes backward between the gill bars and over the gill filaments, where the exchange of gases takes place. The gills are protected by a gill cover in teleosts and many other fishes but by flaps of skin in sharks, rays, and some of the older fossil fish groups. The blood capillaries in the gill filaments are close to the gill surface to take up oxygen from the water and to give up excess carbon dioxide to the water.

 

Most modern fishes have a hydrostatic (ballast) organ, called the swim bladder, that lies in the body cavity just below the kidney and above the stomach and intestine. It originated as a diverticulum of the digestive canal. In advanced teleosts, especially the acanthopterygians, the bladder has lost its connection with the digestive tract, a condition called physoclistic. The connection has been retained (physostomous) by many relatively primitive teleosts. In several unrelated lines of fishes, the bladder has become specialized as a lung or, at least, as a highly vascularized accessory breathing organ. Some fishes with such accessory organs are obligate air breathers and will drown if denied access to the surface, even in well-oxygenated water. Fishes with a hydrostatic form of swim bladder can control their depth by regulating the amount of gas in the bladder. The gas, mostly oxygen, is secreted into the bladder by special glands, rendering the fish more buoyant; the gas is absorbed into the bloodstream by another special organ, reducing the overall buoyancy and allowing the fish to sink. Some deep-sea fishes may have oils, rather than gas, in the bladder. Other deep-sea and some bottom-living forms have much-reduced swim bladders or have lost the organ entirely.

 

The swim bladder of fishes follows the same developmental pattern as the lungs of land vertebrates. There is no doubt that the two structures have the same historical origin in primitive fishes. More or less intermediate forms still survive among the more primitive types of fishes, such as the lungfishes Lepidosiren and Protopterus.

 

The circulatory, or blood vascular, system consists of the heart, the arteries, the capillaries, and the veins. It is in the capillaries that the interchange of oxygen, carbon dioxide, nutrients, and other substances such as hormones and waste products takes place. The capillaries lead to the veins, which return the venous blood with its waste products to the heart, kidneys, and gills. There are two kinds of capillary beds: those in the gills and those in the rest of the body. The heart, a folded continuous muscular tube with three or four saclike enlargements, undergoes rhythmic contractions and receives venous blood in a sinus venosus. It passes the blood to an auricle and then into a thick muscular pump, the ventricle. From the ventricle the blood goes to a bulbous structure at the base of a ventral aorta just below the gills. The blood passes to the afferent (receiving) arteries of the gill arches and then to the gill capillaries. There waste gases are given off to the environment, and oxygen is absorbed. The oxygenated blood enters efferent (exuant) arteries of the gill arches and then flows into the dorsal aorta. From there blood is distributed to the tissues and organs of the body. One-way valves prevent backflow. The circulation of fishes thus differs from that of the reptiles, birds, and mammals in that oxygenated blood is not returned to the heart prior to distribution to the other parts of the body.

 

The primary excretory organ in fishes, as in other vertebrates, is the kidney. In fishes some excretion also takes place in the digestive tract, skin, and especially the gills (where ammonia is given off). Compared with land vertebrates, fishes have a special problem in maintaining their internal environment at a constant concentration of water and dissolved substances, such as salts. Proper balance of the internal environment (homeostasis) of a fish is in a great part maintained by the excretory system, especially the kidney.

 

The kidney, gills, and skin play an important role in maintaining a fish’s internal environment and checking the effects of osmosis. Marine fishes live in an environment in which the water around them has a greater concentration of salts than they can have inside their body and still maintain life. Freshwater fishes, on the other hand, live in water with a much lower concentration of salts than they require inside their bodies. Osmosis tends to promote the loss of water from the body of a marine fish and absorption of water by that of a freshwater fish. Mucus in the skin tends to slow the process but is not a sufficient barrier to prevent the movement of fluids through the permeable skin. When solutions on two sides of a permeable membrane have different concentrations of dissolved substances, water will pass through the membrane into the more concentrated solution, while the dissolved chemicals move into the area of lower concentration (diffusion).

 

The kidney of freshwater fishes is often larger in relation to body weight than that of marine fishes. In both groups the kidney excretes wastes from the body, but the kidney of freshwater fishes also excretes large amounts of water, counteracting the water absorbed through the skin. Freshwater fishes tend to lose salt to the environment and must replace it. They get some salt from their food, but the gills and skin inside the mouth actively absorb salt from water passed through the mouth. This absorption is performed by special cells capable of moving salts against the diffusion gradient. Freshwater fishes drink very little water and take in little water with their food.

 

Marine fishes must conserve water, and therefore their kidneys excrete little water. To maintain their water balance, marine fishes drink large quantities of seawater, retaining most of the water and excreting the salt. Most nitrogenous waste in marine fishes appears to be secreted by the gills as ammonia. Marine fishes can excrete salt by clusters of special cells (chloride cells) in the gills.

 

There are several teleosts—for example, the salmon—that travel between fresh water and seawater and must adjust to the reversal of osmotic gradients. They adjust their physiological processes by spending time (often surprisingly little time) in the intermediate brackish environment.

 

Marine hagfishes, sharks, and rays have osmotic concentrations in their blood about equal to that of seawater and so do not have to drink water nor perform much physiological work to maintain their osmotic balance. In sharks and rays the osmotic concentration is kept high by retention of urea in the blood. Freshwater sharks have a lowered concentration of urea in the blood.

 

Endocrine glands secrete their products into the bloodstream and body tissues and, along with the central nervous system, control and regulate many kinds of body functions. Cyclostomes have a well-developed endocrine system, and presumably it was well developed in the early Agnatha, ancestral to modern fishes. Although the endocrine system in fishes is similar to that of higher vertebrates, there are numerous differences in detail. The pituitary, the thyroid, the suprarenals, the adrenals, the pancreatic islets, the sex glands (ovaries and testes), the inner wall of the intestine, and the bodies of the ultimobranchial gland make up the endocrine system in fishes. There are some others whose function is not well understood. These organs regulate sexual activity and reproduction, growth, osmotic pressure, general metabolic activities such as the storage of fat and the utilization of foodstuffs, blood pressure, and certain aspects of skin colour. Many of these activities are also controlled in part by the central nervous system, which works with the endocrine system in maintaining the life of a fish. Some parts of the endocrine system are developmentally, and undoubtedly evolutionarily, derived from the nervous system.

 

As in all vertebrates, the nervous system of fishes is the primary mechanism coordinating body activities, as well as integrating these activities in the appropriate manner with stimuli from the environment. The central nervous system, consisting of the brain and spinal cord, is the primary integrating mechanism. The peripheral nervous system, consisting of nerves that connect the brain and spinal cord to various body organs, carries sensory information from special receptor organs such as the eyes, internal ears, nares (sense of smell), taste glands, and others to the integrating centres of the brain and spinal cord. The peripheral nervous system also carries information via different nerve cells from the integrating centres of the brain and spinal cord. This coded information is carried to the various organs and body systems, such as the skeletal muscular system, for appropriate action in response to the original external or internal stimulus. Another branch of the nervous system, the autonomic nervous system, helps to coordinate the activities of many glands and organs and is itself closely connected to the integrating centres of the brain.

 

The brain of the fish is divided into several anatomical and functional parts, all closely interconnected but each serving as the primary centre of integrating particular kinds of responses and activities. Several of these centres or parts are primarily associated with one type of sensory perception, such as sight, hearing, or smell (olfaction).

 

The sense of smell is important in almost all fishes. Certain eels with tiny eyes depend mostly on smell for location of food. The olfactory, or nasal, organ of fishes is located on the dorsal surface of the snout. The lining of the nasal organ has special sensory cells that perceive chemicals dissolved in the water, such as substances from food material, and send sensory information to the brain by way of the first cranial nerve. Odour also serves as an alarm system. Many fishes, especially various species of freshwater minnows, react with alarm to a chemical released from the skin of an injured member of their own species.

 

Many fishes have a well-developed sense of taste, and tiny pitlike taste buds or organs are located not only within their mouth cavities but also over their heads and parts of their body. Catfishes, which often have poor vision, have barbels (“whiskers”) that serve as supplementary taste organs, those around the mouth being actively used to search out food on the bottom. Some species of naturally blind cave fishes are especially well supplied with taste buds, which often cover most of their body surface.

 

Sight is extremely important in most fishes. The eye of a fish is basically like that of all other vertebrates, but the eyes of fishes are extremely varied in structure and adaptation. In general, fishes living in dark and dim water habitats have large eyes, unless they have specialized in some compensatory way so that another sense (such as smell) is dominant, in which case the eyes will often be reduced. Fishes living in brightly lighted shallow waters often will have relatively small but efficient eyes. Cyclostomes have somewhat less elaborate eyes than other fishes, with skin stretched over the eyeball perhaps making their vision somewhat less effective. Most fishes have a spherical lens and accommodate their vision to far or near subjects by moving the lens within the eyeball. A few sharks accommodate by changing the shape of the lens, as in land vertebrates. Those fishes that are heavily dependent upon the eyes have especially strong muscles for accommodation. Most fishes see well, despite the restrictions imposed by frequent turbidity of the water and by light refraction.

 

Fossil evidence suggests that colour vision evolved in fishes more than 300 million years ago, but not all living fishes have retained this ability. Experimental evidence indicates that many shallow-water fishes, if not all, have colour vision and see some colours especially well, but some bottom-dwelling shore fishes live in areas where the water is sufficiently deep to filter out most if not all colours, and these fishes apparently never see colours. When tested in shallow water, they apparently are unable to respond to colour differences.

 

Sound perception and balance are intimately associated senses in a fish. The organs of hearing are entirely internal, located within the skull, on each side of the brain and somewhat behind the eyes. Sound waves, especially those of low frequencies, travel readily through water and impinge directly upon the bones and fluids of the head and body, to be transmitted to the hearing organs. Fishes readily respond to sound; for example, a trout conditioned to escape by the approach of fishermen will take flight upon perceiving footsteps on a stream bank even if it cannot see a fisherman. Compared with humans, however, the range of sound frequencies heard by fishes is greatly restricted. Many fishes communicate with each other by producing sounds in their swim bladders, in their throats by rasping their teeth, and in other ways.

 

A fish or other vertebrate seldom has to rely on a single type of sensory information to determine the nature of the environment around it. A catfish uses taste and touch when examining a food object with its oral barbels. Like most other animals, fishes have many touch receptors over their body surface. Pain and temperature receptors also are present in fishes and presumably produce the same kind of information to a fish as to humans. Fishes react in a negative fashion to stimuli that would be painful to human beings, suggesting that they feel a sensation of pain.

 

An important sensory system in fishes that is absent in other vertebrates (except some amphibians) is the lateral line system. This consists of a series of heavily innervated small canals located in the skin and bone around the eyes, along the lower jaw, over the head, and down the mid-side of the body, where it is associated with the scales. Intermittently along these canals are located tiny sensory organs (pit organs) that apparently detect changes in pressure. The system allows a fish to sense changes in water currents and pressure, thereby helping the fish to orient itself to the various changes that occur in the physical environment.

  

Fish, any of approximately 34,000 species of vertebrate animals (phylum Chordata) found in the fresh and salt waters of the world. Living species range from the primitive jawless lampreys and hagfishes through the cartilaginous sharks, skates, and rays to the abundant and diverse bony fishes. Most fish species are cold-blooded; however, one species, the opah (Lampris guttatus), is warm-blooded.

 

The term fish is applied to a variety of vertebrates of several evolutionary lines. It describes a life-form rather than a taxonomic group. As members of the phylum Chordata, fish share certain features with other vertebrates. These features are gill slits at some point in the life cycle, a notochord, or skeletal supporting rod, a dorsal hollow nerve cord, and a tail. Living fishes represent some five classes, which are as distinct from one another as are the four classes of familiar air-breathing animals—amphibians, reptiles, birds, and mammals. For example, the jawless fishes (Agnatha) have gills in pouches and lack limb girdles. Extant agnathans are the lampreys and the hagfishes. As the name implies, the skeletons of fishes of the class Chondrichthyes (from chondr, “cartilage,” and ichthyes, “fish”) are made entirely of cartilage. Modern fish of this class lack a swim bladder, and their scales and teeth are made up of the same placoid material. Sharks, skates, and rays are examples of cartilaginous fishes. The bony fishes are by far the largest class. Examples range from the tiny seahorse to the 450-kg (1,000-pound) blue marlin, from the flattened soles and flounders to the boxy puffers and ocean sunfishes. Unlike the scales of the cartilaginous fishes, those of bony fishes, when present, grow throughout life and are made up of thin overlapping plates of bone. Bony fishes also have an operculum that covers the gill slits.

 

The study of fishes, the science of ichthyology, is of broad importance. Fishes are of interest to humans for many reasons, the most important being their relationship with and dependence on the environment. A more obvious reason for interest in fishes is their role as a moderate but important part of the world’s food supply. This resource, once thought unlimited, is now realized to be finite and in delicate balance with the biological, chemical, and physical factors of the aquatic environment. Overfishing, pollution, and alteration of the environment are the chief enemies of proper fisheries management, both in fresh waters and in the ocean. (For a detailed discussion of the technology and economics of fisheries, see commercial fishing.) Another practical reason for studying fishes is their use in disease control. As predators on mosquito larvae, they help curb malaria and other mosquito-borne diseases.

 

Fishes are valuable laboratory animals in many aspects of medical and biological research. For example, the readiness of many fishes to acclimate to captivity has allowed biologists to study behaviour, physiology, and even ecology under relatively natural conditions. Fishes have been especially important in the study of animal behaviour, where research on fishes has provided a broad base for the understanding of the more flexible behaviour of the higher vertebrates. The zebra fish is used as a model in studies of gene expression.

 

There are aesthetic and recreational reasons for an interest in fishes. Millions of people keep live fishes in home aquariums for the simple pleasure of observing the beauty and behaviour of animals otherwise unfamiliar to them. Aquarium fishes provide a personal challenge to many aquarists, allowing them to test their ability to keep a small section of the natural environment in their homes. Sportfishing is another way of enjoying the natural environment, also indulged in by millions of people every year. Interest in aquarium fishes and sportfishing supports multimillion-dollar industries throughout the world.

 

Fishes have been in existence for more than 450 million years, during which time they have evolved repeatedly to fit into almost every conceivable type of aquatic habitat. In a sense, land vertebrates are simply highly modified fishes: when fishes colonized the land habitat, they became tetrapod (four-legged) land vertebrates. The popular conception of a fish as a slippery, streamlined aquatic animal that possesses fins and breathes by gills applies to many fishes, but far more fishes deviate from that conception than conform to it. For example, the body is elongate in many forms and greatly shortened in others; the body is flattened in some (principally in bottom-dwelling fishes) and laterally compressed in many others; the fins may be elaborately extended, forming intricate shapes, or they may be reduced or even lost; and the positions of the mouth, eyes, nostrils, and gill openings vary widely. Air breathers have appeared in several evolutionary lines.

 

Many fishes are cryptically coloured and shaped, closely matching their respective environments; others are among the most brilliantly coloured of all organisms, with a wide range of hues, often of striking intensity, on a single individual. The brilliance of pigments may be enhanced by the surface structure of the fish, so that it almost seems to glow. A number of unrelated fishes have actual light-producing organs. Many fishes are able to alter their coloration—some for the purpose of camouflage, others for the enhancement of behavioral signals.

 

Fishes range in adult length from less than 10 mm (0.4 inch) to more than 20 metres (60 feet) and in weight from about 1.5 grams (less than 0.06 ounce) to many thousands of kilograms. Some live in shallow thermal springs at temperatures slightly above 42 °C (100 °F), others in cold Arctic seas a few degrees below 0 °C (32 °F) or in cold deep waters more than 4,000 metres (13,100 feet) beneath the ocean surface. The structural and, especially, the physiological adaptations for life at such extremes are relatively poorly known and provide the scientifically curious with great incentive for study.

 

Almost all natural bodies of water bear fish life, the exceptions being very hot thermal ponds and extremely salt-alkaline lakes, such as the Dead Sea in Asia and the Great Salt Lake in North America. The present distribution of fishes is a result of the geological history and development of Earth as well as the ability of fishes to undergo evolutionary change and to adapt to the available habitats. Fishes may be seen to be distributed according to habitat and according to geographical area. Major habitat differences are marine and freshwater. For the most part, the fishes in a marine habitat differ from those in a freshwater habitat, even in adjacent areas, but some, such as the salmon, migrate from one to the other. The freshwater habitats may be seen to be of many kinds. Fishes found in mountain torrents, Arctic lakes, tropical lakes, temperate streams, and tropical rivers will all differ from each other, both in obvious gross structure and in physiological attributes. Even in closely adjacent habitats where, for example, a tropical mountain torrent enters a lowland stream, the fish fauna will differ. The marine habitats can be divided into deep ocean floors (benthic), mid-water oceanic (bathypelagic), surface oceanic (pelagic), rocky coast, sandy coast, muddy shores, bays, estuaries, and others. Also, for example, rocky coastal shores in tropical and temperate regions will have different fish faunas, even when such habitats occur along the same coastline.

 

Although much is known about the present geographical distribution of fishes, far less is known about how that distribution came about. Many parts of the fish fauna of the fresh waters of North America and Eurasia are related and undoubtedly have a common origin. The faunas of Africa and South America are related, extremely old, and probably an expression of the drifting apart of the two continents. The fauna of southern Asia is related to that of Central Asia, and some of it appears to have entered Africa. The extremely large shore-fish faunas of the Indian and tropical Pacific oceans comprise a related complex, but the tropical shore fauna of the Atlantic, although containing Indo-Pacific components, is relatively limited and probably younger. The Arctic and Antarctic marine faunas are quite different from each other. The shore fauna of the North Pacific is quite distinct, and that of the North Atlantic more limited and probably younger. Pelagic oceanic fishes, especially those in deep waters, are similar the world over, showing little geographical isolation in terms of family groups. The deep oceanic habitat is very much the same throughout the world, but species differences do exist, showing geographical areas determined by oceanic currents and water masses.

 

All aspects of the life of a fish are closely correlated with adaptation to the total environment, physical, chemical, and biological. In studies, all the interdependent aspects of fish, such as behaviour, locomotion, reproduction, and physical and physiological characteristics, must be taken into account.

 

Correlated with their adaptation to an extremely wide variety of habitats is the extremely wide variety of life cycles that fishes display. The great majority hatch from relatively small eggs a few days to several weeks or more after the eggs are scattered in the water. Newly hatched young are still partially undeveloped and are called larvae until body structures such as fins, skeleton, and some organs are fully formed. Larval life is often very short, usually less than a few weeks, but it can be very long, some lampreys continuing as larvae for at least five years. Young and larval fishes, before reaching sexual maturity, must grow considerably, and their small size and other factors often dictate that they live in a habitat different than that of the adults. For example, most tropical marine shore fishes have pelagic larvae. Larval food also is different, and larval fishes often live in shallow waters, where they may be less exposed to predators.

 

After a fish reaches adult size, the length of its life is subject to many factors, such as innate rates of aging, predation pressure, and the nature of the local climate. The longevity of a species in the protected environment of an aquarium may have nothing to do with how long members of that species live in the wild. Many small fishes live only one to three years at the most. In some species, however, individuals may live as long as 10 or 20 or even 100 years.

 

Fish behaviour is a complicated and varied subject. As in almost all animals with a central nervous system, the nature of a response of an individual fish to stimuli from its environment depends upon the inherited characteristics of its nervous system, on what it has learned from past experience, and on the nature of the stimuli. Compared with the variety of human responses, however, that of a fish is stereotyped, not subject to much modification by “thought” or learning, and investigators must guard against anthropomorphic interpretations of fish behaviour.

 

Fishes perceive the world around them by the usual senses of sight, smell, hearing, touch, and taste and by special lateral line water-current detectors. In the few fishes that generate electric fields, a process that might best be called electrolocation aids in perception. One or another of these senses often is emphasized at the expense of others, depending upon the fish’s other adaptations. In fishes with large eyes, the sense of smell may be reduced; others, with small eyes, hunt and feed primarily by smell (such as some eels).

 

Specialized behaviour is primarily concerned with the three most important activities in the fish’s life: feeding, reproduction, and escape from enemies. Schooling behaviour of sardines on the high seas, for instance, is largely a protective device to avoid enemies, but it is also associated with and modified by their breeding and feeding requirements. Predatory fishes are often solitary, lying in wait to dart suddenly after their prey, a kind of locomotion impossible for beaked parrot fishes, which feed on coral, swimming in small groups from one coral head to the next. In addition, some predatory fishes that inhabit pelagic environments, such as tunas, often school.

 

Sleep in fishes, all of which lack true eyelids, consists of a seemingly listless state in which the fish maintains its balance but moves slowly. If attacked or disturbed, most can dart away. A few kinds of fishes lie on the bottom to sleep. Most catfishes, some loaches, and some eels and electric fishes are strictly nocturnal, being active and hunting for food during the night and retiring during the day to holes, thick vegetation, or other protective parts of the environment.

 

Communication between members of a species or between members of two or more species often is extremely important, especially in breeding behaviour (see below Reproduction). The mode of communication may be visual, as between the small so-called cleaner fish and a large fish of a very different species. The larger fish often allows the cleaner to enter its mouth to remove gill parasites. The cleaner is recognized by its distinctive colour and actions and therefore is not eaten, even if the larger fish is normally a predator. Communication is often chemical, signals being sent by specific chemicals called pheromones.

 

Many fishes have a streamlined body and swim freely in open water. Fish locomotion is closely correlated with habitat and ecological niche (the general position of the animal to its environment).

 

Many fishes in both marine and fresh waters swim at the surface and have mouths adapted to feed best (and sometimes only) at the surface. Often such fishes are long and slender, able to dart at surface insects or at other surface fishes and in turn to dart away from predators; needlefishes, halfbeaks, and topminnows (such as killifish and mosquito fish) are good examples. Oceanic flying fishes escape their predators by gathering speed above the water surface, with the lower lobe of the tail providing thrust in the water. They then glide hundreds of yards on enlarged, winglike pectoral and pelvic fins. South American freshwater flying fishes escape their enemies by jumping and propelling their strongly keeled bodies out of the water.

 

So-called mid-water swimmers, the most common type of fish, are of many kinds and live in many habitats. The powerful fusiform tunas and the trouts, for example, are adapted for strong, fast swimming, the tunas to capture prey speedily in the open ocean and the trouts to cope with the swift currents of streams and rivers. The trout body form is well adapted to many habitats. Fishes that live in relatively quiet waters such as bays or lake shores or slow rivers usually are not strong, fast swimmers but are capable of short, quick bursts of speed to escape a predator. Many of these fishes have their sides flattened, examples being the sunfish and the freshwater angelfish of aquarists. Fish associated with the bottom or substrate usually are slow swimmers. Open-water plankton-feeding fishes almost always remain fusiform and are capable of rapid, strong movement (for example, sardines and herrings of the open ocean and also many small minnows of streams and lakes).

 

Bottom-living fishes are of many kinds and have undergone many types of modification of their body shape and swimming habits. Rays, which evolved from strong-swimming mid-water sharks, usually stay close to the bottom and move by undulating their large pectoral fins. Flounders live in a similar habitat and move over the bottom by undulating the entire body. Many bottom fishes dart from place to place, resting on the bottom between movements, a motion common in gobies. One goby relative, the mudskipper, has taken to living at the edge of pools along the shore of muddy mangrove swamps. It escapes its enemies by flipping rapidly over the mud, out of the water. Some catfishes, synbranchid eels, the so-called climbing perch, and a few other fishes venture out over damp ground to find more promising waters than those that they left. They move by wriggling their bodies, sometimes using strong pectoral fins; most have accessory air-breathing organs. Many bottom-dwelling fishes live in mud holes or rocky crevices. Marine eels and gobies commonly are found in such habitats and for the most part venture far beyond their cavelike homes. Some bottom dwellers, such as the clingfishes (Gobiesocidae), have developed powerful adhesive disks that enable them to remain in place on the substrate in areas such as rocky coasts, where the action of the waves is great.

 

The methods of reproduction in fishes are varied, but most fishes lay a large number of small eggs, fertilized and scattered outside of the body. The eggs of pelagic fishes usually remain suspended in the open water. Many shore and freshwater fishes lay eggs on the bottom or among plants. Some have adhesive eggs. The mortality of the young and especially of the eggs is very high, and often only a few individuals grow to maturity out of hundreds, thousands, and in some cases millions of eggs laid.

 

Males produce sperm, usually as a milky white substance called milt, in two (sometimes one) testes within the body cavity. In bony fishes a sperm duct leads from each testis to a urogenital opening behind the vent or anus. In sharks and rays and in cyclostomes the duct leads to a cloaca. Sometimes the pelvic fins are modified to help transmit the milt to the eggs at the female’s vent or on the substrate where the female has placed them. Sometimes accessory organs are used to fertilize females internally—for example, the claspers of many sharks and rays.

 

In the females the eggs are formed in two ovaries (sometimes only one) and pass through the ovaries to the urogenital opening and to the outside. In some fishes the eggs are fertilized internally but are shed before development takes place. Members of about a dozen families each of bony fishes (teleosts) and sharks bear live young. Many skates and rays also bear live young. In some bony fishes the eggs simply develop within the female, the young emerging when the eggs hatch (ovoviviparous). Others develop within the ovary and are nourished by ovarian tissues after hatching (viviparous). There are also other methods utilized by fishes to nourish young within the female. In all live-bearers the young are born at a relatively large size and are few in number. In one family of primarily marine fishes, the surfperches from the Pacific coast of North America, Japan, and Korea, the males of at least one species are born sexually mature, although they are not fully grown.

 

Some fishes are hermaphroditic—an individual producing both sperm and eggs, usually at different stages of its life. Self-fertilization, however, is probably rare.

 

Successful reproduction and, in many cases, defense of the eggs and the young are assured by rather stereotypical but often elaborate courtship and parental behaviour, either by the male or the female or both. Some fishes prepare nests by hollowing out depressions in the sand bottom (cichlids, for example), build nests with plant materials and sticky threads excreted by the kidneys (sticklebacks), or blow a cluster of mucus-covered bubbles at the water surface (gouramis). The eggs are laid in these structures. Some varieties of cichlids and catfishes incubate eggs in their mouths.

 

Some fishes, such as salmon, undergo long migrations from the ocean and up large rivers to spawn in the gravel beds where they themselves hatched (anadromous fishes). Some, such as the freshwater eels (family Anguillidae), live and grow to maturity in fresh water and migrate to the sea to spawn (catadromous fishes). Other fishes undertake shorter migrations from lakes into streams, within the ocean, or enter spawning habitats that they do not ordinarily occupy in other ways.

 

The basic structure and function of the fish body are similar to those of all other vertebrates. The usual four types of tissues are present: surface or epithelial, connective (bone, cartilage, and fibrous tissues, as well as their derivative, blood), nerve, and muscle tissues. In addition, the fish’s organs and organ systems parallel those of other vertebrates.

 

The typical fish body is streamlined and spindle-shaped, with an anterior head, a gill apparatus, and a heart, the latter lying in the midline just below the gill chamber. The body cavity, containing the vital organs, is situated behind the head in the lower anterior part of the body. The anus usually marks the posterior termination of the body cavity and most often occurs just in front of the base of the anal fin. The spinal cord and vertebral column continue from the posterior part of the head to the base of the tail fin, passing dorsal to the body cavity and through the caudal (tail) region behind the body cavity. Most of the body is of muscular tissue, a high proportion of which is necessitated by swimming. In the course of evolution this basic body plan has been modified repeatedly into the many varieties of fish shapes that exist today.

 

The skeleton forms an integral part of the fish’s locomotion system, as well as serving to protect vital parts. The internal skeleton consists of the skull bones (except for the roofing bones of the head, which are really part of the external skeleton), the vertebral column, and the fin supports (fin rays). The fin supports are derived from the external skeleton but will be treated here because of their close functional relationship to the internal skeleton. The internal skeleton of cyclostomes, sharks, and rays is of cartilage; that of many fossil groups and some primitive living fishes is mostly of cartilage but may include some bone. In place of the vertebral column, the earliest vertebrates had a fully developed notochord, a flexible stiff rod of viscous cells surrounded by a strong fibrous sheath. During the evolution of modern fishes the rod was replaced in part by cartilage and then by ossified cartilage. Sharks and rays retain a cartilaginous vertebral column; bony fishes have spool-shaped vertebrae that in the more primitive living forms only partially replace the notochord. The skull, including the gill arches and jaws of bony fishes, is fully, or at least partially, ossified. That of sharks and rays remains cartilaginous, at times partially replaced by calcium deposits but never by true bone.

 

The supportive elements of the fins (basal or radial bones or both) have changed greatly during fish evolution. Some of these changes are described in the section below (Evolution and paleontology). Most fishes possess a single dorsal fin on the midline of the back. Many have two and a few have three dorsal fins. The other fins are the single tail and anal fins and paired pelvic and pectoral fins. A small fin, the adipose fin, with hairlike fin rays, occurs in many of the relatively primitive teleosts (such as trout) on the back near the base of the caudal fin.

 

The skin of a fish must serve many functions. It aids in maintaining the osmotic balance, provides physical protection for the body, is the site of coloration, contains sensory receptors, and, in some fishes, functions in respiration. Mucous glands, which aid in maintaining the water balance and offer protection from bacteria, are extremely numerous in fish skin, especially in cyclostomes and teleosts. Since mucous glands are present in the modern lampreys, it is reasonable to assume that they were present in primitive fishes, such as the ancient Silurian and Devonian agnathans. Protection from abrasion and predation is another function of the fish skin, and dermal (skin) bone arose early in fish evolution in response to this need. It is thought that bone first evolved in skin and only later invaded the cartilaginous areas of the fish’s body, to provide additional support and protection. There is some argument as to which came first, cartilage or bone, and fossil evidence does not settle the question. In any event, dermal bone has played an important part in fish evolution and has different characteristics in different groups of fishes. Several groups are characterized at least in part by the kind of bony scales they possess.

 

Scales have played an important part in the evolution of fishes. Primitive fishes usually had thick bony plates or thick scales in several layers of bone, enamel, and related substances. Modern teleost fishes have scales of bone, which, while still protective, allow much more freedom of motion in the body. A few modern teleosts (some catfishes, sticklebacks, and others) have secondarily acquired bony plates in the skin. Modern and early sharks possessed placoid scales, a relatively primitive type of scale with a toothlike structure, consisting of an outside layer of enamel-like substance (vitrodentine), an inner layer of dentine, and a pulp cavity containing nerves and blood vessels. Primitive bony fishes had thick scales of either the ganoid or the cosmoid type. Cosmoid scales have a hard, enamel-like outer layer, an inner layer of cosmine (a form of dentine), and then a layer of vascular bone (isopedine). In ganoid scales the hard outer layer is different chemically and is called ganoin. Under this is a cosminelike layer and then a vascular bony layer. The thin, translucent bony scales of modern fishes, called cycloid and ctenoid (the latter distinguished by serrations at the edges), lack enameloid and dentine layers.

 

Skin has several other functions in fishes. It is well supplied with nerve endings and presumably receives tactile, thermal, and pain stimuli. Skin is also well supplied with blood vessels. Some fishes breathe in part through the skin, by the exchange of oxygen and carbon dioxide between the surrounding water and numerous small blood vessels near the skin surface.

 

Skin serves as protection through the control of coloration. Fishes exhibit an almost limitless range of colours. The colours often blend closely with the surroundings, effectively hiding the animal. Many fishes use bright colours for territorial advertisement or as recognition marks for other members of their own species, or sometimes for members of other species. Many fishes can change their colour to a greater or lesser degree, by movement of pigment within the pigment cells (chromatophores). Black pigment cells (melanophores), of almost universal occurrence in fishes, are often juxtaposed with other pigment cells. When placed beneath iridocytes or leucophores (bearing the silvery or white pigment guanine), melanophores produce structural colours of blue and green. These colours are often extremely intense, because they are formed by refraction of light through the needlelike crystals of guanine. The blue and green refracted colours are often relatively pure, lacking the red and yellow rays, which have been absorbed by the black pigment (melanin) of the melanophores. Yellow, orange, and red colours are produced by erythrophores, cells containing the appropriate carotenoid pigments. Other colours are produced by combinations of melanophores, erythrophores, and iridocytes.

 

The major portion of the body of most fishes consists of muscles. Most of the mass is trunk musculature, the fin muscles usually being relatively small. The caudal fin is usually the most powerful fin, being moved by the trunk musculature. The body musculature is usually arranged in rows of chevron-shaped segments on each side. Contractions of these segments, each attached to adjacent vertebrae and vertebral processes, bends the body on the vertebral joint, producing successive undulations of the body, passing from the head to the tail, and producing driving strokes of the tail. It is the latter that provides the strong forward movement for most fishes.

 

The digestive system, in a functional sense, starts at the mouth, with the teeth used to capture prey or collect plant foods. Mouth shape and tooth structure vary greatly in fishes, depending on the kind of food normally eaten. Most fishes are predacious, feeding on small invertebrates or other fishes and have simple conical teeth on the jaws, on at least some of the bones of the roof of the mouth, and on special gill arch structures just in front of the esophagus. The latter are throat teeth. Most predacious fishes swallow their prey whole, and the teeth are used for grasping and holding prey, for orienting prey to be swallowed (head first) and for working the prey toward the esophagus. There are a variety of tooth types in fishes. Some fishes, such as sharks and piranhas, have cutting teeth for biting chunks out of their victims. A shark’s tooth, although superficially like that of a piranha, appears in many respects to be a modified scale, while that of the piranha is like that of other bony fishes, consisting of dentine and enamel. Parrot fishes have beaklike mouths with short incisor-like teeth for breaking off coral and have heavy pavementlike throat teeth for crushing the coral. Some catfishes have small brushlike teeth, arranged in rows on the jaws, for scraping plant and animal growth from rocks. Many fishes (such as the Cyprinidae or minnows) have no jaw teeth at all but have very strong throat teeth.

 

Some fishes gather planktonic food by straining it from their gill cavities with numerous elongate stiff rods (gill rakers) anchored by one end to the gill bars. The food collected on these rods is passed to the throat, where it is swallowed. Most fishes have only short gill rakers that help keep food particles from escaping out the mouth cavity into the gill chamber.

 

Once reaching the throat, food enters a short, often greatly distensible esophagus, a simple tube with a muscular wall leading into a stomach. The stomach varies greatly in fishes, depending upon the diet. In most predacious fishes it is a simple straight or curved tube or pouch with a muscular wall and a glandular lining. Food is largely digested there and leaves the stomach in liquid form.

 

Between the stomach and the intestine, ducts enter the digestive tube from the liver and pancreas. The liver is a large, clearly defined organ. The pancreas may be embedded in it, diffused through it, or broken into small parts spread along some of the intestine. The junction between the stomach and the intestine is marked by a muscular valve. Pyloric ceca (blind sacs) occur in some fishes at this junction and have a digestive or absorptive function or both.

 

The intestine itself is quite variable in length, depending upon the fish’s diet. It is short in predacious forms, sometimes no longer than the body cavity, but long in herbivorous forms, being coiled and several times longer than the entire length of the fish in some species of South American catfishes. The intestine is primarily an organ for absorbing nutrients into the bloodstream. The larger its internal surface, the greater its absorptive efficiency, and a spiral valve is one method of increasing its absorption surface.

 

Sharks, rays, chimaeras, lungfishes, surviving chondrosteans, holosteans, and even a few of the more primitive teleosts have a spiral valve or at least traces of it in the intestine. Most modern teleosts have increased the area of the intestinal walls by having numerous folds and villi (fingerlike projections) somewhat like those in humans. Undigested substances are passed to the exterior through the anus in most teleost fishes. In lungfishes, sharks, and rays, it is first passed through the cloaca, a common cavity receiving the intestinal opening and the ducts from the urogenital system.

 

Oxygen and carbon dioxide dissolve in water, and most fishes exchange dissolved oxygen and carbon dioxide in water by means of the gills. The gills lie behind and to the side of the mouth cavity and consist of fleshy filaments supported by the gill arches and filled with blood vessels, which give gills a bright red colour. Water taken in continuously through the mouth passes backward between the gill bars and over the gill filaments, where the exchange of gases takes place. The gills are protected by a gill cover in teleosts and many other fishes but by flaps of skin in sharks, rays, and some of the older fossil fish groups. The blood capillaries in the gill filaments are close to the gill surface to take up oxygen from the water and to give up excess carbon dioxide to the water.

 

Most modern fishes have a hydrostatic (ballast) organ, called the swim bladder, that lies in the body cavity just below the kidney and above the stomach and intestine. It originated as a diverticulum of the digestive canal. In advanced teleosts, especially the acanthopterygians, the bladder has lost its connection with the digestive tract, a condition called physoclistic. The connection has been retained (physostomous) by many relatively primitive teleosts. In several unrelated lines of fishes, the bladder has become specialized as a lung or, at least, as a highly vascularized accessory breathing organ. Some fishes with such accessory organs are obligate air breathers and will drown if denied access to the surface, even in well-oxygenated water. Fishes with a hydrostatic form of swim bladder can control their depth by regulating the amount of gas in the bladder. The gas, mostly oxygen, is secreted into the bladder by special glands, rendering the fish more buoyant; the gas is absorbed into the bloodstream by another special organ, reducing the overall buoyancy and allowing the fish to sink. Some deep-sea fishes may have oils, rather than gas, in the bladder. Other deep-sea and some bottom-living forms have much-reduced swim bladders or have lost the organ entirely.

 

The swim bladder of fishes follows the same developmental pattern as the lungs of land vertebrates. There is no doubt that the two structures have the same historical origin in primitive fishes. More or less intermediate forms still survive among the more primitive types of fishes, such as the lungfishes Lepidosiren and Protopterus.

 

The circulatory, or blood vascular, system consists of the heart, the arteries, the capillaries, and the veins. It is in the capillaries that the interchange of oxygen, carbon dioxide, nutrients, and other substances such as hormones and waste products takes place. The capillaries lead to the veins, which return the venous blood with its waste products to the heart, kidneys, and gills. There are two kinds of capillary beds: those in the gills and those in the rest of the body. The heart, a folded continuous muscular tube with three or four saclike enlargements, undergoes rhythmic contractions and receives venous blood in a sinus venosus. It passes the blood to an auricle and then into a thick muscular pump, the ventricle. From the ventricle the blood goes to a bulbous structure at the base of a ventral aorta just below the gills. The blood passes to the afferent (receiving) arteries of the gill arches and then to the gill capillaries. There waste gases are given off to the environment, and oxygen is absorbed. The oxygenated blood enters efferent (exuant) arteries of the gill arches and then flows into the dorsal aorta. From there blood is distributed to the tissues and organs of the body. One-way valves prevent backflow. The circulation of fishes thus differs from that of the reptiles, birds, and mammals in that oxygenated blood is not returned to the heart prior to distribution to the other parts of the body.

 

The primary excretory organ in fishes, as in other vertebrates, is the kidney. In fishes some excretion also takes place in the digestive tract, skin, and especially the gills (where ammonia is given off). Compared with land vertebrates, fishes have a special problem in maintaining their internal environment at a constant concentration of water and dissolved substances, such as salts. Proper balance of the internal environment (homeostasis) of a fish is in a great part maintained by the excretory system, especially the kidney.

 

The kidney, gills, and skin play an important role in maintaining a fish’s internal environment and checking the effects of osmosis. Marine fishes live in an environment in which the water around them has a greater concentration of salts than they can have inside their body and still maintain life. Freshwater fishes, on the other hand, live in water with a much lower concentration of salts than they require inside their bodies. Osmosis tends to promote the loss of water from the body of a marine fish and absorption of water by that of a freshwater fish. Mucus in the skin tends to slow the process but is not a sufficient barrier to prevent the movement of fluids through the permeable skin. When solutions on two sides of a permeable membrane have different concentrations of dissolved substances, water will pass through the membrane into the more concentrated solution, while the dissolved chemicals move into the area of lower concentration (diffusion).

 

The kidney of freshwater fishes is often larger in relation to body weight than that of marine fishes. In both groups the kidney excretes wastes from the body, but the kidney of freshwater fishes also excretes large amounts of water, counteracting the water absorbed through the skin. Freshwater fishes tend to lose salt to the environment and must replace it. They get some salt from their food, but the gills and skin inside the mouth actively absorb salt from water passed through the mouth. This absorption is performed by special cells capable of moving salts against the diffusion gradient. Freshwater fishes drink very little water and take in little water with their food.

 

Marine fishes must conserve water, and therefore their kidneys excrete little water. To maintain their water balance, marine fishes drink large quantities of seawater, retaining most of the water and excreting the salt. Most nitrogenous waste in marine fishes appears to be secreted by the gills as ammonia. Marine fishes can excrete salt by clusters of special cells (chloride cells) in the gills.

 

There are several teleosts—for example, the salmon—that travel between fresh water and seawater and must adjust to the reversal of osmotic gradients. They adjust their physiological processes by spending time (often surprisingly little time) in the intermediate brackish environment.

 

Marine hagfishes, sharks, and rays have osmotic concentrations in their blood about equal to that of seawater and so do not have to drink water nor perform much physiological work to maintain their osmotic balance. In sharks and rays the osmotic concentration is kept high by retention of urea in the blood. Freshwater sharks have a lowered concentration of urea in the blood.

 

Endocrine glands secrete their products into the bloodstream and body tissues and, along with the central nervous system, control and regulate many kinds of body functions. Cyclostomes have a well-developed endocrine system, and presumably it was well developed in the early Agnatha, ancestral to modern fishes. Although the endocrine system in fishes is similar to that of higher vertebrates, there are numerous differences in detail. The pituitary, the thyroid, the suprarenals, the adrenals, the pancreatic islets, the sex glands (ovaries and testes), the inner wall of the intestine, and the bodies of the ultimobranchial gland make up the endocrine system in fishes. There are some others whose function is not well understood. These organs regulate sexual activity and reproduction, growth, osmotic pressure, general metabolic activities such as the storage of fat and the utilization of foodstuffs, blood pressure, and certain aspects of skin colour. Many of these activities are also controlled in part by the central nervous system, which works with the endocrine system in maintaining the life of a fish. Some parts of the endocrine system are developmentally, and undoubtedly evolutionarily, derived from the nervous system.

 

As in all vertebrates, the nervous system of fishes is the primary mechanism coordinating body activities, as well as integrating these activities in the appropriate manner with stimuli from the environment. The central nervous system, consisting of the brain and spinal cord, is the primary integrating mechanism. The peripheral nervous system, consisting of nerves that connect the brain and spinal cord to various body organs, carries sensory information from special receptor organs such as the eyes, internal ears, nares (sense of smell), taste glands, and others to the integrating centres of the brain and spinal cord. The peripheral nervous system also carries information via different nerve cells from the integrating centres of the brain and spinal cord. This coded information is carried to the various organs and body systems, such as the skeletal muscular system, for appropriate action in response to the original external or internal stimulus. Another branch of the nervous system, the autonomic nervous system, helps to coordinate the activities of many glands and organs and is itself closely connected to the integrating centres of the brain.

 

The brain of the fish is divided into several anatomical and functional parts, all closely interconnected but each serving as the primary centre of integrating particular kinds of responses and activities. Several of these centres or parts are primarily associated with one type of sensory perception, such as sight, hearing, or smell (olfaction).

 

The sense of smell is important in almost all fishes. Certain eels with tiny eyes depend mostly on smell for location of food. The olfactory, or nasal, organ of fishes is located on the dorsal surface of the snout. The lining of the nasal organ has special sensory cells that perceive chemicals dissolved in the water, such as substances from food material, and send sensory information to the brain by way of the first cranial nerve. Odour also serves as an alarm system. Many fishes, especially various species of freshwater minnows, react with alarm to a chemical released from the skin of an injured member of their own species.

 

Many fishes have a well-developed sense of taste, and tiny pitlike taste buds or organs are located not only within their mouth cavities but also over their heads and parts of their body. Catfishes, which often have poor vision, have barbels (“whiskers”) that serve as supplementary taste organs, those around the mouth being actively used to search out food on the bottom. Some species of naturally blind cave fishes are especially well supplied with taste buds, which often cover most of their body surface.

 

Sight is extremely important in most fishes. The eye of a fish is basically like that of all other vertebrates, but the eyes of fishes are extremely varied in structure and adaptation. In general, fishes living in dark and dim water habitats have large eyes, unless they have specialized in some compensatory way so that another sense (such as smell) is dominant, in which case the eyes will often be reduced. Fishes living in brightly lighted shallow waters often will have relatively small but efficient eyes. Cyclostomes have somewhat less elaborate eyes than other fishes, with skin stretched over the eyeball perhaps making their vision somewhat less effective. Most fishes have a spherical lens and accommodate their vision to far or near subjects by moving the lens within the eyeball. A few sharks accommodate by changing the shape of the lens, as in land vertebrates. Those fishes that are heavily dependent upon the eyes have especially strong muscles for accommodation. Most fishes see well, despite the restrictions imposed by frequent turbidity of the water and by light refraction.

 

Fossil evidence suggests that colour vision evolved in fishes more than 300 million years ago, but not all living fishes have retained this ability. Experimental evidence indicates that many shallow-water fishes, if not all, have colour vision and see some colours especially well, but some bottom-dwelling shore fishes live in areas where the water is sufficiently deep to filter out most if not all colours, and these fishes apparently never see colours. When tested in shallow water, they apparently are unable to respond to colour differences.

 

Sound perception and balance are intimately associated senses in a fish. The organs of hearing are entirely internal, located within the skull, on each side of the brain and somewhat behind the eyes. Sound waves, especially those of low frequencies, travel readily through water and impinge directly upon the bones and fluids of the head and body, to be transmitted to the hearing organs. Fishes readily respond to sound; for example, a trout conditioned to escape by the approach of fishermen will take flight upon perceiving footsteps on a stream bank even if it cannot see a fisherman. Compared with humans, however, the range of sound frequencies heard by fishes is greatly restricted. Many fishes communicate with each other by producing sounds in their swim bladders, in their throats by rasping their teeth, and in other ways.

 

A fish or other vertebrate seldom has to rely on a single type of sensory information to determine the nature of the environment around it. A catfish uses taste and touch when examining a food object with its oral barbels. Like most other animals, fishes have many touch receptors over their body surface. Pain and temperature receptors also are present in fishes and presumably produce the same kind of information to a fish as to humans. Fishes react in a negative fashion to stimuli that would be painful to human beings, suggesting that they feel a sensation of pain.

 

An important sensory system in fishes that is absent in other vertebrates (except some amphibians) is the lateral line system. This consists of a series of heavily innervated small canals located in the skin and bone around the eyes, along the lower jaw, over the head, and down the mid-side of the body, where it is associated with the scales. Intermittently along these canals are located tiny sensory organs (pit organs) that apparently detect changes in pressure. The system allows a fish to sense changes in water currents and pressure, thereby helping the fish to orient itself to the various changes that occur in the physical environment.

  

Go to Page with image in the Internet Archive

Title: United States Naval Medical Bulletin Vol. 20, Nos. 1-6, 1924

Creator: U.S. Navy. Bureau of Medicine and Surgery

Publisher:

Sponsor:

Contributor:

Date: 1924-01

Language: eng

  

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Table of Contents</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> Number 1</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> PREFACE -------------------------------- - - ------ ------- V</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTICE TO SERVICE CONTRIBUTORS____________________________ VI</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SPECIAL ARTICLES:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Climatic Bubo.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander C. S. Butler, Medical Corps, U. S. Navy______ 1</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTES ON 350 APPENDECTOMIES.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. Commander Lucius W. Johnson, Medical Corps, U. S .. Navy------------------------

-- 7</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">CLINICAL TRIAL OF THE ELLIS TEST FOR TUBERCULOSIS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. D. Ferguson, Medical Corps, U. S. Navy____________ 17</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">CANCER IN ST. CROIX, VIRGIN ISLANDS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. C. B. Van Gaasbeek, Medical Corps, U. S. Navy______ 31</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SUGAR IN URINE.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Lieut. Commander C. W. 0. Bunker, Medical Corps, U. S. Navy, and

Pharmacist's Mate R. L. Thrasher, first class, U. S. Navy------------------

--------------- -------------------- 35</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">CLINICAL NOTES :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">ENDOTHELIOMA.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. L. H. Williams, Medical Corps, U. S. Navy__________ 39</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">GLANDERS IN MAN.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. L. H. Williams and Lieut. R. C. Satterlee, Medical Corps, U.

S. Navy__________________ 41</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">ACUTE APPENDICITIS WITHIN A HERNIA SAC.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. C. B. Van Gaasbeek, Medical Corps, U. S. Navy______ 43</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">CHANCRE OF THE PALMAR SURFACE OF THE HAND.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. (J. G.) J. E. Root, jr., Medical Corps, U. S. Navy____ 44</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">RECURRENT DIFFUSE SCLERODERMA, A CASE OF.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. C. W. Lane, Medical Corps, U. S. Navy_____________ 45</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">ACUTE YELLOW ATROPHY OF LIVER, A CASE OF.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. G. L. McClintock, Medical Corps, U. S. Navy________ 49</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTES AND COMMENTS:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Meeting of the Association of Military Surgeons.-Protection of capital

ships against poison gas.-Thomas Wakley and the Lancet.- Diathermy in

pneumonia.-Prophylactic injection of normal serum against measles.-Lamblial

dysentery treated with carbon tetrachloride.-Endocrine survey____________ 53</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NAVY NURSE CORPS--------------------------------------------- 75</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">INSTRUCTIONS TO MEDICAL OFFICERS:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Shortage in petty-officer ratings in Hospital Corps.-Haemostatic forceps

and surgical needles carried in stock at the medical supply depot-Form N. M. S.

F. (revised) .-Policy of U. S. Employees' Compensation Commission regarding

employees suffering from occupational diseases; now considered compensable and

entitled to treatment.-Hospital accounting.-Examination report, Hospital Corps,

U.S. Navy; Form N. M. S. H. C. 1.-Analysis of the naval hospital ration for

1923 (continental hospitals only).-Reprints of the bureau's circular letters

for office files.-Additional data required on the Form F card in all cases of

injury.-Health records retained in files.-Wampoles hypno-bromic

compound.-Wampoles hypno-bromic compound, analysis requested_____________________

81</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">BOOK NOTICES---------------------------------------------------- 103</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREVENTIVE MEDICINE, STATISTICS:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PNEUMONIA, BRONCHITIS, AND TONSILLITIS SEASON. HOUSING, VENTILATION,

AND CONTACT.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. Commander J. R. Phelps, Medical Corps, U. S. Navy__ 107</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Mass immunity to diseases.-Human intestinal parasites in

Guam.Prevention of venereal disease in England.-Vital statistics_______ 127</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Number 2</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREFACE--------- - - - - --- --- - -- - ---- - -- - -- - ---- --------

---- - - -- -v</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTICE TO SERVICE CONTRIBUTORS --- -- -- -- -- - - ------ - -- - vi</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SPECIAL ARTICLE :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">DETECTION OF THE PSYCHOPATH AND CLASSIFICATION OF NAVAL RECRUITS</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">IN ACCORDANCE WITH THEIR INTELLIGENCE.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. A. W. Stearns, Medical Corps, United States Navy _<span>  </span>149</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">INSULIN TREATMENT OF DIABETES MELLITUS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. Commander W. D. Owens, Medical Corps, United States Navy __________________

_ 170</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOVOCAINE ANESTHESIA.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. Commander G. F. Cottle, Medical Corps, United States Navy

________________ 184</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">OBSERVATIONS CONCERNING YAWS IN HAITI.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. P. W. Wilson, Medical Corps, United States Navy _ _<span>  </span>190</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">RELATION OF THE CLINICAL LABORATORY TO THE MODERN HOSPITAL.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. H. S. Sumerlin, Medical Corps, United States Navy _<span>   </span>196</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">GAS MASK FOR HEAD AND CHEST INJURY CASES.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. F. F. Lane, Medical Corps, United States Navy_____ 200</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">CLINICAL NOTES:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">IMPROVED TECHNIC IN SPINAL PUNCTURE.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. Commander T. W. Raison, Medical Corps, United States Navy____________

205</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">TRAUMATIC HEMATOMA OF SPERMATIC CORD.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. L. H. Williams, Medical Corps, United States Navy__ 206</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">CYSTOSCOPY AND REPORT OF THREE UNUSUAL CASES.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. L. B. Marshall, Medical Corps, United States Navy__ 207</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTES AND COMMENTS:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Value of psychometric tests in the Navy-Need of physiotherapy – Two physicians

of Tortola-The all-purpose canister gas mask<span> 

</span>- Etiology of gout-Bulletin of the National Board of Medical Examiner</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">·-Practical objectives in health work-Alcohol taxation and alcoholism

in Denmark-Revision of the pharmacopaeia-Phlebotomy in the monasteries-New

method of treating syphilis-Operating-room lighting_____ ______ ____ ____ __

___ ____ __ ___ __ ___ ____ 213</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NURSE CORPS:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Nursing in the Philippine Islands-Cooperation with all departments_ 231</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">BOOK NOTICES __ _ 235</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREVENTIVE MEDICINE, STATISTICS:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">ERADICATION OF VERMIN ON BOARD SHIP_______________________ 247</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SPPLEMENTARY REPORT: REVIEW OF LITERATURE RELATING TO PROPHYLAXIS OF

MEASLES.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Dr. T. W. Kemmerer, United States Public Health Service__ 268</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SWIMMING POOLS IN DETROIT---EPIDEMIOLOGICAL CONSIDERATIONS__ 271</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">ADOPTION OF NEW HOUSING ORDINANCE BY THE CITY OF SAN DIEGO, CALIF_274</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">MEDICAL DEPARTMENT ACTIVITIES AT NAVAL TRAINING STATIONS__ 275</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Number 3</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREFACE ------------------------ v</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTICE TO SERVICE CONTRIBUTORS- VI</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SPECIAL ARTICLES:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">AVIATION ACCIDENTS AND METHODS OF PREVENTION.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. J. F. Neuberger, Medical Corps, U. S. Navy__________ 285</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTES AND COMMENTS :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Aviation accidents.-Aeroplane accidents from the British viewpoint.-

The estimation of physical efficiency.-The air ambulance in war.---Gas warfare

in the air.-Ophthalmology in its relation to</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">aviation.-Notes on aviation medicine in France.-Fellowship in the American

College of Surgeons.- Vaccination against smallpox -The instruction of hospital

corpsmen__ 331</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NAVY NURSE CORPS:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTES ON A COURSE FOR INSTRUCTORS OF NURSING-- 363</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREVENTIVE MEDICINE, STATISTICS:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">REMARKS ON THE EPIDEMIOLOGY OF SMALLPOX AND THE PREVENTIVE VALUE OF

VACCINATION WITH COWPOX VIRUS.- MEDICAL OFFICER RECOMMENDS ADOPTION OF A

REGISTER FOR COWPOX VACCINATIONS.- REPORT OF A CASE OF CEREBROSPINAL FEVER AT

THE UNITED STATES NAVAL TRAINING STATION, NEWPORT, R. I.-MEDICAL BULLETIN OF THE

DESTROYER SQUADRONS OF THE BATTLE FLEET.-PROPHYLAXIS OF VENEREAL

DISEASE.-BACILLARY DYSENTERY IN GUAM.-PORTABLE</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">CANVAS SACK STEAM DISINFECTORS AVAILABLE ___________ 395</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Number 4</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREFACE - --- ------ - - --- --- --------- - --- V</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTICE TO SERVICE CONTRIBUTORS__ _________ VI 1</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SPECIAL ARTICLES:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">ELECTROCARDIOGRAPH IN PROGNOSIS VALUE OF.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. Commander W. a. Bloedorn and Lieut. L . J. Roberts, Medical

Corps, United States Navy____ 423</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">ETHYLENE FOR GENERAL ANESTHESIA, USE OF.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander<span>  </span>C. W. Moots,

Medical Corps, United States Naval Reserve Force _ -----.- - - --------

------------- - - - ----------- 429</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">HYDRONEPHROSIS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. Commander R Cuthbertson, Medical Corps, United States Navy

------------ 431</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">UNSUSPECTED SYPHILIS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. Commander W. H. Connor, Medical Corps, United States

Navy_______ 439</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">RISE OF LOCAL ANESTHESIA.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Dr. Charles A. Ingraham ___________ ____________ ___________ 445</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">CLINICAL NOTES:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SARCOMA.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. R. M. Choisser, Medical Corps, United States Navy 451</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">AVULSION OF SCROTUM, LEFT TESTICAL AND SHEATH OF PENIS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. Commander G. F. Cottle, Medical Corps, United States Navy

-------------------------------- 457</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">HYDATIDIFORM MOLE, CASE OF.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. Commander C. C. Kress and Lieut. H. C. Bishop, jr., Medical

Corps, United States Navy____ 460</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTES AND COMMENTS:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Mental tests for recruits-Fish poisons-An eighteenth century country

practice-medical expedition to the South Seas-How to use a refrigerator-

Anaphylactic reaction from typhoid prophylaxis ------------- 463</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NAVY NURSE CORPS:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Relation of the dietetic department to the medical service of a </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">hospital_____________________________________________ 477</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">BOOK NOTICES -------------------------------- 483</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREVENTIVE MEDICINE. STATISTICS:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">The prevention and control of cerebrospinal fever in the British Army as

reviewed in the official history of the war ____________ 493</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Comments relating to health conditions, from the annual report of the

commander of the United States naval detachment in Turkish waters--Toxic effect

of hydrogen sulphide-Eradication of ants from ships of the United Fruit

Co.-Physical examination of food handlers in New York City- Venereal diseases

and prophylaxis in the United States Asiatic Fleet- Typhoid fever report-

Dysentery and the tendency to report ill-defined cases under a dysentery title

- Remarks relating- to the use of nomenclature titles____ _____ 515</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Number 5</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREFACE -- ------- ------------------------------------------------- v</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTICE TO SERVICE CONTRIBUTORS __________________________ _ vi</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SPECIAL ARTICLES : </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">MEDICAL DEPARTMENT OF THE MARINE CORPS, EAST COAST EXPEDITIONARY FORCE,

DURING THE FALL MANEUVERS OF 1923, AN ACCOUNTOF</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. Commander W. Chambers, Medical Corps, U. S. N.____ 531</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PYELOGRAPHY.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander W. S. Pugh, Medical Corps, U.S. N. (ret.)______ 559</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">HYDRONEPHROSIS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. (J. G.) R B. Engle. Medical Corps. U. S. N. 567</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">BICHLORIDE OF MERCURY POISONING WITH CALCIUM SULPHIDE AS A CHEMICAL

ANTIDOTE – A PRELIMINARY REPORT OF THE TREATMENT OF.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. J. M. McCants, Medical Corps, U. S. N. _______________ 572</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">CONSTRUCTION OF VULCANITE PARTIAL DENTURES.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. L. M. Desmond, Dental Corps, U. S. N.---------------- 578</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">CLINICAL NOTES:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">CHRONIC DUODENAL ULCER.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. (J. G.) O. A. Smith, Medical Corps, U. S. N. __________ 581</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">MALIGNANT ENDOCARDITIS FOLLOWING FRACTURE OF THE RIBS, A CARE REPORT.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. (J. G.) B. M. Summers, Medical Corps. U. S. N. ______ 586</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">INCONTINENCE OF URINE.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. (J. G) E. M. Harris, jr., Medical Corps, U. S. N. ______ 591</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">REPORT OF A DEATH OCCURING DURING TREATMENT FOR LEPROSY WITH

CHAULMOOGRA OIL DERIVATIVES.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. F. L. McDaniel, Medical Corps, U. S. N. ______________ 594</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTES AND COMMENTS:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">German hospital ship during the ·world War – Misconduct ruling__ 597</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NAVY NURSE CORPS:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Notes on dietetics taken at Miss Farmer's School of Cookery, Boston, Mass.

----------------- 605</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">INSTRUCTIONS ISSUED BY THE BUREAU OF MEDICINE AND SURGERY:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Patients suffering with tuberculosis or neuropsychiatric diseases and conditions

who are veterans of the Spanish-American War, Boxer Rebellion, and the

Philippine lnsurrection, now under treatment but who are not beneficiaries of

the Veterans' Bureau as veterans of the World War, and who are not at present

members of the regular military and naval establishments--Hospital Corps

Handbook. U.S. Navy, 1923, issue of-Adoption of revised Nomenclature of Diseases

and Injuries, Medical Department. U.S. Navy-Classified expenditures and per

diem cost in naval hospitals (continental), during the quarter ending September

30, 1923--Paragraphs 1280 and 1281, Naval Courts and Boards,

1923-Epidemiological study of influenza, the common cold and other respiratory

disorders, now being carried on by the U. S. Public Health Service, request for

cooperation by medical officers of the Navy-Influenza, the common cold, and

other respiratory disorders - Schedule of wages for civilian employees,

effective .January 1. 1924 -Laboratory courses for nurses of the U.S. Navy -

Enlistment of men not physically qualified - <span> </span>Administration of triple antityphoid

vaccine-Classified expenditures and per item cost in naval hospitals

(continental) during October, 1923 - Form F cards in cases of patients taken up

as from change of diagnosis - Form “ X " - Abstract of enlistments- Addition

of diagnostic title number 1973, “Urticaria," to</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Navy Nomenclature of Diseases and Injuries-Care in handling

concentrated spirit of nitrous ether- <span> </span>Equalization

bill - Modification of present allotment system-Instrument, plastic filling.

Black’s, Nos. 1 to 7, addition to Supply Table, Part II – Assignment of light

duty to hospital patients- Form N. M. S. H. C. S.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">forwarding of, in the case of hospital corpsmen whose records have been

closed fo1· desertion and convicted of absence without leave, or absence over

leave, 01· restored to duty-American Red Cross-Disciplinary regulations

referring to beneficiaries of the U. S. Veterans' Bureau in naval hospitals--Complement

fixation tests for syphilis-Transportation of Insane patients-Closer relation

between medical officers on recruiting duty and the Bureau of Medicine and

Surgery-Memorandum for medical officers on recruiting duty-. Applicants for

appointment in the Navy Nurse Corp, physical examination of--Change in the

Manual of the Medical Department - --- --------------- - ----- -------- ----- -

- - -- __ 617</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">BOOK NOTICES __ --------- - --- --- - ------ --- ---- ----- --- - -----

- - 653</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREVENTIVE MEDICINE STATISTICS:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Resuscitation apparatus - Follow-up treatment of syphilis- Accident statistics

injuries and poisonings-Methods used in the prevention and control of

communicable diseases at the naval training station, Hampton Roads, Va.-

Venereal disease experience of the U.S. S. Detroit during her

"shakedown" cruise—Typhoid fever report-Eradication of vermin : note

from the Marine Barracks, Washington, D. C.- Food poisoning- Improved sanitary quality

of foods now marketed compared with conditions ten years ago, as observed in

Detroit-Physiological effects of high temperatures and high relative

humidity-Supplementary report on tentative bacteriological standards for

swimming pools in Detroit-Correct reporting of cases remaining at the end of

the calendar year 1923 ---------------------- 659</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Number 6</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREFACE ________ v</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTICE TO SERYICE CONTRIBUTORS ----------------------------- vi</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SPECIAL ARTICLES:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">DIAGNOSIS OF EARLY PULMONARY TUBERCULOSIS</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. W. L. Rathbun, Medical Corps, U. S. Naval Reserve Force

____________ 685</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PULMONARY TUBERCULOSIS, EARLY DIAGNOSIS AND TREATMENT OF.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. Commander J. B. Pollard, Medical Corps, U. S. Navy_ 691</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">EXTENSIVE SUPERFICIAL BURNS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. Commander G. W. Shepard, ledical Corps, U. S. Navy_ 697</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SULPHARSPHENAMINE, A REPORT ON ITS USE AT THE MAYO CLINIC, ROCHESTER.

MINN.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. Commander R. Hayden, Medical Corps, U. S. Navy.__ _<span>  </span>702</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">LEPROSY IN THE HAWAIIAN ISLANDS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. J. M. McCants, Medical Corps, U. S. Navy ________ _ 705</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">CLINICAL NOTES:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">KONDOLEON OPERATION AND FILARIASIS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. Commander H. M. Stenhouse. Medical Corps, U. S. Navy

____________ <span> </span>715</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">MAXILLARY SINUSITIS OF DENTAL ORIGIN.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. E. B. Howell, Dental Corps, U. S. Navy_____________ 716</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">REPORT OF A CASE OF LARGE "SOLITARY" TUBERCULOUS ABSCESS OF LIVER.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. L. F. Robinson. Medical Corps, U. S. Naval Reserve Force-------------------------------

719</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">ADVANCED TUBERCULOSIS UNSUCCESSFULLY TREATED BY ARTIFICIAL PNEUMOTHORAX,

COMPLICATED BY PYO-PNEUMOTHORAX AND TREATMENT BY THORACOPLASTY, A CASE OF.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. (Junior Grade) E. W. Gutzmer, Medical Corps, U. S. Navy

---------------------------------- 721</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTES AND COMMENTS :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A correction.-Value and limitations of the Rontgen ray in the diagnosis

of pulmonary affections. - Sulpharsphenamine on board ship.-A note on

interpretation of dental radiographs __________ - 727</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NAVY NURSE CORPS:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">MY FIRST DUTY ABOARD SHIP. THE U. S. S.

"RELIEF"-------------- 739</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">BOOK NOTICES--------------------------------- 751</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREVENTIVE MEDICINE, STATISTICS:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">STUDIES OF SUBMARINE VENTILATION IN TROPICAL WATERS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. Commander R. F. Jones and Lieut. G. H. Mankin, Medical Corps,

U. S. Navy ----------- 759</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">STUDIES BY THE UNIITED STATES PUBLIC HEALTH SERVICE REGARDING CHEMICAL

AND PHYSIOLOGICAL ASPECTS OF INDUSTRIAL FATIGUE__ 795</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">EPIDEMIOLOGICAL REPORT OF AN OUTBREAK OF<span>  </span>BACILLARY DYSENTERY AT THE MARINE BARRACKS,

RIFLE RANGE, SANTO DOMINGO CITY, DOMINICAN REPUBLIC.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. H. B. LaFavre, medical Corps, U. S. Navy____________ 797</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Bacillary dysentery among Marine Corps and Nay personnel serving with

the gendarmerie of Haiti.- Bacillary dysentery in Guam. Needless noise a

detriment to health and efficiency.-Naval training stations, notes

from.-Venereal disease conditions from the U. S. S. "Pittsburgh,"

report on.-Fatal accident attributed to rusty surface of a revolving

shaft-Admissions for injuries and poisonings,</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">January and February, 1924------------------------- 800</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">INDEX<span>  </span>…. I</p>

  

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Note: The colors, contrast and appearance of these illustrations are unlikely to be true to life. They are derived from scanned images that have been enhanced for machine interpretation and have been altered from their originals.

 

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Title: United States Naval Medical Bulletin Vol. 20, Nos. 1-6, 1924

Creator: U.S. Navy. Bureau of Medicine and Surgery

Publisher:

Sponsor:

Contributor:

Date: 1924-01

Language: eng

  

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Table of Contents</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> Number 1</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> PREFACE -------------------------------- - - ------ ------- V</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTICE TO SERVICE CONTRIBUTORS____________________________ VI</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SPECIAL ARTICLES:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Climatic Bubo.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander C. S. Butler, Medical Corps, U. S. Navy______ 1</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTES ON 350 APPENDECTOMIES.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. Commander Lucius W. Johnson, Medical Corps, U. S .. Navy------------------------

-- 7</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">CLINICAL TRIAL OF THE ELLIS TEST FOR TUBERCULOSIS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. D. Ferguson, Medical Corps, U. S. Navy____________ 17</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">CANCER IN ST. CROIX, VIRGIN ISLANDS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. C. B. Van Gaasbeek, Medical Corps, U. S. Navy______ 31</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SUGAR IN URINE.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Lieut. Commander C. W. 0. Bunker, Medical Corps, U. S. Navy, and

Pharmacist's Mate R. L. Thrasher, first class, U. S. Navy------------------

--------------- -------------------- 35</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">CLINICAL NOTES :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">ENDOTHELIOMA.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. L. H. Williams, Medical Corps, U. S. Navy__________ 39</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">GLANDERS IN MAN.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. L. H. Williams and Lieut. R. C. Satterlee, Medical Corps, U.

S. Navy__________________ 41</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">ACUTE APPENDICITIS WITHIN A HERNIA SAC.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. C. B. Van Gaasbeek, Medical Corps, U. S. Navy______ 43</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">CHANCRE OF THE PALMAR SURFACE OF THE HAND.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. (J. G.) J. E. Root, jr., Medical Corps, U. S. Navy____ 44</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">RECURRENT DIFFUSE SCLERODERMA, A CASE OF.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. C. W. Lane, Medical Corps, U. S. Navy_____________ 45</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">ACUTE YELLOW ATROPHY OF LIVER, A CASE OF.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. G. L. McClintock, Medical Corps, U. S. Navy________ 49</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTES AND COMMENTS:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Meeting of the Association of Military Surgeons.-Protection of capital

ships against poison gas.-Thomas Wakley and the Lancet.- Diathermy in

pneumonia.-Prophylactic injection of normal serum against measles.-Lamblial

dysentery treated with carbon tetrachloride.-Endocrine survey____________ 53</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NAVY NURSE CORPS--------------------------------------------- 75</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">INSTRUCTIONS TO MEDICAL OFFICERS:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Shortage in petty-officer ratings in Hospital Corps.-Haemostatic forceps

and surgical needles carried in stock at the medical supply depot-Form N. M. S.

F. (revised) .-Policy of U. S. Employees' Compensation Commission regarding

employees suffering from occupational diseases; now considered compensable and

entitled to treatment.-Hospital accounting.-Examination report, Hospital Corps,

U.S. Navy; Form N. M. S. H. C. 1.-Analysis of the naval hospital ration for

1923 (continental hospitals only).-Reprints of the bureau's circular letters

for office files.-Additional data required on the Form F card in all cases of

injury.-Health records retained in files.-Wampoles hypno-bromic

compound.-Wampoles hypno-bromic compound, analysis requested_____________________

81</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">BOOK NOTICES---------------------------------------------------- 103</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREVENTIVE MEDICINE, STATISTICS:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PNEUMONIA, BRONCHITIS, AND TONSILLITIS SEASON. HOUSING, VENTILATION,

AND CONTACT.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. Commander J. R. Phelps, Medical Corps, U. S. Navy__ 107</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Mass immunity to diseases.-Human intestinal parasites in

Guam.Prevention of venereal disease in England.-Vital statistics_______ 127</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Number 2</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREFACE--------- - - - - --- --- - -- - ---- - -- - -- - ---- --------

---- - - -- -v</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTICE TO SERVICE CONTRIBUTORS --- -- -- -- -- - - ------ - -- - vi</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SPECIAL ARTICLE :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">DETECTION OF THE PSYCHOPATH AND CLASSIFICATION OF NAVAL RECRUITS</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">IN ACCORDANCE WITH THEIR INTELLIGENCE.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. A. W. Stearns, Medical Corps, United States Navy _<span>  </span>149</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">INSULIN TREATMENT OF DIABETES MELLITUS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. Commander W. D. Owens, Medical Corps, United States Navy __________________

_ 170</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOVOCAINE ANESTHESIA.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. Commander G. F. Cottle, Medical Corps, United States Navy

________________ 184</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">OBSERVATIONS CONCERNING YAWS IN HAITI.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. P. W. Wilson, Medical Corps, United States Navy _ _<span>  </span>190</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">RELATION OF THE CLINICAL LABORATORY TO THE MODERN HOSPITAL.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. H. S. Sumerlin, Medical Corps, United States Navy _<span>   </span>196</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">GAS MASK FOR HEAD AND CHEST INJURY CASES.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. F. F. Lane, Medical Corps, United States Navy_____ 200</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">CLINICAL NOTES:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">IMPROVED TECHNIC IN SPINAL PUNCTURE.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. Commander T. W. Raison, Medical Corps, United States Navy____________

205</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">TRAUMATIC HEMATOMA OF SPERMATIC CORD.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. L. H. Williams, Medical Corps, United States Navy__ 206</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">CYSTOSCOPY AND REPORT OF THREE UNUSUAL CASES.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. L. B. Marshall, Medical Corps, United States Navy__ 207</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTES AND COMMENTS:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Value of psychometric tests in the Navy-Need of physiotherapy – Two physicians

of Tortola-The all-purpose canister gas mask<span> 

</span>- Etiology of gout-Bulletin of the National Board of Medical Examiner</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">·-Practical objectives in health work-Alcohol taxation and alcoholism

in Denmark-Revision of the pharmacopaeia-Phlebotomy in the monasteries-New

method of treating syphilis-Operating-room lighting_____ ______ ____ ____ __

___ ____ __ ___ __ ___ ____ 213</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NURSE CORPS:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Nursing in the Philippine Islands-Cooperation with all departments_ 231</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">BOOK NOTICES __ _ 235</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREVENTIVE MEDICINE, STATISTICS:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">ERADICATION OF VERMIN ON BOARD SHIP_______________________ 247</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SPPLEMENTARY REPORT: REVIEW OF LITERATURE RELATING TO PROPHYLAXIS OF

MEASLES.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Dr. T. W. Kemmerer, United States Public Health Service__ 268</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SWIMMING POOLS IN DETROIT---EPIDEMIOLOGICAL CONSIDERATIONS__ 271</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">ADOPTION OF NEW HOUSING ORDINANCE BY THE CITY OF SAN DIEGO, CALIF_274</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">MEDICAL DEPARTMENT ACTIVITIES AT NAVAL TRAINING STATIONS__ 275</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Number 3</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREFACE ------------------------ v</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTICE TO SERVICE CONTRIBUTORS- VI</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SPECIAL ARTICLES:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">AVIATION ACCIDENTS AND METHODS OF PREVENTION.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. J. F. Neuberger, Medical Corps, U. S. Navy__________ 285</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTES AND COMMENTS :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Aviation accidents.-Aeroplane accidents from the British viewpoint.-

The estimation of physical efficiency.-The air ambulance in war.---Gas warfare

in the air.-Ophthalmology in its relation to</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">aviation.-Notes on aviation medicine in France.-Fellowship in the American

College of Surgeons.- Vaccination against smallpox -The instruction of hospital

corpsmen__ 331</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NAVY NURSE CORPS:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTES ON A COURSE FOR INSTRUCTORS OF NURSING-- 363</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREVENTIVE MEDICINE, STATISTICS:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">REMARKS ON THE EPIDEMIOLOGY OF SMALLPOX AND THE PREVENTIVE VALUE OF

VACCINATION WITH COWPOX VIRUS.- MEDICAL OFFICER RECOMMENDS ADOPTION OF A

REGISTER FOR COWPOX VACCINATIONS.- REPORT OF A CASE OF CEREBROSPINAL FEVER AT

THE UNITED STATES NAVAL TRAINING STATION, NEWPORT, R. I.-MEDICAL BULLETIN OF THE

DESTROYER SQUADRONS OF THE BATTLE FLEET.-PROPHYLAXIS OF VENEREAL

DISEASE.-BACILLARY DYSENTERY IN GUAM.-PORTABLE</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">CANVAS SACK STEAM DISINFECTORS AVAILABLE ___________ 395</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Number 4</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREFACE - --- ------ - - --- --- --------- - --- V</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTICE TO SERVICE CONTRIBUTORS__ _________ VI 1</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SPECIAL ARTICLES:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">ELECTROCARDIOGRAPH IN PROGNOSIS VALUE OF.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. Commander W. a. Bloedorn and Lieut. L . J. Roberts, Medical

Corps, United States Navy____ 423</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">ETHYLENE FOR GENERAL ANESTHESIA, USE OF.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander<span>  </span>C. W. Moots,

Medical Corps, United States Naval Reserve Force _ -----.- - - --------

------------- - - - ----------- 429</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">HYDRONEPHROSIS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. Commander R Cuthbertson, Medical Corps, United States Navy

------------ 431</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">UNSUSPECTED SYPHILIS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. Commander W. H. Connor, Medical Corps, United States

Navy_______ 439</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">RISE OF LOCAL ANESTHESIA.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Dr. Charles A. Ingraham ___________ ____________ ___________ 445</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">CLINICAL NOTES:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SARCOMA.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. R. M. Choisser, Medical Corps, United States Navy 451</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">AVULSION OF SCROTUM, LEFT TESTICAL AND SHEATH OF PENIS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. Commander G. F. Cottle, Medical Corps, United States Navy

-------------------------------- 457</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">HYDATIDIFORM MOLE, CASE OF.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. Commander C. C. Kress and Lieut. H. C. Bishop, jr., Medical

Corps, United States Navy____ 460</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTES AND COMMENTS:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Mental tests for recruits-Fish poisons-An eighteenth century country

practice-medical expedition to the South Seas-How to use a refrigerator-

Anaphylactic reaction from typhoid prophylaxis ------------- 463</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NAVY NURSE CORPS:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Relation of the dietetic department to the medical service of a </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">hospital_____________________________________________ 477</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">BOOK NOTICES -------------------------------- 483</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREVENTIVE MEDICINE. STATISTICS:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">The prevention and control of cerebrospinal fever in the British Army as

reviewed in the official history of the war ____________ 493</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Comments relating to health conditions, from the annual report of the

commander of the United States naval detachment in Turkish waters--Toxic effect

of hydrogen sulphide-Eradication of ants from ships of the United Fruit

Co.-Physical examination of food handlers in New York City- Venereal diseases

and prophylaxis in the United States Asiatic Fleet- Typhoid fever report-

Dysentery and the tendency to report ill-defined cases under a dysentery title

- Remarks relating- to the use of nomenclature titles____ _____ 515</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Number 5</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREFACE -- ------- ------------------------------------------------- v</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTICE TO SERVICE CONTRIBUTORS __________________________ _ vi</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SPECIAL ARTICLES : </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">MEDICAL DEPARTMENT OF THE MARINE CORPS, EAST COAST EXPEDITIONARY FORCE,

DURING THE FALL MANEUVERS OF 1923, AN ACCOUNTOF</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. Commander W. Chambers, Medical Corps, U. S. N.____ 531</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PYELOGRAPHY.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander W. S. Pugh, Medical Corps, U.S. N. (ret.)______ 559</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">HYDRONEPHROSIS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. (J. G.) R B. Engle. Medical Corps. U. S. N. 567</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">BICHLORIDE OF MERCURY POISONING WITH CALCIUM SULPHIDE AS A CHEMICAL

ANTIDOTE – A PRELIMINARY REPORT OF THE TREATMENT OF.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. J. M. McCants, Medical Corps, U. S. N. _______________ 572</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">CONSTRUCTION OF VULCANITE PARTIAL DENTURES.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. L. M. Desmond, Dental Corps, U. S. N.---------------- 578</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">CLINICAL NOTES:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">CHRONIC DUODENAL ULCER.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. (J. G.) O. A. Smith, Medical Corps, U. S. N. __________ 581</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">MALIGNANT ENDOCARDITIS FOLLOWING FRACTURE OF THE RIBS, A CARE REPORT.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. (J. G.) B. M. Summers, Medical Corps. U. S. N. ______ 586</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">INCONTINENCE OF URINE.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. (J. G) E. M. Harris, jr., Medical Corps, U. S. N. ______ 591</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">REPORT OF A DEATH OCCURING DURING TREATMENT FOR LEPROSY WITH

CHAULMOOGRA OIL DERIVATIVES.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. F. L. McDaniel, Medical Corps, U. S. N. ______________ 594</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTES AND COMMENTS:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">German hospital ship during the ·world War – Misconduct ruling__ 597</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NAVY NURSE CORPS:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Notes on dietetics taken at Miss Farmer's School of Cookery, Boston, Mass.

----------------- 605</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">INSTRUCTIONS ISSUED BY THE BUREAU OF MEDICINE AND SURGERY:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Patients suffering with tuberculosis or neuropsychiatric diseases and conditions

who are veterans of the Spanish-American War, Boxer Rebellion, and the

Philippine lnsurrection, now under treatment but who are not beneficiaries of

the Veterans' Bureau as veterans of the World War, and who are not at present

members of the regular military and naval establishments--Hospital Corps

Handbook. U.S. Navy, 1923, issue of-Adoption of revised Nomenclature of Diseases

and Injuries, Medical Department. U.S. Navy-Classified expenditures and per

diem cost in naval hospitals (continental), during the quarter ending September

30, 1923--Paragraphs 1280 and 1281, Naval Courts and Boards,

1923-Epidemiological study of influenza, the common cold and other respiratory

disorders, now being carried on by the U. S. Public Health Service, request for

cooperation by medical officers of the Navy-Influenza, the common cold, and

other respiratory disorders - Schedule of wages for civilian employees,

effective .January 1. 1924 -Laboratory courses for nurses of the U.S. Navy -

Enlistment of men not physically qualified - <span> </span>Administration of triple antityphoid

vaccine-Classified expenditures and per item cost in naval hospitals

(continental) during October, 1923 - Form F cards in cases of patients taken up

as from change of diagnosis - Form “ X " - Abstract of enlistments- Addition

of diagnostic title number 1973, “Urticaria," to</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Navy Nomenclature of Diseases and Injuries-Care in handling

concentrated spirit of nitrous ether- <span> </span>Equalization

bill - Modification of present allotment system-Instrument, plastic filling.

Black’s, Nos. 1 to 7, addition to Supply Table, Part II – Assignment of light

duty to hospital patients- Form N. M. S. H. C. S.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">forwarding of, in the case of hospital corpsmen whose records have been

closed fo1· desertion and convicted of absence without leave, or absence over

leave, 01· restored to duty-American Red Cross-Disciplinary regulations

referring to beneficiaries of the U. S. Veterans' Bureau in naval hospitals--Complement

fixation tests for syphilis-Transportation of Insane patients-Closer relation

between medical officers on recruiting duty and the Bureau of Medicine and

Surgery-Memorandum for medical officers on recruiting duty-. Applicants for

appointment in the Navy Nurse Corp, physical examination of--Change in the

Manual of the Medical Department - --- --------------- - ----- -------- ----- -

- - -- __ 617</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">BOOK NOTICES __ --------- - --- --- - ------ --- ---- ----- --- - -----

- - 653</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREVENTIVE MEDICINE STATISTICS:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Resuscitation apparatus - Follow-up treatment of syphilis- Accident statistics

injuries and poisonings-Methods used in the prevention and control of

communicable diseases at the naval training station, Hampton Roads, Va.-

Venereal disease experience of the U.S. S. Detroit during her

"shakedown" cruise—Typhoid fever report-Eradication of vermin : note

from the Marine Barracks, Washington, D. C.- Food poisoning- Improved sanitary quality

of foods now marketed compared with conditions ten years ago, as observed in

Detroit-Physiological effects of high temperatures and high relative

humidity-Supplementary report on tentative bacteriological standards for

swimming pools in Detroit-Correct reporting of cases remaining at the end of

the calendar year 1923 ---------------------- 659</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Number 6</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREFACE ________ v</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTICE TO SERYICE CONTRIBUTORS ----------------------------- vi</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SPECIAL ARTICLES:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">DIAGNOSIS OF EARLY PULMONARY TUBERCULOSIS</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. W. L. Rathbun, Medical Corps, U. S. Naval Reserve Force

____________ 685</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PULMONARY TUBERCULOSIS, EARLY DIAGNOSIS AND TREATMENT OF.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. Commander J. B. Pollard, Medical Corps, U. S. Navy_ 691</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">EXTENSIVE SUPERFICIAL BURNS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. Commander G. W. Shepard, ledical Corps, U. S. Navy_ 697</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SULPHARSPHENAMINE, A REPORT ON ITS USE AT THE MAYO CLINIC, ROCHESTER.

MINN.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. Commander R. Hayden, Medical Corps, U. S. Navy.__ _<span>  </span>702</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">LEPROSY IN THE HAWAIIAN ISLANDS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. J. M. McCants, Medical Corps, U. S. Navy ________ _ 705</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">CLINICAL NOTES:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">KONDOLEON OPERATION AND FILARIASIS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. Commander H. M. Stenhouse. Medical Corps, U. S. Navy

____________ <span> </span>715</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">MAXILLARY SINUSITIS OF DENTAL ORIGIN.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. E. B. Howell, Dental Corps, U. S. Navy_____________ 716</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">REPORT OF A CASE OF LARGE "SOLITARY" TUBERCULOUS ABSCESS OF LIVER.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. L. F. Robinson. Medical Corps, U. S. Naval Reserve Force-------------------------------

719</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">ADVANCED TUBERCULOSIS UNSUCCESSFULLY TREATED BY ARTIFICIAL PNEUMOTHORAX,

COMPLICATED BY PYO-PNEUMOTHORAX AND TREATMENT BY THORACOPLASTY, A CASE OF.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. (Junior Grade) E. W. Gutzmer, Medical Corps, U. S. Navy

---------------------------------- 721</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTES AND COMMENTS :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A correction.-Value and limitations of the Rontgen ray in the diagnosis

of pulmonary affections. - Sulpharsphenamine on board ship.-A note on

interpretation of dental radiographs __________ - 727</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NAVY NURSE CORPS:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">MY FIRST DUTY ABOARD SHIP. THE U. S. S.

"RELIEF"-------------- 739</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">BOOK NOTICES--------------------------------- 751</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREVENTIVE MEDICINE, STATISTICS:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">STUDIES OF SUBMARINE VENTILATION IN TROPICAL WATERS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. Commander R. F. Jones and Lieut. G. H. Mankin, Medical Corps,

U. S. Navy ----------- 759</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">STUDIES BY THE UNIITED STATES PUBLIC HEALTH SERVICE REGARDING CHEMICAL

AND PHYSIOLOGICAL ASPECTS OF INDUSTRIAL FATIGUE__ 795</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">EPIDEMIOLOGICAL REPORT OF AN OUTBREAK OF<span>  </span>BACILLARY DYSENTERY AT THE MARINE BARRACKS,

RIFLE RANGE, SANTO DOMINGO CITY, DOMINICAN REPUBLIC.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. H. B. LaFavre, medical Corps, U. S. Navy____________ 797</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Bacillary dysentery among Marine Corps and Nay personnel serving with

the gendarmerie of Haiti.- Bacillary dysentery in Guam. Needless noise a

detriment to health and efficiency.-Naval training stations, notes

from.-Venereal disease conditions from the U. S. S. "Pittsburgh,"

report on.-Fatal accident attributed to rusty surface of a revolving

shaft-Admissions for injuries and poisonings,</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">January and February, 1924------------------------- 800</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">INDEX<span>  </span>…. I</p>

  

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Chakra is a concept referring to wheel-like vortices which, according to traditional Indian medicine, are believed to exist in the surface of the etheric double of man. The Chakras are said to be "force centers" or whorls of energy permeating, from a point on the physical body, the layers of the subtle bodies in an ever-increasing fan-shaped formation (the fans make the shape of a love heart). Rotating vortices of subtle matter, they are considered the focal points for the reception and transmission of energies. Seven major chakras or energy centers (also understood as wheels of light) are generally believed to exist, located within the subtle body. Practitioners of Hinduism and New Age Spirituality believe the chakras interact with the body's ductless endocrine glands and lymphatic system by feeding in good bio-energies and disposing of unwanted bio-energies.

 

Much of the original information on Chakras comes from the "Upanishads", which are difficult to date because they are believed to have been passed down orally for approximately a thousand years before being written down for the first time between 1200–900 BCE.

 

en.wikipedia.org/wiki/Chakra

 

Facebook retrofuturs group.

There is growing interest in the possible health threat posed by endocrine-disrupting chemicals (EDCs), which are substances in our environment, food, and consumer products that interfere with hormone biosynthesis, metabolism, or action resulting in a deviation from normal homeostatic control or reproduction.

 

In this first Scientific Statement of The Endocrine Society , we present the evidence that endocrine disruptors have effects on male and female reproduction, breast development and cancer, prostate cancer, neuroendocrinology, thyroid, metabolism and obesity, and cardiovascular endocrinology.

 

Results from animal models, human clinical observations, and epidemiological studies converge to implicate EDCs as a significant concern to public health. The mechanisms of EDCs involve divergent pathways including (but not limited to) estrogenic, antiandrogenic, thyroid, peroxisome proliferator-activated receptor γ, retinoid, and actions through other nuclear receptors; steroidogenic enzymes; neurotransmitter receptors and systems; and many other pathways that are highly conserved in wildlife and humans, and which can be modeled in laboratory in vitro and in vivo models. Furthermore, EDCs represent a broad class of molecules such as organochlorinated pesticides and industrial chemicals, plastics and plasticizers, fuels, and many other chemicals that are present in the environment or are in widespread use.

 

We make a number of recommendations to increase understanding of effects of EDCs, including enhancing increased basic and clinical research, invoking the precautionary principle, and advocating involvement of individual and scientific society stakeholders in communicating and implementing changes in public policy and awareness.

 

Accepted: April 17, 2009 - First Published Online: July 01, 2013.

 

Sources and more information

* Flickr album DES and EDCs Research.

* EDC-2: The Endocrine Society’s Second Scientific Statement on Endocrine-Disrupting Chemicals, DOI: 10.1210/er.2015-1010, November 06, 2015.

* Executive Summary to EDC-2: The Endocrine Society’s Second Scientific Statement on Endocrine-Disrupting Chemicals, DOI: 10.1210/er.2015-1093, September 28, 2015.

* Endocrine-Disrupting Chemicals: An Endocrine Society Scientific Statement, NCBI PMCID: PMC2726844, doi: 10.1210/er.2009-0002, June 2009.

 

Auditory hallucinations are the perception of sound without outside stimulus. Auditory hallucinations can be divided into two categories: elementary and complex. Elementary hallucinations are the perception of sounds such as hissing, whistling, an extended tone, and more. In many cases, tinnitus is an elementary auditory hallucination. However, some people who experience certain types of tinnitus, especially pulsatile tinnitus, are actually hearing the blood rushing through vessels near the ear. Because the auditory stimulus is present in this situation, it does not qualify as a hallucination.

Complex hallucinations are those of voices, music, or other sounds which may or may not be clear, may be familiar or completely unfamiliar, and friendly or aggressive, among other possibilities. Hallucinations of one or more talking voices are particularly associated with psychotic disorders such as schizophrenia, and hold special significance in diagnosing these conditions. However, many people not suffering from diagnosable mental illness may sometimes hear voices as well. One important example to consider when forming a differential diagnosis for a patient with paracusia is lateral temporal lobe epilepsy. Despite the tendency to associate hearing voices, or otherwise hallucinating, and psychosis with schizophrenia or other psychiatric illnesses, it is crucial to take into consideration that even if a person does exhibit psychotic features, they do not necessarily suffer from a psychiatric disorder on its own. Disorders such as Wilson's disease, various endocrine diseases, numerous metabolic disturbances, multiple sclerosis, systemic lupus erythematosis, porphyria, sarcoidosis, and many others can present with psychosis.

Musical hallucinations are also relatively common in terms of complex auditory hallucinations and may be the result of a wide range of causes ranging from hearing-loss (such as in musical ear syndrome, the auditory version of Charles Bonnet syndrome), lateral temporal lobe epilepsy, arteriovenous malformation, stroke, lesion, abscess, or tumor.

The Hearing Voices Movement is a support and advocacy group for people who hallucinate voices, but do not otherwise show signs of mental illness or impairment.

High caffeine consumption has been linked to an increase in the likelihood of experiencing auditory hallucinations. A study conducted by the La Trobe University School of Psychological Sciences revealed that as few as five cups of coffee a day could trigger the phenomenon.

Command hallucinations

Command hallucinations are hallucinations in the form of commands; they can be auditory or inside of the persons mind and / or consciousness. The contents of the hallucinations can range from the innocuous to commands to cause harm to the self or others. Command hallucinations are often associated with schizophrenia. People experiencing command hallucinations may or may not comply with the hallucinated commands, depending on circumstances. Compliance is more common for non-violent commands.

Command hallucinations are sometimes used in defense of a crime, often homicides. It is essentially a voice one hears and it tells them what to do. "Sometimes they are quite benign directives such as "Stand up." or "Shut the door." Whether it is a command for something simple or something that is a threat, it is still considered a "command hallucination." Some helpful questions that can assist one in figuring out if they may be suffering from this includes: "What are the voices telling you to do?","When did your voices first start telling you to do things?, "Do you recognize the person who is telling you to harm yourself (others)?", "Do you think you can resist doing what the voices are telling you to do?".

Fish, any of approximately 34,000 species of vertebrate animals (phylum Chordata) found in the fresh and salt waters of the world. Living species range from the primitive jawless lampreys and hagfishes through the cartilaginous sharks, skates, and rays to the abundant and diverse bony fishes. Most fish species are cold-blooded; however, one species, the opah (Lampris guttatus), is warm-blooded.

 

The term fish is applied to a variety of vertebrates of several evolutionary lines. It describes a life-form rather than a taxonomic group. As members of the phylum Chordata, fish share certain features with other vertebrates. These features are gill slits at some point in the life cycle, a notochord, or skeletal supporting rod, a dorsal hollow nerve cord, and a tail. Living fishes represent some five classes, which are as distinct from one another as are the four classes of familiar air-breathing animals—amphibians, reptiles, birds, and mammals. For example, the jawless fishes (Agnatha) have gills in pouches and lack limb girdles. Extant agnathans are the lampreys and the hagfishes. As the name implies, the skeletons of fishes of the class Chondrichthyes (from chondr, “cartilage,” and ichthyes, “fish”) are made entirely of cartilage. Modern fish of this class lack a swim bladder, and their scales and teeth are made up of the same placoid material. Sharks, skates, and rays are examples of cartilaginous fishes. The bony fishes are by far the largest class. Examples range from the tiny seahorse to the 450-kg (1,000-pound) blue marlin, from the flattened soles and flounders to the boxy puffers and ocean sunfishes. Unlike the scales of the cartilaginous fishes, those of bony fishes, when present, grow throughout life and are made up of thin overlapping plates of bone. Bony fishes also have an operculum that covers the gill slits.

 

The study of fishes, the science of ichthyology, is of broad importance. Fishes are of interest to humans for many reasons, the most important being their relationship with and dependence on the environment. A more obvious reason for interest in fishes is their role as a moderate but important part of the world’s food supply. This resource, once thought unlimited, is now realized to be finite and in delicate balance with the biological, chemical, and physical factors of the aquatic environment. Overfishing, pollution, and alteration of the environment are the chief enemies of proper fisheries management, both in fresh waters and in the ocean. (For a detailed discussion of the technology and economics of fisheries, see commercial fishing.) Another practical reason for studying fishes is their use in disease control. As predators on mosquito larvae, they help curb malaria and other mosquito-borne diseases.

 

Fishes are valuable laboratory animals in many aspects of medical and biological research. For example, the readiness of many fishes to acclimate to captivity has allowed biologists to study behaviour, physiology, and even ecology under relatively natural conditions. Fishes have been especially important in the study of animal behaviour, where research on fishes has provided a broad base for the understanding of the more flexible behaviour of the higher vertebrates. The zebra fish is used as a model in studies of gene expression.

 

There are aesthetic and recreational reasons for an interest in fishes. Millions of people keep live fishes in home aquariums for the simple pleasure of observing the beauty and behaviour of animals otherwise unfamiliar to them. Aquarium fishes provide a personal challenge to many aquarists, allowing them to test their ability to keep a small section of the natural environment in their homes. Sportfishing is another way of enjoying the natural environment, also indulged in by millions of people every year. Interest in aquarium fishes and sportfishing supports multimillion-dollar industries throughout the world.

 

Fishes have been in existence for more than 450 million years, during which time they have evolved repeatedly to fit into almost every conceivable type of aquatic habitat. In a sense, land vertebrates are simply highly modified fishes: when fishes colonized the land habitat, they became tetrapod (four-legged) land vertebrates. The popular conception of a fish as a slippery, streamlined aquatic animal that possesses fins and breathes by gills applies to many fishes, but far more fishes deviate from that conception than conform to it. For example, the body is elongate in many forms and greatly shortened in others; the body is flattened in some (principally in bottom-dwelling fishes) and laterally compressed in many others; the fins may be elaborately extended, forming intricate shapes, or they may be reduced or even lost; and the positions of the mouth, eyes, nostrils, and gill openings vary widely. Air breathers have appeared in several evolutionary lines.

 

Many fishes are cryptically coloured and shaped, closely matching their respective environments; others are among the most brilliantly coloured of all organisms, with a wide range of hues, often of striking intensity, on a single individual. The brilliance of pigments may be enhanced by the surface structure of the fish, so that it almost seems to glow. A number of unrelated fishes have actual light-producing organs. Many fishes are able to alter their coloration—some for the purpose of camouflage, others for the enhancement of behavioral signals.

 

Fishes range in adult length from less than 10 mm (0.4 inch) to more than 20 metres (60 feet) and in weight from about 1.5 grams (less than 0.06 ounce) to many thousands of kilograms. Some live in shallow thermal springs at temperatures slightly above 42 °C (100 °F), others in cold Arctic seas a few degrees below 0 °C (32 °F) or in cold deep waters more than 4,000 metres (13,100 feet) beneath the ocean surface. The structural and, especially, the physiological adaptations for life at such extremes are relatively poorly known and provide the scientifically curious with great incentive for study.

 

Almost all natural bodies of water bear fish life, the exceptions being very hot thermal ponds and extremely salt-alkaline lakes, such as the Dead Sea in Asia and the Great Salt Lake in North America. The present distribution of fishes is a result of the geological history and development of Earth as well as the ability of fishes to undergo evolutionary change and to adapt to the available habitats. Fishes may be seen to be distributed according to habitat and according to geographical area. Major habitat differences are marine and freshwater. For the most part, the fishes in a marine habitat differ from those in a freshwater habitat, even in adjacent areas, but some, such as the salmon, migrate from one to the other. The freshwater habitats may be seen to be of many kinds. Fishes found in mountain torrents, Arctic lakes, tropical lakes, temperate streams, and tropical rivers will all differ from each other, both in obvious gross structure and in physiological attributes. Even in closely adjacent habitats where, for example, a tropical mountain torrent enters a lowland stream, the fish fauna will differ. The marine habitats can be divided into deep ocean floors (benthic), mid-water oceanic (bathypelagic), surface oceanic (pelagic), rocky coast, sandy coast, muddy shores, bays, estuaries, and others. Also, for example, rocky coastal shores in tropical and temperate regions will have different fish faunas, even when such habitats occur along the same coastline.

 

Although much is known about the present geographical distribution of fishes, far less is known about how that distribution came about. Many parts of the fish fauna of the fresh waters of North America and Eurasia are related and undoubtedly have a common origin. The faunas of Africa and South America are related, extremely old, and probably an expression of the drifting apart of the two continents. The fauna of southern Asia is related to that of Central Asia, and some of it appears to have entered Africa. The extremely large shore-fish faunas of the Indian and tropical Pacific oceans comprise a related complex, but the tropical shore fauna of the Atlantic, although containing Indo-Pacific components, is relatively limited and probably younger. The Arctic and Antarctic marine faunas are quite different from each other. The shore fauna of the North Pacific is quite distinct, and that of the North Atlantic more limited and probably younger. Pelagic oceanic fishes, especially those in deep waters, are similar the world over, showing little geographical isolation in terms of family groups. The deep oceanic habitat is very much the same throughout the world, but species differences do exist, showing geographical areas determined by oceanic currents and water masses.

 

All aspects of the life of a fish are closely correlated with adaptation to the total environment, physical, chemical, and biological. In studies, all the interdependent aspects of fish, such as behaviour, locomotion, reproduction, and physical and physiological characteristics, must be taken into account.

 

Correlated with their adaptation to an extremely wide variety of habitats is the extremely wide variety of life cycles that fishes display. The great majority hatch from relatively small eggs a few days to several weeks or more after the eggs are scattered in the water. Newly hatched young are still partially undeveloped and are called larvae until body structures such as fins, skeleton, and some organs are fully formed. Larval life is often very short, usually less than a few weeks, but it can be very long, some lampreys continuing as larvae for at least five years. Young and larval fishes, before reaching sexual maturity, must grow considerably, and their small size and other factors often dictate that they live in a habitat different than that of the adults. For example, most tropical marine shore fishes have pelagic larvae. Larval food also is different, and larval fishes often live in shallow waters, where they may be less exposed to predators.

 

After a fish reaches adult size, the length of its life is subject to many factors, such as innate rates of aging, predation pressure, and the nature of the local climate. The longevity of a species in the protected environment of an aquarium may have nothing to do with how long members of that species live in the wild. Many small fishes live only one to three years at the most. In some species, however, individuals may live as long as 10 or 20 or even 100 years.

 

Fish behaviour is a complicated and varied subject. As in almost all animals with a central nervous system, the nature of a response of an individual fish to stimuli from its environment depends upon the inherited characteristics of its nervous system, on what it has learned from past experience, and on the nature of the stimuli. Compared with the variety of human responses, however, that of a fish is stereotyped, not subject to much modification by “thought” or learning, and investigators must guard against anthropomorphic interpretations of fish behaviour.

 

Fishes perceive the world around them by the usual senses of sight, smell, hearing, touch, and taste and by special lateral line water-current detectors. In the few fishes that generate electric fields, a process that might best be called electrolocation aids in perception. One or another of these senses often is emphasized at the expense of others, depending upon the fish’s other adaptations. In fishes with large eyes, the sense of smell may be reduced; others, with small eyes, hunt and feed primarily by smell (such as some eels).

 

Specialized behaviour is primarily concerned with the three most important activities in the fish’s life: feeding, reproduction, and escape from enemies. Schooling behaviour of sardines on the high seas, for instance, is largely a protective device to avoid enemies, but it is also associated with and modified by their breeding and feeding requirements. Predatory fishes are often solitary, lying in wait to dart suddenly after their prey, a kind of locomotion impossible for beaked parrot fishes, which feed on coral, swimming in small groups from one coral head to the next. In addition, some predatory fishes that inhabit pelagic environments, such as tunas, often school.

 

Sleep in fishes, all of which lack true eyelids, consists of a seemingly listless state in which the fish maintains its balance but moves slowly. If attacked or disturbed, most can dart away. A few kinds of fishes lie on the bottom to sleep. Most catfishes, some loaches, and some eels and electric fishes are strictly nocturnal, being active and hunting for food during the night and retiring during the day to holes, thick vegetation, or other protective parts of the environment.

 

Communication between members of a species or between members of two or more species often is extremely important, especially in breeding behaviour (see below Reproduction). The mode of communication may be visual, as between the small so-called cleaner fish and a large fish of a very different species. The larger fish often allows the cleaner to enter its mouth to remove gill parasites. The cleaner is recognized by its distinctive colour and actions and therefore is not eaten, even if the larger fish is normally a predator. Communication is often chemical, signals being sent by specific chemicals called pheromones.

 

Many fishes have a streamlined body and swim freely in open water. Fish locomotion is closely correlated with habitat and ecological niche (the general position of the animal to its environment).

 

Many fishes in both marine and fresh waters swim at the surface and have mouths adapted to feed best (and sometimes only) at the surface. Often such fishes are long and slender, able to dart at surface insects or at other surface fishes and in turn to dart away from predators; needlefishes, halfbeaks, and topminnows (such as killifish and mosquito fish) are good examples. Oceanic flying fishes escape their predators by gathering speed above the water surface, with the lower lobe of the tail providing thrust in the water. They then glide hundreds of yards on enlarged, winglike pectoral and pelvic fins. South American freshwater flying fishes escape their enemies by jumping and propelling their strongly keeled bodies out of the water.

 

So-called mid-water swimmers, the most common type of fish, are of many kinds and live in many habitats. The powerful fusiform tunas and the trouts, for example, are adapted for strong, fast swimming, the tunas to capture prey speedily in the open ocean and the trouts to cope with the swift currents of streams and rivers. The trout body form is well adapted to many habitats. Fishes that live in relatively quiet waters such as bays or lake shores or slow rivers usually are not strong, fast swimmers but are capable of short, quick bursts of speed to escape a predator. Many of these fishes have their sides flattened, examples being the sunfish and the freshwater angelfish of aquarists. Fish associated with the bottom or substrate usually are slow swimmers. Open-water plankton-feeding fishes almost always remain fusiform and are capable of rapid, strong movement (for example, sardines and herrings of the open ocean and also many small minnows of streams and lakes).

 

Bottom-living fishes are of many kinds and have undergone many types of modification of their body shape and swimming habits. Rays, which evolved from strong-swimming mid-water sharks, usually stay close to the bottom and move by undulating their large pectoral fins. Flounders live in a similar habitat and move over the bottom by undulating the entire body. Many bottom fishes dart from place to place, resting on the bottom between movements, a motion common in gobies. One goby relative, the mudskipper, has taken to living at the edge of pools along the shore of muddy mangrove swamps. It escapes its enemies by flipping rapidly over the mud, out of the water. Some catfishes, synbranchid eels, the so-called climbing perch, and a few other fishes venture out over damp ground to find more promising waters than those that they left. They move by wriggling their bodies, sometimes using strong pectoral fins; most have accessory air-breathing organs. Many bottom-dwelling fishes live in mud holes or rocky crevices. Marine eels and gobies commonly are found in such habitats and for the most part venture far beyond their cavelike homes. Some bottom dwellers, such as the clingfishes (Gobiesocidae), have developed powerful adhesive disks that enable them to remain in place on the substrate in areas such as rocky coasts, where the action of the waves is great.

 

The methods of reproduction in fishes are varied, but most fishes lay a large number of small eggs, fertilized and scattered outside of the body. The eggs of pelagic fishes usually remain suspended in the open water. Many shore and freshwater fishes lay eggs on the bottom or among plants. Some have adhesive eggs. The mortality of the young and especially of the eggs is very high, and often only a few individuals grow to maturity out of hundreds, thousands, and in some cases millions of eggs laid.

 

Males produce sperm, usually as a milky white substance called milt, in two (sometimes one) testes within the body cavity. In bony fishes a sperm duct leads from each testis to a urogenital opening behind the vent or anus. In sharks and rays and in cyclostomes the duct leads to a cloaca. Sometimes the pelvic fins are modified to help transmit the milt to the eggs at the female’s vent or on the substrate where the female has placed them. Sometimes accessory organs are used to fertilize females internally—for example, the claspers of many sharks and rays.

 

In the females the eggs are formed in two ovaries (sometimes only one) and pass through the ovaries to the urogenital opening and to the outside. In some fishes the eggs are fertilized internally but are shed before development takes place. Members of about a dozen families each of bony fishes (teleosts) and sharks bear live young. Many skates and rays also bear live young. In some bony fishes the eggs simply develop within the female, the young emerging when the eggs hatch (ovoviviparous). Others develop within the ovary and are nourished by ovarian tissues after hatching (viviparous). There are also other methods utilized by fishes to nourish young within the female. In all live-bearers the young are born at a relatively large size and are few in number. In one family of primarily marine fishes, the surfperches from the Pacific coast of North America, Japan, and Korea, the males of at least one species are born sexually mature, although they are not fully grown.

 

Some fishes are hermaphroditic—an individual producing both sperm and eggs, usually at different stages of its life. Self-fertilization, however, is probably rare.

 

Successful reproduction and, in many cases, defense of the eggs and the young are assured by rather stereotypical but often elaborate courtship and parental behaviour, either by the male or the female or both. Some fishes prepare nests by hollowing out depressions in the sand bottom (cichlids, for example), build nests with plant materials and sticky threads excreted by the kidneys (sticklebacks), or blow a cluster of mucus-covered bubbles at the water surface (gouramis). The eggs are laid in these structures. Some varieties of cichlids and catfishes incubate eggs in their mouths.

 

Some fishes, such as salmon, undergo long migrations from the ocean and up large rivers to spawn in the gravel beds where they themselves hatched (anadromous fishes). Some, such as the freshwater eels (family Anguillidae), live and grow to maturity in fresh water and migrate to the sea to spawn (catadromous fishes). Other fishes undertake shorter migrations from lakes into streams, within the ocean, or enter spawning habitats that they do not ordinarily occupy in other ways.

 

The basic structure and function of the fish body are similar to those of all other vertebrates. The usual four types of tissues are present: surface or epithelial, connective (bone, cartilage, and fibrous tissues, as well as their derivative, blood), nerve, and muscle tissues. In addition, the fish’s organs and organ systems parallel those of other vertebrates.

 

The typical fish body is streamlined and spindle-shaped, with an anterior head, a gill apparatus, and a heart, the latter lying in the midline just below the gill chamber. The body cavity, containing the vital organs, is situated behind the head in the lower anterior part of the body. The anus usually marks the posterior termination of the body cavity and most often occurs just in front of the base of the anal fin. The spinal cord and vertebral column continue from the posterior part of the head to the base of the tail fin, passing dorsal to the body cavity and through the caudal (tail) region behind the body cavity. Most of the body is of muscular tissue, a high proportion of which is necessitated by swimming. In the course of evolution this basic body plan has been modified repeatedly into the many varieties of fish shapes that exist today.

 

The skeleton forms an integral part of the fish’s locomotion system, as well as serving to protect vital parts. The internal skeleton consists of the skull bones (except for the roofing bones of the head, which are really part of the external skeleton), the vertebral column, and the fin supports (fin rays). The fin supports are derived from the external skeleton but will be treated here because of their close functional relationship to the internal skeleton. The internal skeleton of cyclostomes, sharks, and rays is of cartilage; that of many fossil groups and some primitive living fishes is mostly of cartilage but may include some bone. In place of the vertebral column, the earliest vertebrates had a fully developed notochord, a flexible stiff rod of viscous cells surrounded by a strong fibrous sheath. During the evolution of modern fishes the rod was replaced in part by cartilage and then by ossified cartilage. Sharks and rays retain a cartilaginous vertebral column; bony fishes have spool-shaped vertebrae that in the more primitive living forms only partially replace the notochord. The skull, including the gill arches and jaws of bony fishes, is fully, or at least partially, ossified. That of sharks and rays remains cartilaginous, at times partially replaced by calcium deposits but never by true bone.

 

The supportive elements of the fins (basal or radial bones or both) have changed greatly during fish evolution. Some of these changes are described in the section below (Evolution and paleontology). Most fishes possess a single dorsal fin on the midline of the back. Many have two and a few have three dorsal fins. The other fins are the single tail and anal fins and paired pelvic and pectoral fins. A small fin, the adipose fin, with hairlike fin rays, occurs in many of the relatively primitive teleosts (such as trout) on the back near the base of the caudal fin.

 

The skin of a fish must serve many functions. It aids in maintaining the osmotic balance, provides physical protection for the body, is the site of coloration, contains sensory receptors, and, in some fishes, functions in respiration. Mucous glands, which aid in maintaining the water balance and offer protection from bacteria, are extremely numerous in fish skin, especially in cyclostomes and teleosts. Since mucous glands are present in the modern lampreys, it is reasonable to assume that they were present in primitive fishes, such as the ancient Silurian and Devonian agnathans. Protection from abrasion and predation is another function of the fish skin, and dermal (skin) bone arose early in fish evolution in response to this need. It is thought that bone first evolved in skin and only later invaded the cartilaginous areas of the fish’s body, to provide additional support and protection. There is some argument as to which came first, cartilage or bone, and fossil evidence does not settle the question. In any event, dermal bone has played an important part in fish evolution and has different characteristics in different groups of fishes. Several groups are characterized at least in part by the kind of bony scales they possess.

 

Scales have played an important part in the evolution of fishes. Primitive fishes usually had thick bony plates or thick scales in several layers of bone, enamel, and related substances. Modern teleost fishes have scales of bone, which, while still protective, allow much more freedom of motion in the body. A few modern teleosts (some catfishes, sticklebacks, and others) have secondarily acquired bony plates in the skin. Modern and early sharks possessed placoid scales, a relatively primitive type of scale with a toothlike structure, consisting of an outside layer of enamel-like substance (vitrodentine), an inner layer of dentine, and a pulp cavity containing nerves and blood vessels. Primitive bony fishes had thick scales of either the ganoid or the cosmoid type. Cosmoid scales have a hard, enamel-like outer layer, an inner layer of cosmine (a form of dentine), and then a layer of vascular bone (isopedine). In ganoid scales the hard outer layer is different chemically and is called ganoin. Under this is a cosminelike layer and then a vascular bony layer. The thin, translucent bony scales of modern fishes, called cycloid and ctenoid (the latter distinguished by serrations at the edges), lack enameloid and dentine layers.

 

Skin has several other functions in fishes. It is well supplied with nerve endings and presumably receives tactile, thermal, and pain stimuli. Skin is also well supplied with blood vessels. Some fishes breathe in part through the skin, by the exchange of oxygen and carbon dioxide between the surrounding water and numerous small blood vessels near the skin surface.

 

Skin serves as protection through the control of coloration. Fishes exhibit an almost limitless range of colours. The colours often blend closely with the surroundings, effectively hiding the animal. Many fishes use bright colours for territorial advertisement or as recognition marks for other members of their own species, or sometimes for members of other species. Many fishes can change their colour to a greater or lesser degree, by movement of pigment within the pigment cells (chromatophores). Black pigment cells (melanophores), of almost universal occurrence in fishes, are often juxtaposed with other pigment cells. When placed beneath iridocytes or leucophores (bearing the silvery or white pigment guanine), melanophores produce structural colours of blue and green. These colours are often extremely intense, because they are formed by refraction of light through the needlelike crystals of guanine. The blue and green refracted colours are often relatively pure, lacking the red and yellow rays, which have been absorbed by the black pigment (melanin) of the melanophores. Yellow, orange, and red colours are produced by erythrophores, cells containing the appropriate carotenoid pigments. Other colours are produced by combinations of melanophores, erythrophores, and iridocytes.

 

The major portion of the body of most fishes consists of muscles. Most of the mass is trunk musculature, the fin muscles usually being relatively small. The caudal fin is usually the most powerful fin, being moved by the trunk musculature. The body musculature is usually arranged in rows of chevron-shaped segments on each side. Contractions of these segments, each attached to adjacent vertebrae and vertebral processes, bends the body on the vertebral joint, producing successive undulations of the body, passing from the head to the tail, and producing driving strokes of the tail. It is the latter that provides the strong forward movement for most fishes.

 

The digestive system, in a functional sense, starts at the mouth, with the teeth used to capture prey or collect plant foods. Mouth shape and tooth structure vary greatly in fishes, depending on the kind of food normally eaten. Most fishes are predacious, feeding on small invertebrates or other fishes and have simple conical teeth on the jaws, on at least some of the bones of the roof of the mouth, and on special gill arch structures just in front of the esophagus. The latter are throat teeth. Most predacious fishes swallow their prey whole, and the teeth are used for grasping and holding prey, for orienting prey to be swallowed (head first) and for working the prey toward the esophagus. There are a variety of tooth types in fishes. Some fishes, such as sharks and piranhas, have cutting teeth for biting chunks out of their victims. A shark’s tooth, although superficially like that of a piranha, appears in many respects to be a modified scale, while that of the piranha is like that of other bony fishes, consisting of dentine and enamel. Parrot fishes have beaklike mouths with short incisor-like teeth for breaking off coral and have heavy pavementlike throat teeth for crushing the coral. Some catfishes have small brushlike teeth, arranged in rows on the jaws, for scraping plant and animal growth from rocks. Many fishes (such as the Cyprinidae or minnows) have no jaw teeth at all but have very strong throat teeth.

 

Some fishes gather planktonic food by straining it from their gill cavities with numerous elongate stiff rods (gill rakers) anchored by one end to the gill bars. The food collected on these rods is passed to the throat, where it is swallowed. Most fishes have only short gill rakers that help keep food particles from escaping out the mouth cavity into the gill chamber.

 

Once reaching the throat, food enters a short, often greatly distensible esophagus, a simple tube with a muscular wall leading into a stomach. The stomach varies greatly in fishes, depending upon the diet. In most predacious fishes it is a simple straight or curved tube or pouch with a muscular wall and a glandular lining. Food is largely digested there and leaves the stomach in liquid form.

 

Between the stomach and the intestine, ducts enter the digestive tube from the liver and pancreas. The liver is a large, clearly defined organ. The pancreas may be embedded in it, diffused through it, or broken into small parts spread along some of the intestine. The junction between the stomach and the intestine is marked by a muscular valve. Pyloric ceca (blind sacs) occur in some fishes at this junction and have a digestive or absorptive function or both.

 

The intestine itself is quite variable in length, depending upon the fish’s diet. It is short in predacious forms, sometimes no longer than the body cavity, but long in herbivorous forms, being coiled and several times longer than the entire length of the fish in some species of South American catfishes. The intestine is primarily an organ for absorbing nutrients into the bloodstream. The larger its internal surface, the greater its absorptive efficiency, and a spiral valve is one method of increasing its absorption surface.

 

Sharks, rays, chimaeras, lungfishes, surviving chondrosteans, holosteans, and even a few of the more primitive teleosts have a spiral valve or at least traces of it in the intestine. Most modern teleosts have increased the area of the intestinal walls by having numerous folds and villi (fingerlike projections) somewhat like those in humans. Undigested substances are passed to the exterior through the anus in most teleost fishes. In lungfishes, sharks, and rays, it is first passed through the cloaca, a common cavity receiving the intestinal opening and the ducts from the urogenital system.

 

Oxygen and carbon dioxide dissolve in water, and most fishes exchange dissolved oxygen and carbon dioxide in water by means of the gills. The gills lie behind and to the side of the mouth cavity and consist of fleshy filaments supported by the gill arches and filled with blood vessels, which give gills a bright red colour. Water taken in continuously through the mouth passes backward between the gill bars and over the gill filaments, where the exchange of gases takes place. The gills are protected by a gill cover in teleosts and many other fishes but by flaps of skin in sharks, rays, and some of the older fossil fish groups. The blood capillaries in the gill filaments are close to the gill surface to take up oxygen from the water and to give up excess carbon dioxide to the water.

 

Most modern fishes have a hydrostatic (ballast) organ, called the swim bladder, that lies in the body cavity just below the kidney and above the stomach and intestine. It originated as a diverticulum of the digestive canal. In advanced teleosts, especially the acanthopterygians, the bladder has lost its connection with the digestive tract, a condition called physoclistic. The connection has been retained (physostomous) by many relatively primitive teleosts. In several unrelated lines of fishes, the bladder has become specialized as a lung or, at least, as a highly vascularized accessory breathing organ. Some fishes with such accessory organs are obligate air breathers and will drown if denied access to the surface, even in well-oxygenated water. Fishes with a hydrostatic form of swim bladder can control their depth by regulating the amount of gas in the bladder. The gas, mostly oxygen, is secreted into the bladder by special glands, rendering the fish more buoyant; the gas is absorbed into the bloodstream by another special organ, reducing the overall buoyancy and allowing the fish to sink. Some deep-sea fishes may have oils, rather than gas, in the bladder. Other deep-sea and some bottom-living forms have much-reduced swim bladders or have lost the organ entirely.

 

The swim bladder of fishes follows the same developmental pattern as the lungs of land vertebrates. There is no doubt that the two structures have the same historical origin in primitive fishes. More or less intermediate forms still survive among the more primitive types of fishes, such as the lungfishes Lepidosiren and Protopterus.

 

The circulatory, or blood vascular, system consists of the heart, the arteries, the capillaries, and the veins. It is in the capillaries that the interchange of oxygen, carbon dioxide, nutrients, and other substances such as hormones and waste products takes place. The capillaries lead to the veins, which return the venous blood with its waste products to the heart, kidneys, and gills. There are two kinds of capillary beds: those in the gills and those in the rest of the body. The heart, a folded continuous muscular tube with three or four saclike enlargements, undergoes rhythmic contractions and receives venous blood in a sinus venosus. It passes the blood to an auricle and then into a thick muscular pump, the ventricle. From the ventricle the blood goes to a bulbous structure at the base of a ventral aorta just below the gills. The blood passes to the afferent (receiving) arteries of the gill arches and then to the gill capillaries. There waste gases are given off to the environment, and oxygen is absorbed. The oxygenated blood enters efferent (exuant) arteries of the gill arches and then flows into the dorsal aorta. From there blood is distributed to the tissues and organs of the body. One-way valves prevent backflow. The circulation of fishes thus differs from that of the reptiles, birds, and mammals in that oxygenated blood is not returned to the heart prior to distribution to the other parts of the body.

 

The primary excretory organ in fishes, as in other vertebrates, is the kidney. In fishes some excretion also takes place in the digestive tract, skin, and especially the gills (where ammonia is given off). Compared with land vertebrates, fishes have a special problem in maintaining their internal environment at a constant concentration of water and dissolved substances, such as salts. Proper balance of the internal environment (homeostasis) of a fish is in a great part maintained by the excretory system, especially the kidney.

 

The kidney, gills, and skin play an important role in maintaining a fish’s internal environment and checking the effects of osmosis. Marine fishes live in an environment in which the water around them has a greater concentration of salts than they can have inside their body and still maintain life. Freshwater fishes, on the other hand, live in water with a much lower concentration of salts than they require inside their bodies. Osmosis tends to promote the loss of water from the body of a marine fish and absorption of water by that of a freshwater fish. Mucus in the skin tends to slow the process but is not a sufficient barrier to prevent the movement of fluids through the permeable skin. When solutions on two sides of a permeable membrane have different concentrations of dissolved substances, water will pass through the membrane into the more concentrated solution, while the dissolved chemicals move into the area of lower concentration (diffusion).

 

The kidney of freshwater fishes is often larger in relation to body weight than that of marine fishes. In both groups the kidney excretes wastes from the body, but the kidney of freshwater fishes also excretes large amounts of water, counteracting the water absorbed through the skin. Freshwater fishes tend to lose salt to the environment and must replace it. They get some salt from their food, but the gills and skin inside the mouth actively absorb salt from water passed through the mouth. This absorption is performed by special cells capable of moving salts against the diffusion gradient. Freshwater fishes drink very little water and take in little water with their food.

 

Marine fishes must conserve water, and therefore their kidneys excrete little water. To maintain their water balance, marine fishes drink large quantities of seawater, retaining most of the water and excreting the salt. Most nitrogenous waste in marine fishes appears to be secreted by the gills as ammonia. Marine fishes can excrete salt by clusters of special cells (chloride cells) in the gills.

 

There are several teleosts—for example, the salmon—that travel between fresh water and seawater and must adjust to the reversal of osmotic gradients. They adjust their physiological processes by spending time (often surprisingly little time) in the intermediate brackish environment.

 

Marine hagfishes, sharks, and rays have osmotic concentrations in their blood about equal to that of seawater and so do not have to drink water nor perform much physiological work to maintain their osmotic balance. In sharks and rays the osmotic concentration is kept high by retention of urea in the blood. Freshwater sharks have a lowered concentration of urea in the blood.

 

Endocrine glands secrete their products into the bloodstream and body tissues and, along with the central nervous system, control and regulate many kinds of body functions. Cyclostomes have a well-developed endocrine system, and presumably it was well developed in the early Agnatha, ancestral to modern fishes. Although the endocrine system in fishes is similar to that of higher vertebrates, there are numerous differences in detail. The pituitary, the thyroid, the suprarenals, the adrenals, the pancreatic islets, the sex glands (ovaries and testes), the inner wall of the intestine, and the bodies of the ultimobranchial gland make up the endocrine system in fishes. There are some others whose function is not well understood. These organs regulate sexual activity and reproduction, growth, osmotic pressure, general metabolic activities such as the storage of fat and the utilization of foodstuffs, blood pressure, and certain aspects of skin colour. Many of these activities are also controlled in part by the central nervous system, which works with the endocrine system in maintaining the life of a fish. Some parts of the endocrine system are developmentally, and undoubtedly evolutionarily, derived from the nervous system.

 

As in all vertebrates, the nervous system of fishes is the primary mechanism coordinating body activities, as well as integrating these activities in the appropriate manner with stimuli from the environment. The central nervous system, consisting of the brain and spinal cord, is the primary integrating mechanism. The peripheral nervous system, consisting of nerves that connect the brain and spinal cord to various body organs, carries sensory information from special receptor organs such as the eyes, internal ears, nares (sense of smell), taste glands, and others to the integrating centres of the brain and spinal cord. The peripheral nervous system also carries information via different nerve cells from the integrating centres of the brain and spinal cord. This coded information is carried to the various organs and body systems, such as the skeletal muscular system, for appropriate action in response to the original external or internal stimulus. Another branch of the nervous system, the autonomic nervous system, helps to coordinate the activities of many glands and organs and is itself closely connected to the integrating centres of the brain.

 

The brain of the fish is divided into several anatomical and functional parts, all closely interconnected but each serving as the primary centre of integrating particular kinds of responses and activities. Several of these centres or parts are primarily associated with one type of sensory perception, such as sight, hearing, or smell (olfaction).

 

The sense of smell is important in almost all fishes. Certain eels with tiny eyes depend mostly on smell for location of food. The olfactory, or nasal, organ of fishes is located on the dorsal surface of the snout. The lining of the nasal organ has special sensory cells that perceive chemicals dissolved in the water, such as substances from food material, and send sensory information to the brain by way of the first cranial nerve. Odour also serves as an alarm system. Many fishes, especially various species of freshwater minnows, react with alarm to a chemical released from the skin of an injured member of their own species.

 

Many fishes have a well-developed sense of taste, and tiny pitlike taste buds or organs are located not only within their mouth cavities but also over their heads and parts of their body. Catfishes, which often have poor vision, have barbels (“whiskers”) that serve as supplementary taste organs, those around the mouth being actively used to search out food on the bottom. Some species of naturally blind cave fishes are especially well supplied with taste buds, which often cover most of their body surface.

 

Sight is extremely important in most fishes. The eye of a fish is basically like that of all other vertebrates, but the eyes of fishes are extremely varied in structure and adaptation. In general, fishes living in dark and dim water habitats have large eyes, unless they have specialized in some compensatory way so that another sense (such as smell) is dominant, in which case the eyes will often be reduced. Fishes living in brightly lighted shallow waters often will have relatively small but efficient eyes. Cyclostomes have somewhat less elaborate eyes than other fishes, with skin stretched over the eyeball perhaps making their vision somewhat less effective. Most fishes have a spherical lens and accommodate their vision to far or near subjects by moving the lens within the eyeball. A few sharks accommodate by changing the shape of the lens, as in land vertebrates. Those fishes that are heavily dependent upon the eyes have especially strong muscles for accommodation. Most fishes see well, despite the restrictions imposed by frequent turbidity of the water and by light refraction.

 

Fossil evidence suggests that colour vision evolved in fishes more than 300 million years ago, but not all living fishes have retained this ability. Experimental evidence indicates that many shallow-water fishes, if not all, have colour vision and see some colours especially well, but some bottom-dwelling shore fishes live in areas where the water is sufficiently deep to filter out most if not all colours, and these fishes apparently never see colours. When tested in shallow water, they apparently are unable to respond to colour differences.

 

Sound perception and balance are intimately associated senses in a fish. The organs of hearing are entirely internal, located within the skull, on each side of the brain and somewhat behind the eyes. Sound waves, especially those of low frequencies, travel readily through water and impinge directly upon the bones and fluids of the head and body, to be transmitted to the hearing organs. Fishes readily respond to sound; for example, a trout conditioned to escape by the approach of fishermen will take flight upon perceiving footsteps on a stream bank even if it cannot see a fisherman. Compared with humans, however, the range of sound frequencies heard by fishes is greatly restricted. Many fishes communicate with each other by producing sounds in their swim bladders, in their throats by rasping their teeth, and in other ways.

 

A fish or other vertebrate seldom has to rely on a single type of sensory information to determine the nature of the environment around it. A catfish uses taste and touch when examining a food object with its oral barbels. Like most other animals, fishes have many touch receptors over their body surface. Pain and temperature receptors also are present in fishes and presumably produce the same kind of information to a fish as to humans. Fishes react in a negative fashion to stimuli that would be painful to human beings, suggesting that they feel a sensation of pain.

 

An important sensory system in fishes that is absent in other vertebrates (except some amphibians) is the lateral line system. This consists of a series of heavily innervated small canals located in the skin and bone around the eyes, along the lower jaw, over the head, and down the mid-side of the body, where it is associated with the scales. Intermittently along these canals are located tiny sensory organs (pit organs) that apparently detect changes in pressure. The system allows a fish to sense changes in water currents and pressure, thereby helping the fish to orient itself to the various changes that occur in the physical environment.

  

No Brainer

 

The impact of chemicals on children’s brain development: a cause for concern and a need for action

 

Science has shown that many thousands of people have been exposed to now mostly banned chemicals such as lead and PCBs at high enough levels to have had their brain development negatively affected. This report finds that there are other chemicals which are still in routine use in our homes where there is evidence of similar developmental neurotoxic (DNT) properties, and also identifies huge gaps in our knowledge of the impacts of other chemicals on brain development. It also points out the unpleasant reality that we are constantly exposed to a cocktail of chemicals, something which is still largely ignored by chemical safety laws.

 

In spite of the lessons of the past, regulators are continuing to only regulate after harm is caused, instead of acting to effectively protect the most precious of things; children’s developing brains.

 

In June 2007 CHEM Trust wrote the briefing Chemicals Compromising Our Children, which highlighted growing concerns about the impacts of chemicals on brain development in children. Almost 10 years later, CHEM Trust has revisited the issue with this report, which includes contributions from two of the most eminent scientists in this area, Professor Barbara Demeneix (Laboratory of Evolution of Endocrine Regulations, CNRS, Paris) and Professor Philippe Grandjean (Department of Environmental Medicine, University of Southern Denmark, Denmark & Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, USA), who also peer reviewed the report.

 

Our brain and its development

 

Our brains are astoundingly complex, made up of over 85 billion neurons, which have grown, developed and interconnected during our lives. The brain is the organ that takes the longest to develop, with initial stages of cell division, creation of neurons and their migration taking place from the first hours after fertilisation and throughout the foetus’ time in the womb. However, brain development does not stop at birth – it’s not until our twenties that neurons are fully developed with their myelin coats.

 

Throughout this complex developmental process a range of signalling chemicals and other processes operate in order to control what happens. The thyroid hormone system is intimately involved in brain development and function, yet it is well established that this system can be disrupted – for example by a lack of iodine (essential to make thyroid hormone) or by certain chemicals. If developmental processes are disrupted, this most often creates permanent problems.

 

The complexity of brain development and function means that deficits can be very subtle – small reductions in IQ, disabilities that exist with a broad spectrum of seriousness such as autism, or in some cases conditions which do not have fully agreed diagnostic criteria.

 

Disruption of brain development by chemicals

 

We are all exposed to hundreds of man-made chemicals in our daily life, coming from everyday products including food, furniture, packaging and clothes. Many of these chemicals will have no negative effects on us, but it is now well established that some are able to disrupt normal development of the brain. Chemicals with long established DNT properties such as lead, PCBs and methylmercury, have been joined by others where DNT effects have been identified more recently, and which are being used in everyday products. There are also rising concerns about chemicals that are very similar to chemicals that have had their use restricted, but which we continue to use as there isn’t sufficient information about their toxic effects. We know even less about thousands of other chemicals in routine use, which have had no testing for DNT properties.

 

Chemical exposures are so ubiquitous that experts have recognized that babies are born “pre-polluted”. Scientific paediatric and gynaecology & obstetrics societies have consistently warned about chronic health implications from both acute and chronic exposure to chemicals such as pesticides and endocrine disruptors.

 

The report identifies evidence of DNT properties for the following chemicals:

 

- Bisphenol A (BPA)

a chemical that was used to make baby bottles, is currently being phased out of till receipts (in the EU), but is still used in the making of food can linings and many polycarbonate plastics. There are also concerns about closely related chemicals that are not restricted, including Bisphenol S.

- Brominated Flame Retardants (BFRs)

a group of chemicals added to furniture, electronics and building materials. The evidence for neurodevelopmental effects is strongest for the PBDE (polybrominated diphenyl ether) group of BFRs, which are already banned or nearly banned in the EU, though they are still in furniture in our homes, and in dust. However, other BFRs are now being found in dust and human blood serum, with concerns that these BFRs might have similar effects.

- Phthalates

a group of chemicals used as plasticisers in PVC and in other products. Some chemicals in this group are now banned in the EU, but many others are still in use.

- Per- and poly-fluorocarbons (PFCs)

used as non-stick coatings or breathable coatings, are a large group of chemicals, a few of which are in the process of being restricted by the EU. There is evidence that some PFCs can disrupt the action of the thyroid hormone. PFCs are very persistent in the environment, and many of them can accumulate in our bodies – they are routinely found in blood.

- Perchlorate

a contaminant of food, related to the use of certain fertilisers and hypochlorite bleach, and is known to disrupt the thyroid hormone system.

 

Are we protected?

 

The EU has the most sophisticated regulations in the world for controlling chemical use. However, there are a number of key flaws in this system:

 

- There is often inadequate safety information about individual chemicals, including a lack of information about neurodevelopmental effects.

- The processes to ban chemicals are too slow, and the restrictions created often have big loopholes as a result of industry lobbying.

- Chemicals are addressed one at a time, so one chemical may have its use restricted, but closely related chemicals remain in use.

- We are always exposed to multiple chemicals, but regulations almost always assume we are only exposed to one at a time, even though numerous scientists have shown that chemical effects can add together in our bodies.

 

Policy recommendations

 

It is clear that our children are not currently being protected from chemicals that can disrupt brain development. We have identified a range of policy measures that could improve the situation, including:

 

- Acting faster to ban chemicals of concern, including addressing groups of similar substances, not just those where we have the most information.

- Ensuring that any safety testing of chemicals includes evaluation of DNT effects.

- Ensuring better identification and regulation of neurodevelopmental toxic chemicals.

- Ensuring that all uses of chemicals are properly regulated; for example there is a lack of effective regulation of chemicals in food packaging including paper, card, inks, glues and coatings.

- The UK and Ireland should remove the requirement for an open flame test for furniture. This test is not required in the rest of the EU, and leads to increased use of flame retardant chemicals.

 

Finally, it is important to note that EU regulations have already controlled a number of chemicals of concern, and that EU laws provide a tool to address these problems. We therefore think it is vital for the UK Government to work to stay aligned with EU chemicals laws, whatever the eventual outcome of the UK’s Brexit process.

 

Though full protection will only come from proper regulation of chemicals, the report also includes a chapter with tips for reducing your and your family’s exposures in daily life.

 

Sources and More Information

- Download the full report, No Brainer The impact of chemicals on children’s brain development: a cause for concern and a need for action, chemtrust, 2017.

- IT’S A NO BRAINER! Action needed to stop children being exposed to chemicals that harm their brain development!, chemtrust, MARCH 7, 2017.

Amidst the growing burden of diabetes worldwide, diabetes care leader Novo Nordisk, the University of Santo Tomas (UST) Hospital Section of Endocrine, Diabetes and Metabolism, the UST College of Education, and the Philippine Society for Endocrinology, Diabetes and Metabolism (PSEDM) conducted screening activities, patient education and simulation of diabetes complications at the UST campus as part of the country’s observance of World Diabetes Day (WDD). The event themed “Reducing Risk for Diabetes, Reducing Risk for Complications” was attended by more than 150 people where the culminating activity was the formation of the World Diabetes Day Blue Circle.

 

Latest data from the International Diabetes Federation (IDF) reveal that 415 Million people worldwide have diabetes. The IDF estimates that this figure will increase to 642 million by 2040.1

 

About 3.27 million people in the Philippines have diabetes, affecting one in 16 of the country’s adult population. An estimated 1.74 million Filipinos remain undiagnosed and are therefore untreated, putting them at risk for complications such as heart attack, blindness, kidney failure and loss of limbs. In 2014, over 50,000 deaths in the country were related to diabetes.

 

“The number of Filipinos with diabetes continues to rise. If not controlled, diabetes causes life-threatening complications. As such, we need to increase awareness on diabetes prevention, early diagnosis and optimal treatment,” said Dr. Sjoberg Kho, Chief, Section of Endocrinology, Diabetes and Metabolism, University of Santo Tomas Hospital (USTH).

 

“Patient education and awareness is crucial in the prevention and optimal management of diabetes. An informed patient has a much better chance of preventing the serious complications of the disease,” said Associate Professor Cristina Sagum, Program Chair, UST College of Education, Department of Nutrition and Dietetics.

 

“Diabetes management requires a multi-disciplinary team consisting of endocrinologists, nurses, diabetes educators, podiatrists, nutritionists-dietitians and, most importantly, patients. Patient self-management is vital in optimal diabetes management,” said Associate Professor Zenaida Velasco, UST Department of Nutrition and Dietetics; and former Board of Director, Philippine Association of Diabetes Educators (PADE).

 

“The number of people living with diabetes continues to grow. Of the 415 million people with the condition, almost half do not even know they have it, putting them at risk of developing serious complications such as heart attacks, blindness, kidney failure

and loss of limbs. Novo Nordisk is committed to change diabetes and we are honored to work with our partners in celebrating World Diabetes Day in the Philippines,” said Mr. Jeppe B. Theisen, General Manager, Novo Nordisk Pharmaceuticals Philippines, Inc (NNPPI).

 

“A healthy lifestyle, which includes proper diet and regular exercise, combined with optimal treatment compliance is the key to reducing the risk for serious, life-threatening complications of diabetes. Self-management as well as helping educate family members who may also be at risk is a vital role of patients,” said PSEDM President Dr. Bien Matawaran.

 

Held at the UST College of Education quadrangle on November 10, 2015, the World Diabetes Day activity was organized by Novo Nordisk Philippines in partnership with the USTH Section of Endocrinology, Diabetes and Metabolism, the UST College of Education and the PSEDM. Activities included screening tests for fasting blood sugar (FBS), lectures on healthy eating and reducing risk of complications, and interactive simulation booths designed to let people “experience” the serious complications of diabetes such as hypoglycemia, blindness, amputation, dialysis and peripheral neuropathy (loss or tingling of sensation in hands or feet).

 

In the Blindness Booth, a person wears a blindfold and walks around the booth for three minutes. In the Amputation Booth, a person uses crutches to walk around the booth for five minutes. In the Hypo Simulation Booth, a person wears a 3D simulator headgear and watches a 3-minute video on how hypoglycemia feels. In the Nutrition Counselling Booth, a person receives healthy eating advice from a nutritionist-dietician. In the Dialysis Simulation Booth, a person wears a 3D simulator headgear and watches a 5-minute video on how undergoing dialysis feels. The Neuropathy booth, while patient is wearing thick gloves, they will touch certain textures to experience limited touch sensation.

 

For the culminating activity of the World Diabetes Day activity at UST, members of the Ugnayan Diabetes Club, UST faculty members and students, USTH healthcare professionals, and Novo Nordisk Philippines employees formed a Blue Circle in the UST Football Field. The Blue Circle is the international ‘unite for diabetes’ symbol.

Fish, any of approximately 34,000 species of vertebrate animals (phylum Chordata) found in the fresh and salt waters of the world. Living species range from the primitive jawless lampreys and hagfishes through the cartilaginous sharks, skates, and rays to the abundant and diverse bony fishes. Most fish species are cold-blooded; however, one species, the opah (Lampris guttatus), is warm-blooded.

 

The term fish is applied to a variety of vertebrates of several evolutionary lines. It describes a life-form rather than a taxonomic group. As members of the phylum Chordata, fish share certain features with other vertebrates. These features are gill slits at some point in the life cycle, a notochord, or skeletal supporting rod, a dorsal hollow nerve cord, and a tail. Living fishes represent some five classes, which are as distinct from one another as are the four classes of familiar air-breathing animals—amphibians, reptiles, birds, and mammals. For example, the jawless fishes (Agnatha) have gills in pouches and lack limb girdles. Extant agnathans are the lampreys and the hagfishes. As the name implies, the skeletons of fishes of the class Chondrichthyes (from chondr, “cartilage,” and ichthyes, “fish”) are made entirely of cartilage. Modern fish of this class lack a swim bladder, and their scales and teeth are made up of the same placoid material. Sharks, skates, and rays are examples of cartilaginous fishes. The bony fishes are by far the largest class. Examples range from the tiny seahorse to the 450-kg (1,000-pound) blue marlin, from the flattened soles and flounders to the boxy puffers and ocean sunfishes. Unlike the scales of the cartilaginous fishes, those of bony fishes, when present, grow throughout life and are made up of thin overlapping plates of bone. Bony fishes also have an operculum that covers the gill slits.

 

The study of fishes, the science of ichthyology, is of broad importance. Fishes are of interest to humans for many reasons, the most important being their relationship with and dependence on the environment. A more obvious reason for interest in fishes is their role as a moderate but important part of the world’s food supply. This resource, once thought unlimited, is now realized to be finite and in delicate balance with the biological, chemical, and physical factors of the aquatic environment. Overfishing, pollution, and alteration of the environment are the chief enemies of proper fisheries management, both in fresh waters and in the ocean. (For a detailed discussion of the technology and economics of fisheries, see commercial fishing.) Another practical reason for studying fishes is their use in disease control. As predators on mosquito larvae, they help curb malaria and other mosquito-borne diseases.

 

Fishes are valuable laboratory animals in many aspects of medical and biological research. For example, the readiness of many fishes to acclimate to captivity has allowed biologists to study behaviour, physiology, and even ecology under relatively natural conditions. Fishes have been especially important in the study of animal behaviour, where research on fishes has provided a broad base for the understanding of the more flexible behaviour of the higher vertebrates. The zebra fish is used as a model in studies of gene expression.

 

There are aesthetic and recreational reasons for an interest in fishes. Millions of people keep live fishes in home aquariums for the simple pleasure of observing the beauty and behaviour of animals otherwise unfamiliar to them. Aquarium fishes provide a personal challenge to many aquarists, allowing them to test their ability to keep a small section of the natural environment in their homes. Sportfishing is another way of enjoying the natural environment, also indulged in by millions of people every year. Interest in aquarium fishes and sportfishing supports multimillion-dollar industries throughout the world.

 

Fishes have been in existence for more than 450 million years, during which time they have evolved repeatedly to fit into almost every conceivable type of aquatic habitat. In a sense, land vertebrates are simply highly modified fishes: when fishes colonized the land habitat, they became tetrapod (four-legged) land vertebrates. The popular conception of a fish as a slippery, streamlined aquatic animal that possesses fins and breathes by gills applies to many fishes, but far more fishes deviate from that conception than conform to it. For example, the body is elongate in many forms and greatly shortened in others; the body is flattened in some (principally in bottom-dwelling fishes) and laterally compressed in many others; the fins may be elaborately extended, forming intricate shapes, or they may be reduced or even lost; and the positions of the mouth, eyes, nostrils, and gill openings vary widely. Air breathers have appeared in several evolutionary lines.

 

Many fishes are cryptically coloured and shaped, closely matching their respective environments; others are among the most brilliantly coloured of all organisms, with a wide range of hues, often of striking intensity, on a single individual. The brilliance of pigments may be enhanced by the surface structure of the fish, so that it almost seems to glow. A number of unrelated fishes have actual light-producing organs. Many fishes are able to alter their coloration—some for the purpose of camouflage, others for the enhancement of behavioral signals.

 

Fishes range in adult length from less than 10 mm (0.4 inch) to more than 20 metres (60 feet) and in weight from about 1.5 grams (less than 0.06 ounce) to many thousands of kilograms. Some live in shallow thermal springs at temperatures slightly above 42 °C (100 °F), others in cold Arctic seas a few degrees below 0 °C (32 °F) or in cold deep waters more than 4,000 metres (13,100 feet) beneath the ocean surface. The structural and, especially, the physiological adaptations for life at such extremes are relatively poorly known and provide the scientifically curious with great incentive for study.

 

Almost all natural bodies of water bear fish life, the exceptions being very hot thermal ponds and extremely salt-alkaline lakes, such as the Dead Sea in Asia and the Great Salt Lake in North America. The present distribution of fishes is a result of the geological history and development of Earth as well as the ability of fishes to undergo evolutionary change and to adapt to the available habitats. Fishes may be seen to be distributed according to habitat and according to geographical area. Major habitat differences are marine and freshwater. For the most part, the fishes in a marine habitat differ from those in a freshwater habitat, even in adjacent areas, but some, such as the salmon, migrate from one to the other. The freshwater habitats may be seen to be of many kinds. Fishes found in mountain torrents, Arctic lakes, tropical lakes, temperate streams, and tropical rivers will all differ from each other, both in obvious gross structure and in physiological attributes. Even in closely adjacent habitats where, for example, a tropical mountain torrent enters a lowland stream, the fish fauna will differ. The marine habitats can be divided into deep ocean floors (benthic), mid-water oceanic (bathypelagic), surface oceanic (pelagic), rocky coast, sandy coast, muddy shores, bays, estuaries, and others. Also, for example, rocky coastal shores in tropical and temperate regions will have different fish faunas, even when such habitats occur along the same coastline.

 

Although much is known about the present geographical distribution of fishes, far less is known about how that distribution came about. Many parts of the fish fauna of the fresh waters of North America and Eurasia are related and undoubtedly have a common origin. The faunas of Africa and South America are related, extremely old, and probably an expression of the drifting apart of the two continents. The fauna of southern Asia is related to that of Central Asia, and some of it appears to have entered Africa. The extremely large shore-fish faunas of the Indian and tropical Pacific oceans comprise a related complex, but the tropical shore fauna of the Atlantic, although containing Indo-Pacific components, is relatively limited and probably younger. The Arctic and Antarctic marine faunas are quite different from each other. The shore fauna of the North Pacific is quite distinct, and that of the North Atlantic more limited and probably younger. Pelagic oceanic fishes, especially those in deep waters, are similar the world over, showing little geographical isolation in terms of family groups. The deep oceanic habitat is very much the same throughout the world, but species differences do exist, showing geographical areas determined by oceanic currents and water masses.

 

All aspects of the life of a fish are closely correlated with adaptation to the total environment, physical, chemical, and biological. In studies, all the interdependent aspects of fish, such as behaviour, locomotion, reproduction, and physical and physiological characteristics, must be taken into account.

 

Correlated with their adaptation to an extremely wide variety of habitats is the extremely wide variety of life cycles that fishes display. The great majority hatch from relatively small eggs a few days to several weeks or more after the eggs are scattered in the water. Newly hatched young are still partially undeveloped and are called larvae until body structures such as fins, skeleton, and some organs are fully formed. Larval life is often very short, usually less than a few weeks, but it can be very long, some lampreys continuing as larvae for at least five years. Young and larval fishes, before reaching sexual maturity, must grow considerably, and their small size and other factors often dictate that they live in a habitat different than that of the adults. For example, most tropical marine shore fishes have pelagic larvae. Larval food also is different, and larval fishes often live in shallow waters, where they may be less exposed to predators.

 

After a fish reaches adult size, the length of its life is subject to many factors, such as innate rates of aging, predation pressure, and the nature of the local climate. The longevity of a species in the protected environment of an aquarium may have nothing to do with how long members of that species live in the wild. Many small fishes live only one to three years at the most. In some species, however, individuals may live as long as 10 or 20 or even 100 years.

 

Fish behaviour is a complicated and varied subject. As in almost all animals with a central nervous system, the nature of a response of an individual fish to stimuli from its environment depends upon the inherited characteristics of its nervous system, on what it has learned from past experience, and on the nature of the stimuli. Compared with the variety of human responses, however, that of a fish is stereotyped, not subject to much modification by “thought” or learning, and investigators must guard against anthropomorphic interpretations of fish behaviour.

 

Fishes perceive the world around them by the usual senses of sight, smell, hearing, touch, and taste and by special lateral line water-current detectors. In the few fishes that generate electric fields, a process that might best be called electrolocation aids in perception. One or another of these senses often is emphasized at the expense of others, depending upon the fish’s other adaptations. In fishes with large eyes, the sense of smell may be reduced; others, with small eyes, hunt and feed primarily by smell (such as some eels).

 

Specialized behaviour is primarily concerned with the three most important activities in the fish’s life: feeding, reproduction, and escape from enemies. Schooling behaviour of sardines on the high seas, for instance, is largely a protective device to avoid enemies, but it is also associated with and modified by their breeding and feeding requirements. Predatory fishes are often solitary, lying in wait to dart suddenly after their prey, a kind of locomotion impossible for beaked parrot fishes, which feed on coral, swimming in small groups from one coral head to the next. In addition, some predatory fishes that inhabit pelagic environments, such as tunas, often school.

 

Sleep in fishes, all of which lack true eyelids, consists of a seemingly listless state in which the fish maintains its balance but moves slowly. If attacked or disturbed, most can dart away. A few kinds of fishes lie on the bottom to sleep. Most catfishes, some loaches, and some eels and electric fishes are strictly nocturnal, being active and hunting for food during the night and retiring during the day to holes, thick vegetation, or other protective parts of the environment.

 

Communication between members of a species or between members of two or more species often is extremely important, especially in breeding behaviour (see below Reproduction). The mode of communication may be visual, as between the small so-called cleaner fish and a large fish of a very different species. The larger fish often allows the cleaner to enter its mouth to remove gill parasites. The cleaner is recognized by its distinctive colour and actions and therefore is not eaten, even if the larger fish is normally a predator. Communication is often chemical, signals being sent by specific chemicals called pheromones.

 

Many fishes have a streamlined body and swim freely in open water. Fish locomotion is closely correlated with habitat and ecological niche (the general position of the animal to its environment).

 

Many fishes in both marine and fresh waters swim at the surface and have mouths adapted to feed best (and sometimes only) at the surface. Often such fishes are long and slender, able to dart at surface insects or at other surface fishes and in turn to dart away from predators; needlefishes, halfbeaks, and topminnows (such as killifish and mosquito fish) are good examples. Oceanic flying fishes escape their predators by gathering speed above the water surface, with the lower lobe of the tail providing thrust in the water. They then glide hundreds of yards on enlarged, winglike pectoral and pelvic fins. South American freshwater flying fishes escape their enemies by jumping and propelling their strongly keeled bodies out of the water.

 

So-called mid-water swimmers, the most common type of fish, are of many kinds and live in many habitats. The powerful fusiform tunas and the trouts, for example, are adapted for strong, fast swimming, the tunas to capture prey speedily in the open ocean and the trouts to cope with the swift currents of streams and rivers. The trout body form is well adapted to many habitats. Fishes that live in relatively quiet waters such as bays or lake shores or slow rivers usually are not strong, fast swimmers but are capable of short, quick bursts of speed to escape a predator. Many of these fishes have their sides flattened, examples being the sunfish and the freshwater angelfish of aquarists. Fish associated with the bottom or substrate usually are slow swimmers. Open-water plankton-feeding fishes almost always remain fusiform and are capable of rapid, strong movement (for example, sardines and herrings of the open ocean and also many small minnows of streams and lakes).

 

Bottom-living fishes are of many kinds and have undergone many types of modification of their body shape and swimming habits. Rays, which evolved from strong-swimming mid-water sharks, usually stay close to the bottom and move by undulating their large pectoral fins. Flounders live in a similar habitat and move over the bottom by undulating the entire body. Many bottom fishes dart from place to place, resting on the bottom between movements, a motion common in gobies. One goby relative, the mudskipper, has taken to living at the edge of pools along the shore of muddy mangrove swamps. It escapes its enemies by flipping rapidly over the mud, out of the water. Some catfishes, synbranchid eels, the so-called climbing perch, and a few other fishes venture out over damp ground to find more promising waters than those that they left. They move by wriggling their bodies, sometimes using strong pectoral fins; most have accessory air-breathing organs. Many bottom-dwelling fishes live in mud holes or rocky crevices. Marine eels and gobies commonly are found in such habitats and for the most part venture far beyond their cavelike homes. Some bottom dwellers, such as the clingfishes (Gobiesocidae), have developed powerful adhesive disks that enable them to remain in place on the substrate in areas such as rocky coasts, where the action of the waves is great.

 

The methods of reproduction in fishes are varied, but most fishes lay a large number of small eggs, fertilized and scattered outside of the body. The eggs of pelagic fishes usually remain suspended in the open water. Many shore and freshwater fishes lay eggs on the bottom or among plants. Some have adhesive eggs. The mortality of the young and especially of the eggs is very high, and often only a few individuals grow to maturity out of hundreds, thousands, and in some cases millions of eggs laid.

 

Males produce sperm, usually as a milky white substance called milt, in two (sometimes one) testes within the body cavity. In bony fishes a sperm duct leads from each testis to a urogenital opening behind the vent or anus. In sharks and rays and in cyclostomes the duct leads to a cloaca. Sometimes the pelvic fins are modified to help transmit the milt to the eggs at the female’s vent or on the substrate where the female has placed them. Sometimes accessory organs are used to fertilize females internally—for example, the claspers of many sharks and rays.

 

In the females the eggs are formed in two ovaries (sometimes only one) and pass through the ovaries to the urogenital opening and to the outside. In some fishes the eggs are fertilized internally but are shed before development takes place. Members of about a dozen families each of bony fishes (teleosts) and sharks bear live young. Many skates and rays also bear live young. In some bony fishes the eggs simply develop within the female, the young emerging when the eggs hatch (ovoviviparous). Others develop within the ovary and are nourished by ovarian tissues after hatching (viviparous). There are also other methods utilized by fishes to nourish young within the female. In all live-bearers the young are born at a relatively large size and are few in number. In one family of primarily marine fishes, the surfperches from the Pacific coast of North America, Japan, and Korea, the males of at least one species are born sexually mature, although they are not fully grown.

 

Some fishes are hermaphroditic—an individual producing both sperm and eggs, usually at different stages of its life. Self-fertilization, however, is probably rare.

 

Successful reproduction and, in many cases, defense of the eggs and the young are assured by rather stereotypical but often elaborate courtship and parental behaviour, either by the male or the female or both. Some fishes prepare nests by hollowing out depressions in the sand bottom (cichlids, for example), build nests with plant materials and sticky threads excreted by the kidneys (sticklebacks), or blow a cluster of mucus-covered bubbles at the water surface (gouramis). The eggs are laid in these structures. Some varieties of cichlids and catfishes incubate eggs in their mouths.

 

Some fishes, such as salmon, undergo long migrations from the ocean and up large rivers to spawn in the gravel beds where they themselves hatched (anadromous fishes). Some, such as the freshwater eels (family Anguillidae), live and grow to maturity in fresh water and migrate to the sea to spawn (catadromous fishes). Other fishes undertake shorter migrations from lakes into streams, within the ocean, or enter spawning habitats that they do not ordinarily occupy in other ways.

 

The basic structure and function of the fish body are similar to those of all other vertebrates. The usual four types of tissues are present: surface or epithelial, connective (bone, cartilage, and fibrous tissues, as well as their derivative, blood), nerve, and muscle tissues. In addition, the fish’s organs and organ systems parallel those of other vertebrates.

 

The typical fish body is streamlined and spindle-shaped, with an anterior head, a gill apparatus, and a heart, the latter lying in the midline just below the gill chamber. The body cavity, containing the vital organs, is situated behind the head in the lower anterior part of the body. The anus usually marks the posterior termination of the body cavity and most often occurs just in front of the base of the anal fin. The spinal cord and vertebral column continue from the posterior part of the head to the base of the tail fin, passing dorsal to the body cavity and through the caudal (tail) region behind the body cavity. Most of the body is of muscular tissue, a high proportion of which is necessitated by swimming. In the course of evolution this basic body plan has been modified repeatedly into the many varieties of fish shapes that exist today.

 

The skeleton forms an integral part of the fish’s locomotion system, as well as serving to protect vital parts. The internal skeleton consists of the skull bones (except for the roofing bones of the head, which are really part of the external skeleton), the vertebral column, and the fin supports (fin rays). The fin supports are derived from the external skeleton but will be treated here because of their close functional relationship to the internal skeleton. The internal skeleton of cyclostomes, sharks, and rays is of cartilage; that of many fossil groups and some primitive living fishes is mostly of cartilage but may include some bone. In place of the vertebral column, the earliest vertebrates had a fully developed notochord, a flexible stiff rod of viscous cells surrounded by a strong fibrous sheath. During the evolution of modern fishes the rod was replaced in part by cartilage and then by ossified cartilage. Sharks and rays retain a cartilaginous vertebral column; bony fishes have spool-shaped vertebrae that in the more primitive living forms only partially replace the notochord. The skull, including the gill arches and jaws of bony fishes, is fully, or at least partially, ossified. That of sharks and rays remains cartilaginous, at times partially replaced by calcium deposits but never by true bone.

 

The supportive elements of the fins (basal or radial bones or both) have changed greatly during fish evolution. Some of these changes are described in the section below (Evolution and paleontology). Most fishes possess a single dorsal fin on the midline of the back. Many have two and a few have three dorsal fins. The other fins are the single tail and anal fins and paired pelvic and pectoral fins. A small fin, the adipose fin, with hairlike fin rays, occurs in many of the relatively primitive teleosts (such as trout) on the back near the base of the caudal fin.

 

The skin of a fish must serve many functions. It aids in maintaining the osmotic balance, provides physical protection for the body, is the site of coloration, contains sensory receptors, and, in some fishes, functions in respiration. Mucous glands, which aid in maintaining the water balance and offer protection from bacteria, are extremely numerous in fish skin, especially in cyclostomes and teleosts. Since mucous glands are present in the modern lampreys, it is reasonable to assume that they were present in primitive fishes, such as the ancient Silurian and Devonian agnathans. Protection from abrasion and predation is another function of the fish skin, and dermal (skin) bone arose early in fish evolution in response to this need. It is thought that bone first evolved in skin and only later invaded the cartilaginous areas of the fish’s body, to provide additional support and protection. There is some argument as to which came first, cartilage or bone, and fossil evidence does not settle the question. In any event, dermal bone has played an important part in fish evolution and has different characteristics in different groups of fishes. Several groups are characterized at least in part by the kind of bony scales they possess.

 

Scales have played an important part in the evolution of fishes. Primitive fishes usually had thick bony plates or thick scales in several layers of bone, enamel, and related substances. Modern teleost fishes have scales of bone, which, while still protective, allow much more freedom of motion in the body. A few modern teleosts (some catfishes, sticklebacks, and others) have secondarily acquired bony plates in the skin. Modern and early sharks possessed placoid scales, a relatively primitive type of scale with a toothlike structure, consisting of an outside layer of enamel-like substance (vitrodentine), an inner layer of dentine, and a pulp cavity containing nerves and blood vessels. Primitive bony fishes had thick scales of either the ganoid or the cosmoid type. Cosmoid scales have a hard, enamel-like outer layer, an inner layer of cosmine (a form of dentine), and then a layer of vascular bone (isopedine). In ganoid scales the hard outer layer is different chemically and is called ganoin. Under this is a cosminelike layer and then a vascular bony layer. The thin, translucent bony scales of modern fishes, called cycloid and ctenoid (the latter distinguished by serrations at the edges), lack enameloid and dentine layers.

 

Skin has several other functions in fishes. It is well supplied with nerve endings and presumably receives tactile, thermal, and pain stimuli. Skin is also well supplied with blood vessels. Some fishes breathe in part through the skin, by the exchange of oxygen and carbon dioxide between the surrounding water and numerous small blood vessels near the skin surface.

 

Skin serves as protection through the control of coloration. Fishes exhibit an almost limitless range of colours. The colours often blend closely with the surroundings, effectively hiding the animal. Many fishes use bright colours for territorial advertisement or as recognition marks for other members of their own species, or sometimes for members of other species. Many fishes can change their colour to a greater or lesser degree, by movement of pigment within the pigment cells (chromatophores). Black pigment cells (melanophores), of almost universal occurrence in fishes, are often juxtaposed with other pigment cells. When placed beneath iridocytes or leucophores (bearing the silvery or white pigment guanine), melanophores produce structural colours of blue and green. These colours are often extremely intense, because they are formed by refraction of light through the needlelike crystals of guanine. The blue and green refracted colours are often relatively pure, lacking the red and yellow rays, which have been absorbed by the black pigment (melanin) of the melanophores. Yellow, orange, and red colours are produced by erythrophores, cells containing the appropriate carotenoid pigments. Other colours are produced by combinations of melanophores, erythrophores, and iridocytes.

 

The major portion of the body of most fishes consists of muscles. Most of the mass is trunk musculature, the fin muscles usually being relatively small. The caudal fin is usually the most powerful fin, being moved by the trunk musculature. The body musculature is usually arranged in rows of chevron-shaped segments on each side. Contractions of these segments, each attached to adjacent vertebrae and vertebral processes, bends the body on the vertebral joint, producing successive undulations of the body, passing from the head to the tail, and producing driving strokes of the tail. It is the latter that provides the strong forward movement for most fishes.

 

The digestive system, in a functional sense, starts at the mouth, with the teeth used to capture prey or collect plant foods. Mouth shape and tooth structure vary greatly in fishes, depending on the kind of food normally eaten. Most fishes are predacious, feeding on small invertebrates or other fishes and have simple conical teeth on the jaws, on at least some of the bones of the roof of the mouth, and on special gill arch structures just in front of the esophagus. The latter are throat teeth. Most predacious fishes swallow their prey whole, and the teeth are used for grasping and holding prey, for orienting prey to be swallowed (head first) and for working the prey toward the esophagus. There are a variety of tooth types in fishes. Some fishes, such as sharks and piranhas, have cutting teeth for biting chunks out of their victims. A shark’s tooth, although superficially like that of a piranha, appears in many respects to be a modified scale, while that of the piranha is like that of other bony fishes, consisting of dentine and enamel. Parrot fishes have beaklike mouths with short incisor-like teeth for breaking off coral and have heavy pavementlike throat teeth for crushing the coral. Some catfishes have small brushlike teeth, arranged in rows on the jaws, for scraping plant and animal growth from rocks. Many fishes (such as the Cyprinidae or minnows) have no jaw teeth at all but have very strong throat teeth.

 

Some fishes gather planktonic food by straining it from their gill cavities with numerous elongate stiff rods (gill rakers) anchored by one end to the gill bars. The food collected on these rods is passed to the throat, where it is swallowed. Most fishes have only short gill rakers that help keep food particles from escaping out the mouth cavity into the gill chamber.

 

Once reaching the throat, food enters a short, often greatly distensible esophagus, a simple tube with a muscular wall leading into a stomach. The stomach varies greatly in fishes, depending upon the diet. In most predacious fishes it is a simple straight or curved tube or pouch with a muscular wall and a glandular lining. Food is largely digested there and leaves the stomach in liquid form.

 

Between the stomach and the intestine, ducts enter the digestive tube from the liver and pancreas. The liver is a large, clearly defined organ. The pancreas may be embedded in it, diffused through it, or broken into small parts spread along some of the intestine. The junction between the stomach and the intestine is marked by a muscular valve. Pyloric ceca (blind sacs) occur in some fishes at this junction and have a digestive or absorptive function or both.

 

The intestine itself is quite variable in length, depending upon the fish’s diet. It is short in predacious forms, sometimes no longer than the body cavity, but long in herbivorous forms, being coiled and several times longer than the entire length of the fish in some species of South American catfishes. The intestine is primarily an organ for absorbing nutrients into the bloodstream. The larger its internal surface, the greater its absorptive efficiency, and a spiral valve is one method of increasing its absorption surface.

 

Sharks, rays, chimaeras, lungfishes, surviving chondrosteans, holosteans, and even a few of the more primitive teleosts have a spiral valve or at least traces of it in the intestine. Most modern teleosts have increased the area of the intestinal walls by having numerous folds and villi (fingerlike projections) somewhat like those in humans. Undigested substances are passed to the exterior through the anus in most teleost fishes. In lungfishes, sharks, and rays, it is first passed through the cloaca, a common cavity receiving the intestinal opening and the ducts from the urogenital system.

 

Oxygen and carbon dioxide dissolve in water, and most fishes exchange dissolved oxygen and carbon dioxide in water by means of the gills. The gills lie behind and to the side of the mouth cavity and consist of fleshy filaments supported by the gill arches and filled with blood vessels, which give gills a bright red colour. Water taken in continuously through the mouth passes backward between the gill bars and over the gill filaments, where the exchange of gases takes place. The gills are protected by a gill cover in teleosts and many other fishes but by flaps of skin in sharks, rays, and some of the older fossil fish groups. The blood capillaries in the gill filaments are close to the gill surface to take up oxygen from the water and to give up excess carbon dioxide to the water.

 

Most modern fishes have a hydrostatic (ballast) organ, called the swim bladder, that lies in the body cavity just below the kidney and above the stomach and intestine. It originated as a diverticulum of the digestive canal. In advanced teleosts, especially the acanthopterygians, the bladder has lost its connection with the digestive tract, a condition called physoclistic. The connection has been retained (physostomous) by many relatively primitive teleosts. In several unrelated lines of fishes, the bladder has become specialized as a lung or, at least, as a highly vascularized accessory breathing organ. Some fishes with such accessory organs are obligate air breathers and will drown if denied access to the surface, even in well-oxygenated water. Fishes with a hydrostatic form of swim bladder can control their depth by regulating the amount of gas in the bladder. The gas, mostly oxygen, is secreted into the bladder by special glands, rendering the fish more buoyant; the gas is absorbed into the bloodstream by another special organ, reducing the overall buoyancy and allowing the fish to sink. Some deep-sea fishes may have oils, rather than gas, in the bladder. Other deep-sea and some bottom-living forms have much-reduced swim bladders or have lost the organ entirely.

 

The swim bladder of fishes follows the same developmental pattern as the lungs of land vertebrates. There is no doubt that the two structures have the same historical origin in primitive fishes. More or less intermediate forms still survive among the more primitive types of fishes, such as the lungfishes Lepidosiren and Protopterus.

 

The circulatory, or blood vascular, system consists of the heart, the arteries, the capillaries, and the veins. It is in the capillaries that the interchange of oxygen, carbon dioxide, nutrients, and other substances such as hormones and waste products takes place. The capillaries lead to the veins, which return the venous blood with its waste products to the heart, kidneys, and gills. There are two kinds of capillary beds: those in the gills and those in the rest of the body. The heart, a folded continuous muscular tube with three or four saclike enlargements, undergoes rhythmic contractions and receives venous blood in a sinus venosus. It passes the blood to an auricle and then into a thick muscular pump, the ventricle. From the ventricle the blood goes to a bulbous structure at the base of a ventral aorta just below the gills. The blood passes to the afferent (receiving) arteries of the gill arches and then to the gill capillaries. There waste gases are given off to the environment, and oxygen is absorbed. The oxygenated blood enters efferent (exuant) arteries of the gill arches and then flows into the dorsal aorta. From there blood is distributed to the tissues and organs of the body. One-way valves prevent backflow. The circulation of fishes thus differs from that of the reptiles, birds, and mammals in that oxygenated blood is not returned to the heart prior to distribution to the other parts of the body.

 

The primary excretory organ in fishes, as in other vertebrates, is the kidney. In fishes some excretion also takes place in the digestive tract, skin, and especially the gills (where ammonia is given off). Compared with land vertebrates, fishes have a special problem in maintaining their internal environment at a constant concentration of water and dissolved substances, such as salts. Proper balance of the internal environment (homeostasis) of a fish is in a great part maintained by the excretory system, especially the kidney.

 

The kidney, gills, and skin play an important role in maintaining a fish’s internal environment and checking the effects of osmosis. Marine fishes live in an environment in which the water around them has a greater concentration of salts than they can have inside their body and still maintain life. Freshwater fishes, on the other hand, live in water with a much lower concentration of salts than they require inside their bodies. Osmosis tends to promote the loss of water from the body of a marine fish and absorption of water by that of a freshwater fish. Mucus in the skin tends to slow the process but is not a sufficient barrier to prevent the movement of fluids through the permeable skin. When solutions on two sides of a permeable membrane have different concentrations of dissolved substances, water will pass through the membrane into the more concentrated solution, while the dissolved chemicals move into the area of lower concentration (diffusion).

 

The kidney of freshwater fishes is often larger in relation to body weight than that of marine fishes. In both groups the kidney excretes wastes from the body, but the kidney of freshwater fishes also excretes large amounts of water, counteracting the water absorbed through the skin. Freshwater fishes tend to lose salt to the environment and must replace it. They get some salt from their food, but the gills and skin inside the mouth actively absorb salt from water passed through the mouth. This absorption is performed by special cells capable of moving salts against the diffusion gradient. Freshwater fishes drink very little water and take in little water with their food.

 

Marine fishes must conserve water, and therefore their kidneys excrete little water. To maintain their water balance, marine fishes drink large quantities of seawater, retaining most of the water and excreting the salt. Most nitrogenous waste in marine fishes appears to be secreted by the gills as ammonia. Marine fishes can excrete salt by clusters of special cells (chloride cells) in the gills.

 

There are several teleosts—for example, the salmon—that travel between fresh water and seawater and must adjust to the reversal of osmotic gradients. They adjust their physiological processes by spending time (often surprisingly little time) in the intermediate brackish environment.

 

Marine hagfishes, sharks, and rays have osmotic concentrations in their blood about equal to that of seawater and so do not have to drink water nor perform much physiological work to maintain their osmotic balance. In sharks and rays the osmotic concentration is kept high by retention of urea in the blood. Freshwater sharks have a lowered concentration of urea in the blood.

 

Endocrine glands secrete their products into the bloodstream and body tissues and, along with the central nervous system, control and regulate many kinds of body functions. Cyclostomes have a well-developed endocrine system, and presumably it was well developed in the early Agnatha, ancestral to modern fishes. Although the endocrine system in fishes is similar to that of higher vertebrates, there are numerous differences in detail. The pituitary, the thyroid, the suprarenals, the adrenals, the pancreatic islets, the sex glands (ovaries and testes), the inner wall of the intestine, and the bodies of the ultimobranchial gland make up the endocrine system in fishes. There are some others whose function is not well understood. These organs regulate sexual activity and reproduction, growth, osmotic pressure, general metabolic activities such as the storage of fat and the utilization of foodstuffs, blood pressure, and certain aspects of skin colour. Many of these activities are also controlled in part by the central nervous system, which works with the endocrine system in maintaining the life of a fish. Some parts of the endocrine system are developmentally, and undoubtedly evolutionarily, derived from the nervous system.

 

As in all vertebrates, the nervous system of fishes is the primary mechanism coordinating body activities, as well as integrating these activities in the appropriate manner with stimuli from the environment. The central nervous system, consisting of the brain and spinal cord, is the primary integrating mechanism. The peripheral nervous system, consisting of nerves that connect the brain and spinal cord to various body organs, carries sensory information from special receptor organs such as the eyes, internal ears, nares (sense of smell), taste glands, and others to the integrating centres of the brain and spinal cord. The peripheral nervous system also carries information via different nerve cells from the integrating centres of the brain and spinal cord. This coded information is carried to the various organs and body systems, such as the skeletal muscular system, for appropriate action in response to the original external or internal stimulus. Another branch of the nervous system, the autonomic nervous system, helps to coordinate the activities of many glands and organs and is itself closely connected to the integrating centres of the brain.

 

The brain of the fish is divided into several anatomical and functional parts, all closely interconnected but each serving as the primary centre of integrating particular kinds of responses and activities. Several of these centres or parts are primarily associated with one type of sensory perception, such as sight, hearing, or smell (olfaction).

 

The sense of smell is important in almost all fishes. Certain eels with tiny eyes depend mostly on smell for location of food. The olfactory, or nasal, organ of fishes is located on the dorsal surface of the snout. The lining of the nasal organ has special sensory cells that perceive chemicals dissolved in the water, such as substances from food material, and send sensory information to the brain by way of the first cranial nerve. Odour also serves as an alarm system. Many fishes, especially various species of freshwater minnows, react with alarm to a chemical released from the skin of an injured member of their own species.

 

Many fishes have a well-developed sense of taste, and tiny pitlike taste buds or organs are located not only within their mouth cavities but also over their heads and parts of their body. Catfishes, which often have poor vision, have barbels (“whiskers”) that serve as supplementary taste organs, those around the mouth being actively used to search out food on the bottom. Some species of naturally blind cave fishes are especially well supplied with taste buds, which often cover most of their body surface.

 

Sight is extremely important in most fishes. The eye of a fish is basically like that of all other vertebrates, but the eyes of fishes are extremely varied in structure and adaptation. In general, fishes living in dark and dim water habitats have large eyes, unless they have specialized in some compensatory way so that another sense (such as smell) is dominant, in which case the eyes will often be reduced. Fishes living in brightly lighted shallow waters often will have relatively small but efficient eyes. Cyclostomes have somewhat less elaborate eyes than other fishes, with skin stretched over the eyeball perhaps making their vision somewhat less effective. Most fishes have a spherical lens and accommodate their vision to far or near subjects by moving the lens within the eyeball. A few sharks accommodate by changing the shape of the lens, as in land vertebrates. Those fishes that are heavily dependent upon the eyes have especially strong muscles for accommodation. Most fishes see well, despite the restrictions imposed by frequent turbidity of the water and by light refraction.

 

Fossil evidence suggests that colour vision evolved in fishes more than 300 million years ago, but not all living fishes have retained this ability. Experimental evidence indicates that many shallow-water fishes, if not all, have colour vision and see some colours especially well, but some bottom-dwelling shore fishes live in areas where the water is sufficiently deep to filter out most if not all colours, and these fishes apparently never see colours. When tested in shallow water, they apparently are unable to respond to colour differences.

 

Sound perception and balance are intimately associated senses in a fish. The organs of hearing are entirely internal, located within the skull, on each side of the brain and somewhat behind the eyes. Sound waves, especially those of low frequencies, travel readily through water and impinge directly upon the bones and fluids of the head and body, to be transmitted to the hearing organs. Fishes readily respond to sound; for example, a trout conditioned to escape by the approach of fishermen will take flight upon perceiving footsteps on a stream bank even if it cannot see a fisherman. Compared with humans, however, the range of sound frequencies heard by fishes is greatly restricted. Many fishes communicate with each other by producing sounds in their swim bladders, in their throats by rasping their teeth, and in other ways.

 

A fish or other vertebrate seldom has to rely on a single type of sensory information to determine the nature of the environment around it. A catfish uses taste and touch when examining a food object with its oral barbels. Like most other animals, fishes have many touch receptors over their body surface. Pain and temperature receptors also are present in fishes and presumably produce the same kind of information to a fish as to humans. Fishes react in a negative fashion to stimuli that would be painful to human beings, suggesting that they feel a sensation of pain.

 

An important sensory system in fishes that is absent in other vertebrates (except some amphibians) is the lateral line system. This consists of a series of heavily innervated small canals located in the skin and bone around the eyes, along the lower jaw, over the head, and down the mid-side of the body, where it is associated with the scales. Intermittently along these canals are located tiny sensory organs (pit organs) that apparently detect changes in pressure. The system allows a fish to sense changes in water currents and pressure, thereby helping the fish to orient itself to the various changes that occur in the physical environment.

  

Endocrine cells (insulin, blue; somatostatin, red; glucagon, green) develop in human islet-like

structures following transplantation of Pro-Islet™ into rodents. These cells produce insulin in response to glucose, effectively replacing the insulin that is lost in people with type 1 diabetes. ViaCyte has several CIRM grants to develop a stem cell-based therapy for type 1 diabetes based on this work.

 

Image taken by Kuniko Kadoya, PhD at Viacyte, Inc.

  

Fish, any of approximately 34,000 species of vertebrate animals (phylum Chordata) found in the fresh and salt waters of the world. Living species range from the primitive jawless lampreys and hagfishes through the cartilaginous sharks, skates, and rays to the abundant and diverse bony fishes. Most fish species are cold-blooded; however, one species, the opah (Lampris guttatus), is warm-blooded.

 

The term fish is applied to a variety of vertebrates of several evolutionary lines. It describes a life-form rather than a taxonomic group. As members of the phylum Chordata, fish share certain features with other vertebrates. These features are gill slits at some point in the life cycle, a notochord, or skeletal supporting rod, a dorsal hollow nerve cord, and a tail. Living fishes represent some five classes, which are as distinct from one another as are the four classes of familiar air-breathing animals—amphibians, reptiles, birds, and mammals. For example, the jawless fishes (Agnatha) have gills in pouches and lack limb girdles. Extant agnathans are the lampreys and the hagfishes. As the name implies, the skeletons of fishes of the class Chondrichthyes (from chondr, “cartilage,” and ichthyes, “fish”) are made entirely of cartilage. Modern fish of this class lack a swim bladder, and their scales and teeth are made up of the same placoid material. Sharks, skates, and rays are examples of cartilaginous fishes. The bony fishes are by far the largest class. Examples range from the tiny seahorse to the 450-kg (1,000-pound) blue marlin, from the flattened soles and flounders to the boxy puffers and ocean sunfishes. Unlike the scales of the cartilaginous fishes, those of bony fishes, when present, grow throughout life and are made up of thin overlapping plates of bone. Bony fishes also have an operculum that covers the gill slits.

 

The study of fishes, the science of ichthyology, is of broad importance. Fishes are of interest to humans for many reasons, the most important being their relationship with and dependence on the environment. A more obvious reason for interest in fishes is their role as a moderate but important part of the world’s food supply. This resource, once thought unlimited, is now realized to be finite and in delicate balance with the biological, chemical, and physical factors of the aquatic environment. Overfishing, pollution, and alteration of the environment are the chief enemies of proper fisheries management, both in fresh waters and in the ocean. (For a detailed discussion of the technology and economics of fisheries, see commercial fishing.) Another practical reason for studying fishes is their use in disease control. As predators on mosquito larvae, they help curb malaria and other mosquito-borne diseases.

 

Fishes are valuable laboratory animals in many aspects of medical and biological research. For example, the readiness of many fishes to acclimate to captivity has allowed biologists to study behaviour, physiology, and even ecology under relatively natural conditions. Fishes have been especially important in the study of animal behaviour, where research on fishes has provided a broad base for the understanding of the more flexible behaviour of the higher vertebrates. The zebra fish is used as a model in studies of gene expression.

 

There are aesthetic and recreational reasons for an interest in fishes. Millions of people keep live fishes in home aquariums for the simple pleasure of observing the beauty and behaviour of animals otherwise unfamiliar to them. Aquarium fishes provide a personal challenge to many aquarists, allowing them to test their ability to keep a small section of the natural environment in their homes. Sportfishing is another way of enjoying the natural environment, also indulged in by millions of people every year. Interest in aquarium fishes and sportfishing supports multimillion-dollar industries throughout the world.

 

Fishes have been in existence for more than 450 million years, during which time they have evolved repeatedly to fit into almost every conceivable type of aquatic habitat. In a sense, land vertebrates are simply highly modified fishes: when fishes colonized the land habitat, they became tetrapod (four-legged) land vertebrates. The popular conception of a fish as a slippery, streamlined aquatic animal that possesses fins and breathes by gills applies to many fishes, but far more fishes deviate from that conception than conform to it. For example, the body is elongate in many forms and greatly shortened in others; the body is flattened in some (principally in bottom-dwelling fishes) and laterally compressed in many others; the fins may be elaborately extended, forming intricate shapes, or they may be reduced or even lost; and the positions of the mouth, eyes, nostrils, and gill openings vary widely. Air breathers have appeared in several evolutionary lines.

 

Many fishes are cryptically coloured and shaped, closely matching their respective environments; others are among the most brilliantly coloured of all organisms, with a wide range of hues, often of striking intensity, on a single individual. The brilliance of pigments may be enhanced by the surface structure of the fish, so that it almost seems to glow. A number of unrelated fishes have actual light-producing organs. Many fishes are able to alter their coloration—some for the purpose of camouflage, others for the enhancement of behavioral signals.

 

Fishes range in adult length from less than 10 mm (0.4 inch) to more than 20 metres (60 feet) and in weight from about 1.5 grams (less than 0.06 ounce) to many thousands of kilograms. Some live in shallow thermal springs at temperatures slightly above 42 °C (100 °F), others in cold Arctic seas a few degrees below 0 °C (32 °F) or in cold deep waters more than 4,000 metres (13,100 feet) beneath the ocean surface. The structural and, especially, the physiological adaptations for life at such extremes are relatively poorly known and provide the scientifically curious with great incentive for study.

 

Almost all natural bodies of water bear fish life, the exceptions being very hot thermal ponds and extremely salt-alkaline lakes, such as the Dead Sea in Asia and the Great Salt Lake in North America. The present distribution of fishes is a result of the geological history and development of Earth as well as the ability of fishes to undergo evolutionary change and to adapt to the available habitats. Fishes may be seen to be distributed according to habitat and according to geographical area. Major habitat differences are marine and freshwater. For the most part, the fishes in a marine habitat differ from those in a freshwater habitat, even in adjacent areas, but some, such as the salmon, migrate from one to the other. The freshwater habitats may be seen to be of many kinds. Fishes found in mountain torrents, Arctic lakes, tropical lakes, temperate streams, and tropical rivers will all differ from each other, both in obvious gross structure and in physiological attributes. Even in closely adjacent habitats where, for example, a tropical mountain torrent enters a lowland stream, the fish fauna will differ. The marine habitats can be divided into deep ocean floors (benthic), mid-water oceanic (bathypelagic), surface oceanic (pelagic), rocky coast, sandy coast, muddy shores, bays, estuaries, and others. Also, for example, rocky coastal shores in tropical and temperate regions will have different fish faunas, even when such habitats occur along the same coastline.

 

Although much is known about the present geographical distribution of fishes, far less is known about how that distribution came about. Many parts of the fish fauna of the fresh waters of North America and Eurasia are related and undoubtedly have a common origin. The faunas of Africa and South America are related, extremely old, and probably an expression of the drifting apart of the two continents. The fauna of southern Asia is related to that of Central Asia, and some of it appears to have entered Africa. The extremely large shore-fish faunas of the Indian and tropical Pacific oceans comprise a related complex, but the tropical shore fauna of the Atlantic, although containing Indo-Pacific components, is relatively limited and probably younger. The Arctic and Antarctic marine faunas are quite different from each other. The shore fauna of the North Pacific is quite distinct, and that of the North Atlantic more limited and probably younger. Pelagic oceanic fishes, especially those in deep waters, are similar the world over, showing little geographical isolation in terms of family groups. The deep oceanic habitat is very much the same throughout the world, but species differences do exist, showing geographical areas determined by oceanic currents and water masses.

 

All aspects of the life of a fish are closely correlated with adaptation to the total environment, physical, chemical, and biological. In studies, all the interdependent aspects of fish, such as behaviour, locomotion, reproduction, and physical and physiological characteristics, must be taken into account.

 

Correlated with their adaptation to an extremely wide variety of habitats is the extremely wide variety of life cycles that fishes display. The great majority hatch from relatively small eggs a few days to several weeks or more after the eggs are scattered in the water. Newly hatched young are still partially undeveloped and are called larvae until body structures such as fins, skeleton, and some organs are fully formed. Larval life is often very short, usually less than a few weeks, but it can be very long, some lampreys continuing as larvae for at least five years. Young and larval fishes, before reaching sexual maturity, must grow considerably, and their small size and other factors often dictate that they live in a habitat different than that of the adults. For example, most tropical marine shore fishes have pelagic larvae. Larval food also is different, and larval fishes often live in shallow waters, where they may be less exposed to predators.

 

After a fish reaches adult size, the length of its life is subject to many factors, such as innate rates of aging, predation pressure, and the nature of the local climate. The longevity of a species in the protected environment of an aquarium may have nothing to do with how long members of that species live in the wild. Many small fishes live only one to three years at the most. In some species, however, individuals may live as long as 10 or 20 or even 100 years.

 

Fish behaviour is a complicated and varied subject. As in almost all animals with a central nervous system, the nature of a response of an individual fish to stimuli from its environment depends upon the inherited characteristics of its nervous system, on what it has learned from past experience, and on the nature of the stimuli. Compared with the variety of human responses, however, that of a fish is stereotyped, not subject to much modification by “thought” or learning, and investigators must guard against anthropomorphic interpretations of fish behaviour.

 

Fishes perceive the world around them by the usual senses of sight, smell, hearing, touch, and taste and by special lateral line water-current detectors. In the few fishes that generate electric fields, a process that might best be called electrolocation aids in perception. One or another of these senses often is emphasized at the expense of others, depending upon the fish’s other adaptations. In fishes with large eyes, the sense of smell may be reduced; others, with small eyes, hunt and feed primarily by smell (such as some eels).

 

Specialized behaviour is primarily concerned with the three most important activities in the fish’s life: feeding, reproduction, and escape from enemies. Schooling behaviour of sardines on the high seas, for instance, is largely a protective device to avoid enemies, but it is also associated with and modified by their breeding and feeding requirements. Predatory fishes are often solitary, lying in wait to dart suddenly after their prey, a kind of locomotion impossible for beaked parrot fishes, which feed on coral, swimming in small groups from one coral head to the next. In addition, some predatory fishes that inhabit pelagic environments, such as tunas, often school.

 

Sleep in fishes, all of which lack true eyelids, consists of a seemingly listless state in which the fish maintains its balance but moves slowly. If attacked or disturbed, most can dart away. A few kinds of fishes lie on the bottom to sleep. Most catfishes, some loaches, and some eels and electric fishes are strictly nocturnal, being active and hunting for food during the night and retiring during the day to holes, thick vegetation, or other protective parts of the environment.

 

Communication between members of a species or between members of two or more species often is extremely important, especially in breeding behaviour (see below Reproduction). The mode of communication may be visual, as between the small so-called cleaner fish and a large fish of a very different species. The larger fish often allows the cleaner to enter its mouth to remove gill parasites. The cleaner is recognized by its distinctive colour and actions and therefore is not eaten, even if the larger fish is normally a predator. Communication is often chemical, signals being sent by specific chemicals called pheromones.

 

Many fishes have a streamlined body and swim freely in open water. Fish locomotion is closely correlated with habitat and ecological niche (the general position of the animal to its environment).

 

Many fishes in both marine and fresh waters swim at the surface and have mouths adapted to feed best (and sometimes only) at the surface. Often such fishes are long and slender, able to dart at surface insects or at other surface fishes and in turn to dart away from predators; needlefishes, halfbeaks, and topminnows (such as killifish and mosquito fish) are good examples. Oceanic flying fishes escape their predators by gathering speed above the water surface, with the lower lobe of the tail providing thrust in the water. They then glide hundreds of yards on enlarged, winglike pectoral and pelvic fins. South American freshwater flying fishes escape their enemies by jumping and propelling their strongly keeled bodies out of the water.

 

So-called mid-water swimmers, the most common type of fish, are of many kinds and live in many habitats. The powerful fusiform tunas and the trouts, for example, are adapted for strong, fast swimming, the tunas to capture prey speedily in the open ocean and the trouts to cope with the swift currents of streams and rivers. The trout body form is well adapted to many habitats. Fishes that live in relatively quiet waters such as bays or lake shores or slow rivers usually are not strong, fast swimmers but are capable of short, quick bursts of speed to escape a predator. Many of these fishes have their sides flattened, examples being the sunfish and the freshwater angelfish of aquarists. Fish associated with the bottom or substrate usually are slow swimmers. Open-water plankton-feeding fishes almost always remain fusiform and are capable of rapid, strong movement (for example, sardines and herrings of the open ocean and also many small minnows of streams and lakes).

 

Bottom-living fishes are of many kinds and have undergone many types of modification of their body shape and swimming habits. Rays, which evolved from strong-swimming mid-water sharks, usually stay close to the bottom and move by undulating their large pectoral fins. Flounders live in a similar habitat and move over the bottom by undulating the entire body. Many bottom fishes dart from place to place, resting on the bottom between movements, a motion common in gobies. One goby relative, the mudskipper, has taken to living at the edge of pools along the shore of muddy mangrove swamps. It escapes its enemies by flipping rapidly over the mud, out of the water. Some catfishes, synbranchid eels, the so-called climbing perch, and a few other fishes venture out over damp ground to find more promising waters than those that they left. They move by wriggling their bodies, sometimes using strong pectoral fins; most have accessory air-breathing organs. Many bottom-dwelling fishes live in mud holes or rocky crevices. Marine eels and gobies commonly are found in such habitats and for the most part venture far beyond their cavelike homes. Some bottom dwellers, such as the clingfishes (Gobiesocidae), have developed powerful adhesive disks that enable them to remain in place on the substrate in areas such as rocky coasts, where the action of the waves is great.

 

The methods of reproduction in fishes are varied, but most fishes lay a large number of small eggs, fertilized and scattered outside of the body. The eggs of pelagic fishes usually remain suspended in the open water. Many shore and freshwater fishes lay eggs on the bottom or among plants. Some have adhesive eggs. The mortality of the young and especially of the eggs is very high, and often only a few individuals grow to maturity out of hundreds, thousands, and in some cases millions of eggs laid.

 

Males produce sperm, usually as a milky white substance called milt, in two (sometimes one) testes within the body cavity. In bony fishes a sperm duct leads from each testis to a urogenital opening behind the vent or anus. In sharks and rays and in cyclostomes the duct leads to a cloaca. Sometimes the pelvic fins are modified to help transmit the milt to the eggs at the female’s vent or on the substrate where the female has placed them. Sometimes accessory organs are used to fertilize females internally—for example, the claspers of many sharks and rays.

 

In the females the eggs are formed in two ovaries (sometimes only one) and pass through the ovaries to the urogenital opening and to the outside. In some fishes the eggs are fertilized internally but are shed before development takes place. Members of about a dozen families each of bony fishes (teleosts) and sharks bear live young. Many skates and rays also bear live young. In some bony fishes the eggs simply develop within the female, the young emerging when the eggs hatch (ovoviviparous). Others develop within the ovary and are nourished by ovarian tissues after hatching (viviparous). There are also other methods utilized by fishes to nourish young within the female. In all live-bearers the young are born at a relatively large size and are few in number. In one family of primarily marine fishes, the surfperches from the Pacific coast of North America, Japan, and Korea, the males of at least one species are born sexually mature, although they are not fully grown.

 

Some fishes are hermaphroditic—an individual producing both sperm and eggs, usually at different stages of its life. Self-fertilization, however, is probably rare.

 

Successful reproduction and, in many cases, defense of the eggs and the young are assured by rather stereotypical but often elaborate courtship and parental behaviour, either by the male or the female or both. Some fishes prepare nests by hollowing out depressions in the sand bottom (cichlids, for example), build nests with plant materials and sticky threads excreted by the kidneys (sticklebacks), or blow a cluster of mucus-covered bubbles at the water surface (gouramis). The eggs are laid in these structures. Some varieties of cichlids and catfishes incubate eggs in their mouths.

 

Some fishes, such as salmon, undergo long migrations from the ocean and up large rivers to spawn in the gravel beds where they themselves hatched (anadromous fishes). Some, such as the freshwater eels (family Anguillidae), live and grow to maturity in fresh water and migrate to the sea to spawn (catadromous fishes). Other fishes undertake shorter migrations from lakes into streams, within the ocean, or enter spawning habitats that they do not ordinarily occupy in other ways.

 

The basic structure and function of the fish body are similar to those of all other vertebrates. The usual four types of tissues are present: surface or epithelial, connective (bone, cartilage, and fibrous tissues, as well as their derivative, blood), nerve, and muscle tissues. In addition, the fish’s organs and organ systems parallel those of other vertebrates.

 

The typical fish body is streamlined and spindle-shaped, with an anterior head, a gill apparatus, and a heart, the latter lying in the midline just below the gill chamber. The body cavity, containing the vital organs, is situated behind the head in the lower anterior part of the body. The anus usually marks the posterior termination of the body cavity and most often occurs just in front of the base of the anal fin. The spinal cord and vertebral column continue from the posterior part of the head to the base of the tail fin, passing dorsal to the body cavity and through the caudal (tail) region behind the body cavity. Most of the body is of muscular tissue, a high proportion of which is necessitated by swimming. In the course of evolution this basic body plan has been modified repeatedly into the many varieties of fish shapes that exist today.

 

The skeleton forms an integral part of the fish’s locomotion system, as well as serving to protect vital parts. The internal skeleton consists of the skull bones (except for the roofing bones of the head, which are really part of the external skeleton), the vertebral column, and the fin supports (fin rays). The fin supports are derived from the external skeleton but will be treated here because of their close functional relationship to the internal skeleton. The internal skeleton of cyclostomes, sharks, and rays is of cartilage; that of many fossil groups and some primitive living fishes is mostly of cartilage but may include some bone. In place of the vertebral column, the earliest vertebrates had a fully developed notochord, a flexible stiff rod of viscous cells surrounded by a strong fibrous sheath. During the evolution of modern fishes the rod was replaced in part by cartilage and then by ossified cartilage. Sharks and rays retain a cartilaginous vertebral column; bony fishes have spool-shaped vertebrae that in the more primitive living forms only partially replace the notochord. The skull, including the gill arches and jaws of bony fishes, is fully, or at least partially, ossified. That of sharks and rays remains cartilaginous, at times partially replaced by calcium deposits but never by true bone.

 

The supportive elements of the fins (basal or radial bones or both) have changed greatly during fish evolution. Some of these changes are described in the section below (Evolution and paleontology). Most fishes possess a single dorsal fin on the midline of the back. Many have two and a few have three dorsal fins. The other fins are the single tail and anal fins and paired pelvic and pectoral fins. A small fin, the adipose fin, with hairlike fin rays, occurs in many of the relatively primitive teleosts (such as trout) on the back near the base of the caudal fin.

 

The skin of a fish must serve many functions. It aids in maintaining the osmotic balance, provides physical protection for the body, is the site of coloration, contains sensory receptors, and, in some fishes, functions in respiration. Mucous glands, which aid in maintaining the water balance and offer protection from bacteria, are extremely numerous in fish skin, especially in cyclostomes and teleosts. Since mucous glands are present in the modern lampreys, it is reasonable to assume that they were present in primitive fishes, such as the ancient Silurian and Devonian agnathans. Protection from abrasion and predation is another function of the fish skin, and dermal (skin) bone arose early in fish evolution in response to this need. It is thought that bone first evolved in skin and only later invaded the cartilaginous areas of the fish’s body, to provide additional support and protection. There is some argument as to which came first, cartilage or bone, and fossil evidence does not settle the question. In any event, dermal bone has played an important part in fish evolution and has different characteristics in different groups of fishes. Several groups are characterized at least in part by the kind of bony scales they possess.

 

Scales have played an important part in the evolution of fishes. Primitive fishes usually had thick bony plates or thick scales in several layers of bone, enamel, and related substances. Modern teleost fishes have scales of bone, which, while still protective, allow much more freedom of motion in the body. A few modern teleosts (some catfishes, sticklebacks, and others) have secondarily acquired bony plates in the skin. Modern and early sharks possessed placoid scales, a relatively primitive type of scale with a toothlike structure, consisting of an outside layer of enamel-like substance (vitrodentine), an inner layer of dentine, and a pulp cavity containing nerves and blood vessels. Primitive bony fishes had thick scales of either the ganoid or the cosmoid type. Cosmoid scales have a hard, enamel-like outer layer, an inner layer of cosmine (a form of dentine), and then a layer of vascular bone (isopedine). In ganoid scales the hard outer layer is different chemically and is called ganoin. Under this is a cosminelike layer and then a vascular bony layer. The thin, translucent bony scales of modern fishes, called cycloid and ctenoid (the latter distinguished by serrations at the edges), lack enameloid and dentine layers.

 

Skin has several other functions in fishes. It is well supplied with nerve endings and presumably receives tactile, thermal, and pain stimuli. Skin is also well supplied with blood vessels. Some fishes breathe in part through the skin, by the exchange of oxygen and carbon dioxide between the surrounding water and numerous small blood vessels near the skin surface.

 

Skin serves as protection through the control of coloration. Fishes exhibit an almost limitless range of colours. The colours often blend closely with the surroundings, effectively hiding the animal. Many fishes use bright colours for territorial advertisement or as recognition marks for other members of their own species, or sometimes for members of other species. Many fishes can change their colour to a greater or lesser degree, by movement of pigment within the pigment cells (chromatophores). Black pigment cells (melanophores), of almost universal occurrence in fishes, are often juxtaposed with other pigment cells. When placed beneath iridocytes or leucophores (bearing the silvery or white pigment guanine), melanophores produce structural colours of blue and green. These colours are often extremely intense, because they are formed by refraction of light through the needlelike crystals of guanine. The blue and green refracted colours are often relatively pure, lacking the red and yellow rays, which have been absorbed by the black pigment (melanin) of the melanophores. Yellow, orange, and red colours are produced by erythrophores, cells containing the appropriate carotenoid pigments. Other colours are produced by combinations of melanophores, erythrophores, and iridocytes.

 

The major portion of the body of most fishes consists of muscles. Most of the mass is trunk musculature, the fin muscles usually being relatively small. The caudal fin is usually the most powerful fin, being moved by the trunk musculature. The body musculature is usually arranged in rows of chevron-shaped segments on each side. Contractions of these segments, each attached to adjacent vertebrae and vertebral processes, bends the body on the vertebral joint, producing successive undulations of the body, passing from the head to the tail, and producing driving strokes of the tail. It is the latter that provides the strong forward movement for most fishes.

 

The digestive system, in a functional sense, starts at the mouth, with the teeth used to capture prey or collect plant foods. Mouth shape and tooth structure vary greatly in fishes, depending on the kind of food normally eaten. Most fishes are predacious, feeding on small invertebrates or other fishes and have simple conical teeth on the jaws, on at least some of the bones of the roof of the mouth, and on special gill arch structures just in front of the esophagus. The latter are throat teeth. Most predacious fishes swallow their prey whole, and the teeth are used for grasping and holding prey, for orienting prey to be swallowed (head first) and for working the prey toward the esophagus. There are a variety of tooth types in fishes. Some fishes, such as sharks and piranhas, have cutting teeth for biting chunks out of their victims. A shark’s tooth, although superficially like that of a piranha, appears in many respects to be a modified scale, while that of the piranha is like that of other bony fishes, consisting of dentine and enamel. Parrot fishes have beaklike mouths with short incisor-like teeth for breaking off coral and have heavy pavementlike throat teeth for crushing the coral. Some catfishes have small brushlike teeth, arranged in rows on the jaws, for scraping plant and animal growth from rocks. Many fishes (such as the Cyprinidae or minnows) have no jaw teeth at all but have very strong throat teeth.

 

Some fishes gather planktonic food by straining it from their gill cavities with numerous elongate stiff rods (gill rakers) anchored by one end to the gill bars. The food collected on these rods is passed to the throat, where it is swallowed. Most fishes have only short gill rakers that help keep food particles from escaping out the mouth cavity into the gill chamber.

 

Once reaching the throat, food enters a short, often greatly distensible esophagus, a simple tube with a muscular wall leading into a stomach. The stomach varies greatly in fishes, depending upon the diet. In most predacious fishes it is a simple straight or curved tube or pouch with a muscular wall and a glandular lining. Food is largely digested there and leaves the stomach in liquid form.

 

Between the stomach and the intestine, ducts enter the digestive tube from the liver and pancreas. The liver is a large, clearly defined organ. The pancreas may be embedded in it, diffused through it, or broken into small parts spread along some of the intestine. The junction between the stomach and the intestine is marked by a muscular valve. Pyloric ceca (blind sacs) occur in some fishes at this junction and have a digestive or absorptive function or both.

 

The intestine itself is quite variable in length, depending upon the fish’s diet. It is short in predacious forms, sometimes no longer than the body cavity, but long in herbivorous forms, being coiled and several times longer than the entire length of the fish in some species of South American catfishes. The intestine is primarily an organ for absorbing nutrients into the bloodstream. The larger its internal surface, the greater its absorptive efficiency, and a spiral valve is one method of increasing its absorption surface.

 

Sharks, rays, chimaeras, lungfishes, surviving chondrosteans, holosteans, and even a few of the more primitive teleosts have a spiral valve or at least traces of it in the intestine. Most modern teleosts have increased the area of the intestinal walls by having numerous folds and villi (fingerlike projections) somewhat like those in humans. Undigested substances are passed to the exterior through the anus in most teleost fishes. In lungfishes, sharks, and rays, it is first passed through the cloaca, a common cavity receiving the intestinal opening and the ducts from the urogenital system.

 

Oxygen and carbon dioxide dissolve in water, and most fishes exchange dissolved oxygen and carbon dioxide in water by means of the gills. The gills lie behind and to the side of the mouth cavity and consist of fleshy filaments supported by the gill arches and filled with blood vessels, which give gills a bright red colour. Water taken in continuously through the mouth passes backward between the gill bars and over the gill filaments, where the exchange of gases takes place. The gills are protected by a gill cover in teleosts and many other fishes but by flaps of skin in sharks, rays, and some of the older fossil fish groups. The blood capillaries in the gill filaments are close to the gill surface to take up oxygen from the water and to give up excess carbon dioxide to the water.

 

Most modern fishes have a hydrostatic (ballast) organ, called the swim bladder, that lies in the body cavity just below the kidney and above the stomach and intestine. It originated as a diverticulum of the digestive canal. In advanced teleosts, especially the acanthopterygians, the bladder has lost its connection with the digestive tract, a condition called physoclistic. The connection has been retained (physostomous) by many relatively primitive teleosts. In several unrelated lines of fishes, the bladder has become specialized as a lung or, at least, as a highly vascularized accessory breathing organ. Some fishes with such accessory organs are obligate air breathers and will drown if denied access to the surface, even in well-oxygenated water. Fishes with a hydrostatic form of swim bladder can control their depth by regulating the amount of gas in the bladder. The gas, mostly oxygen, is secreted into the bladder by special glands, rendering the fish more buoyant; the gas is absorbed into the bloodstream by another special organ, reducing the overall buoyancy and allowing the fish to sink. Some deep-sea fishes may have oils, rather than gas, in the bladder. Other deep-sea and some bottom-living forms have much-reduced swim bladders or have lost the organ entirely.

 

The swim bladder of fishes follows the same developmental pattern as the lungs of land vertebrates. There is no doubt that the two structures have the same historical origin in primitive fishes. More or less intermediate forms still survive among the more primitive types of fishes, such as the lungfishes Lepidosiren and Protopterus.

 

The circulatory, or blood vascular, system consists of the heart, the arteries, the capillaries, and the veins. It is in the capillaries that the interchange of oxygen, carbon dioxide, nutrients, and other substances such as hormones and waste products takes place. The capillaries lead to the veins, which return the venous blood with its waste products to the heart, kidneys, and gills. There are two kinds of capillary beds: those in the gills and those in the rest of the body. The heart, a folded continuous muscular tube with three or four saclike enlargements, undergoes rhythmic contractions and receives venous blood in a sinus venosus. It passes the blood to an auricle and then into a thick muscular pump, the ventricle. From the ventricle the blood goes to a bulbous structure at the base of a ventral aorta just below the gills. The blood passes to the afferent (receiving) arteries of the gill arches and then to the gill capillaries. There waste gases are given off to the environment, and oxygen is absorbed. The oxygenated blood enters efferent (exuant) arteries of the gill arches and then flows into the dorsal aorta. From there blood is distributed to the tissues and organs of the body. One-way valves prevent backflow. The circulation of fishes thus differs from that of the reptiles, birds, and mammals in that oxygenated blood is not returned to the heart prior to distribution to the other parts of the body.

 

The primary excretory organ in fishes, as in other vertebrates, is the kidney. In fishes some excretion also takes place in the digestive tract, skin, and especially the gills (where ammonia is given off). Compared with land vertebrates, fishes have a special problem in maintaining their internal environment at a constant concentration of water and dissolved substances, such as salts. Proper balance of the internal environment (homeostasis) of a fish is in a great part maintained by the excretory system, especially the kidney.

 

The kidney, gills, and skin play an important role in maintaining a fish’s internal environment and checking the effects of osmosis. Marine fishes live in an environment in which the water around them has a greater concentration of salts than they can have inside their body and still maintain life. Freshwater fishes, on the other hand, live in water with a much lower concentration of salts than they require inside their bodies. Osmosis tends to promote the loss of water from the body of a marine fish and absorption of water by that of a freshwater fish. Mucus in the skin tends to slow the process but is not a sufficient barrier to prevent the movement of fluids through the permeable skin. When solutions on two sides of a permeable membrane have different concentrations of dissolved substances, water will pass through the membrane into the more concentrated solution, while the dissolved chemicals move into the area of lower concentration (diffusion).

 

The kidney of freshwater fishes is often larger in relation to body weight than that of marine fishes. In both groups the kidney excretes wastes from the body, but the kidney of freshwater fishes also excretes large amounts of water, counteracting the water absorbed through the skin. Freshwater fishes tend to lose salt to the environment and must replace it. They get some salt from their food, but the gills and skin inside the mouth actively absorb salt from water passed through the mouth. This absorption is performed by special cells capable of moving salts against the diffusion gradient. Freshwater fishes drink very little water and take in little water with their food.

 

Marine fishes must conserve water, and therefore their kidneys excrete little water. To maintain their water balance, marine fishes drink large quantities of seawater, retaining most of the water and excreting the salt. Most nitrogenous waste in marine fishes appears to be secreted by the gills as ammonia. Marine fishes can excrete salt by clusters of special cells (chloride cells) in the gills.

 

There are several teleosts—for example, the salmon—that travel between fresh water and seawater and must adjust to the reversal of osmotic gradients. They adjust their physiological processes by spending time (often surprisingly little time) in the intermediate brackish environment.

 

Marine hagfishes, sharks, and rays have osmotic concentrations in their blood about equal to that of seawater and so do not have to drink water nor perform much physiological work to maintain their osmotic balance. In sharks and rays the osmotic concentration is kept high by retention of urea in the blood. Freshwater sharks have a lowered concentration of urea in the blood.

 

Endocrine glands secrete their products into the bloodstream and body tissues and, along with the central nervous system, control and regulate many kinds of body functions. Cyclostomes have a well-developed endocrine system, and presumably it was well developed in the early Agnatha, ancestral to modern fishes. Although the endocrine system in fishes is similar to that of higher vertebrates, there are numerous differences in detail. The pituitary, the thyroid, the suprarenals, the adrenals, the pancreatic islets, the sex glands (ovaries and testes), the inner wall of the intestine, and the bodies of the ultimobranchial gland make up the endocrine system in fishes. There are some others whose function is not well understood. These organs regulate sexual activity and reproduction, growth, osmotic pressure, general metabolic activities such as the storage of fat and the utilization of foodstuffs, blood pressure, and certain aspects of skin colour. Many of these activities are also controlled in part by the central nervous system, which works with the endocrine system in maintaining the life of a fish. Some parts of the endocrine system are developmentally, and undoubtedly evolutionarily, derived from the nervous system.

 

As in all vertebrates, the nervous system of fishes is the primary mechanism coordinating body activities, as well as integrating these activities in the appropriate manner with stimuli from the environment. The central nervous system, consisting of the brain and spinal cord, is the primary integrating mechanism. The peripheral nervous system, consisting of nerves that connect the brain and spinal cord to various body organs, carries sensory information from special receptor organs such as the eyes, internal ears, nares (sense of smell), taste glands, and others to the integrating centres of the brain and spinal cord. The peripheral nervous system also carries information via different nerve cells from the integrating centres of the brain and spinal cord. This coded information is carried to the various organs and body systems, such as the skeletal muscular system, for appropriate action in response to the original external or internal stimulus. Another branch of the nervous system, the autonomic nervous system, helps to coordinate the activities of many glands and organs and is itself closely connected to the integrating centres of the brain.

 

The brain of the fish is divided into several anatomical and functional parts, all closely interconnected but each serving as the primary centre of integrating particular kinds of responses and activities. Several of these centres or parts are primarily associated with one type of sensory perception, such as sight, hearing, or smell (olfaction).

 

The sense of smell is important in almost all fishes. Certain eels with tiny eyes depend mostly on smell for location of food. The olfactory, or nasal, organ of fishes is located on the dorsal surface of the snout. The lining of the nasal organ has special sensory cells that perceive chemicals dissolved in the water, such as substances from food material, and send sensory information to the brain by way of the first cranial nerve. Odour also serves as an alarm system. Many fishes, especially various species of freshwater minnows, react with alarm to a chemical released from the skin of an injured member of their own species.

 

Many fishes have a well-developed sense of taste, and tiny pitlike taste buds or organs are located not only within their mouth cavities but also over their heads and parts of their body. Catfishes, which often have poor vision, have barbels (“whiskers”) that serve as supplementary taste organs, those around the mouth being actively used to search out food on the bottom. Some species of naturally blind cave fishes are especially well supplied with taste buds, which often cover most of their body surface.

 

Sight is extremely important in most fishes. The eye of a fish is basically like that of all other vertebrates, but the eyes of fishes are extremely varied in structure and adaptation. In general, fishes living in dark and dim water habitats have large eyes, unless they have specialized in some compensatory way so that another sense (such as smell) is dominant, in which case the eyes will often be reduced. Fishes living in brightly lighted shallow waters often will have relatively small but efficient eyes. Cyclostomes have somewhat less elaborate eyes than other fishes, with skin stretched over the eyeball perhaps making their vision somewhat less effective. Most fishes have a spherical lens and accommodate their vision to far or near subjects by moving the lens within the eyeball. A few sharks accommodate by changing the shape of the lens, as in land vertebrates. Those fishes that are heavily dependent upon the eyes have especially strong muscles for accommodation. Most fishes see well, despite the restrictions imposed by frequent turbidity of the water and by light refraction.

 

Fossil evidence suggests that colour vision evolved in fishes more than 300 million years ago, but not all living fishes have retained this ability. Experimental evidence indicates that many shallow-water fishes, if not all, have colour vision and see some colours especially well, but some bottom-dwelling shore fishes live in areas where the water is sufficiently deep to filter out most if not all colours, and these fishes apparently never see colours. When tested in shallow water, they apparently are unable to respond to colour differences.

 

Sound perception and balance are intimately associated senses in a fish. The organs of hearing are entirely internal, located within the skull, on each side of the brain and somewhat behind the eyes. Sound waves, especially those of low frequencies, travel readily through water and impinge directly upon the bones and fluids of the head and body, to be transmitted to the hearing organs. Fishes readily respond to sound; for example, a trout conditioned to escape by the approach of fishermen will take flight upon perceiving footsteps on a stream bank even if it cannot see a fisherman. Compared with humans, however, the range of sound frequencies heard by fishes is greatly restricted. Many fishes communicate with each other by producing sounds in their swim bladders, in their throats by rasping their teeth, and in other ways.

 

A fish or other vertebrate seldom has to rely on a single type of sensory information to determine the nature of the environment around it. A catfish uses taste and touch when examining a food object with its oral barbels. Like most other animals, fishes have many touch receptors over their body surface. Pain and temperature receptors also are present in fishes and presumably produce the same kind of information to a fish as to humans. Fishes react in a negative fashion to stimuli that would be painful to human beings, suggesting that they feel a sensation of pain.

 

An important sensory system in fishes that is absent in other vertebrates (except some amphibians) is the lateral line system. This consists of a series of heavily innervated small canals located in the skin and bone around the eyes, along the lower jaw, over the head, and down the mid-side of the body, where it is associated with the scales. Intermittently along these canals are located tiny sensory organs (pit organs) that apparently detect changes in pressure. The system allows a fish to sense changes in water currents and pressure, thereby helping the fish to orient itself to the various changes that occur in the physical environment.

 

Although a great many fossil fishes have been found and described, they represent a tiny portion of the long and complex evolution of fishes, and knowledge of fish evolution remains relatively fragmentary. In the classification presented in this article, fishlike vertebrates are divided into seven categories, the members of each having a different basic structural organization and different physical and physiological adaptations for the problems presented by the environment. The broad basic pattern has been one of successive replacement of older groups by newer, better-adapted groups. One or a few members of a group evolved a basically more efficient means of feeding, breathing, or swimming or several better ways of living. These better-adapted groups then forced the extinction of members of the older group with which they competed for available food, breeding places, or other necessities of life. As the new fishes became well established, some of them evolved further and adapted to other habitats, where they continued to replace members of the old group already there. The process was repeated until all or almost all members of the old group in a variety of habitats had been replaced by members of the newer evolutionary line.

 

The earliest vertebrate fossils of certain relationships are fragments of dermal armour of jawless fishes (superclass Agnatha, order Heterostraci) from the Upper Ordovician Period in North America, about 450 million years in age. Early Ordovician toothlike fragments from the former Soviet Union are less certainly remains of agnathans. It is uncertain whether the North American jawless fishes inhabited shallow coastal marine waters, where their remains became fossilized, or were freshwater vertebrates washed into coastal deposits by stream action.

 

Jawless fishes probably arose from ancient, small, soft-bodied filter-feeding organisms much like and probably also ancestral to the modern sand-dwelling filter feeders, the Cephalochordata (Amphioxus and its relatives). The body in the ancestral animals was probably stiffened by a notochord. Although a vertebrate origin in fresh water is much debated by paleontologists, it is possible that mobility of the body and protection provided by dermal armour arose in response to streamflow in the freshwater environment and to the need to escape from and resist the clawed invertebrate eurypterids that lived in the same waters. Because of the marine distribution of the surviving primitive chordates, however, many paleontologists doubt that the vertebrates arose in fresh water.

 

Heterostracan remains are next found in what appear to be delta deposits in two North American localities of Silurian age. By the close of the Silurian, about 416 million years ago, European heterostracan remains are found in what appear to be delta or coastal deposits. In the Late Silurian of the Baltic area, lagoon or freshwater deposits yield jawless fishes of the order Osteostraci. Somewhat later in the Silurian from the same region, layers contain fragments of jawed acanthodians, the earliest group of jawed vertebrates, and of jawless fishes. These layers lie between marine beds but appear to be washed out from fresh waters of a coastal region.

 

It is evident, therefore, that by the end of the Silurian both jawed and jawless vertebrates were well established and already must have had a long history of development. Yet paleontologists have remains only of specialized forms that cannot have been the ancestors of the placoderms and bony fishes that appear in the next period, the Devonian. No fossils are known of the more primitive ancestors of the agnathans and acanthodians. The extensive marine beds of the Silurian and those of the Ordovician are essentially void of vertebrate history. It is believed that the ancestors of fishlike vertebrates evolved in upland fresh waters, where whatever few and relatively small fossil beds were made probably have been long since eroded away. Remains of the earliest vertebrates may never be found.

 

By the close of the Silurian, all known orders of jawless vertebrates had evolved, except perhaps the modern cyclostomes, which are without the hard parts that ordinarily are preserved as fossils. Cyclostomes were unknown as fossils until 1968, when a lamprey of modern body structure was reported from the Middle Pennsylvanian of Illinois, in deposits more than 300 million years old. Fossil evidence of the four orders of armoured jawless vertebrates is absent from deposits later than the Devonian. Presumably, these vertebrates became extinct at that time, being replaced by the more efficient and probably more aggressive placoderms, acanthodians, selachians (sharks and relatives), and by early bony fishes. Cyclostomes survived probably because early on they evolved from anaspid agnathans and developed a rasping tonguelike structure and a sucking mouth, enabling them to prey on other fishes. With this way of life they apparently had no competition from other fish groups. Cyclostomes, the hagfishes and lampreys, were once thought to be closely related because of the similarity in their suctorial mouths, but it is now understood that the hagfishes, order Myxiniformes, are the most primitive living chordates, and they are classified separately from the lampreys, order Petromyzontiformes.

 

Early jawless vertebrates probably fed on tiny organisms by filter feeding, as do the larvae of their descendants, the modern lampreys. The gill cavity of the early agnathans was large. It is thought that small organisms taken from the bottom by a nibbling action of the mouth, or more certainly by a sucking action through the mouth, were passed into the gill cavity along with water for breathing. Small organisms then were strained out by the gill apparatus and directed to the food canal. The gill apparatus thus evolved as a feeding, as well as a breathing, structure. The head and gills in the agnathans were protected by a heavy dermal armour; the tail region was free, allowing motion for swimming.

 

Most important for the evolution of fishes and vertebrates in general was the early appearance of bone, cartilage, and enamel-like substance. These materials became modified in later fishes, enabling them to adapt to many aquatic environments and finally even to land. Other basic organs and tissues of the vertebrates—such as the central nervous system, heart, liver, digestive tract, kidney, and circulatory system— undoubtedly were present in the ancestors of the agnathans. In many ways, bone, both external and internal, was the key to vertebrate evolution.

 

The next class of fishes to appear was the Acanthodii, containing the earliest known jawed vertebrates, which arose in the Late Silurian, more than 416 million years ago. The acanthodians declined after the Devonian but lasted into the Early Permian, a little less than 280 million years ago. The first complete specimens appear in Lower Devonian freshwater deposits, but later in the Devonian and Permian some members appear to have been marine. Most were small fishes, not more than 75 cm (approximately 30 inches) in length.

 

We know nothing of the ancestors of the acanthodians. They must have arisen from some jawless vertebrate, probably in fresh water. They appear to have been active swimmers with almost no head armour but with large eyes, indicating that they depended heavily on vision. Perhaps they preyed on invertebrates. The rows of spines and spinelike fins between the pectoral and pelvic fins give some credence to the idea that paired fins arose from “fin folds” along the body sides.

 

The relationships of the acanthodians to other jawed vertebrates are obscure. They possess features found in both sharks and bony fishes. They are like early bony fishes in possessing ganoidlike scales and a partially ossified internal skeleton. Certain aspects of the jaw appear to be more like those of bony fishes than sharks, but the bony fin spines and certain aspects of the gill apparatus would seem to favour relationships with early sharks. Acanthodians do not seem particularly close to the Placodermi, although, like the placoderms, they apparently possessed less efficient tooth replacement and tooth structure than the sharks and the bony fishes, possibly one reason for their subsequent extinction.

The active ingredient in most birth control pills winds up in rivers, lakes and estuaries, where it can harm wildlife.

Hippopotamuses love water, which is why the Greeks named them the "river horse." Hippos spend up to 16 hours a day submerged in rivers and lakes to keep their massive bodies cool under the hot African sun. Hippos are graceful in water, good swimmers, and can hold their breath underwater for up to five minutes. However, they are often large enough to simply walk or stand on the lake floor, or lie in the shallows. Their eyes and nostrils are located high on their heads, which allows them to see and breathe while mostly submerged. Hippos also bask on the shoreline and secrete an oily red substance, which gave rise to the myth that they sweat blood. The liquid is actually a skin moistener and sunblock that may also provide protection against germs. At sunset, hippopotamuses leave the water and travel overland to graze. They may travel 6 miles (10 kilometers) in a night, along single-file pathways, to consume some 80 pounds (35 kilograms) of grass. Considering their enormous size, a hippo's food intake is relatively low. If threatened on land hippos may run for the water—they can match a human's speed for short distances. Hippo calves weigh nearly 100 pounds (45 kilograms) at birth and can suckle on land or underwater by closing their ears and nostrils. Each female has only one calf every two years. Soon after birth, mother and young join schools that provide some protection against crocodiles, lions, and hyenas. Hippos once had a broader distribution but now live in eastern central and southern sub-Saharan Africa, where their populations are in decline. A partially submerged hippopotamus tries to keep cool in the hot African sun. The hippopotamus (Hippopotamus amphibius), or hippo, from the ancient Greek for "river horse" (ἱπποπόταμος), is a large, mostly herbivorous mammal in sub-Saharan Africa, and one of only two extant species in the family Hippopotamidae (the other is the Pygmy Hippopotamus.) After the elephant and rhinoceros, the hippopotamus is the third largest land mammal and the heaviest extant artiodactyl. Despite their physical resemblance to pigs and other terrestrial even-toed ungulates, their closest living relatives are cetaceans (whales, porpoises, etc.) from which they diverged about 55 million years ago. The common ancestor of whales and hippos split from other even-toed ungulates around 60 million years ago. The earliest known hippopotamus fossils, belonging to the genus Kenyapotamus in Africa, date to around 16 million years ago.

The hippopotamus is semi-aquatic, inhabiting rivers, lakes and mangrove swamps, where territorial bulls preside over a stretch of river and groups of 5 to 30 females and young. During the day they remain cool by staying in the water or mud; reproduction and childbirth both occur in water. They emerge at dusk to graze on grass. While hippopotamuses rest near each other in the water, grazing is a solitary activity and hippos are not territorial on land. Hippos are recognizable by their barrel-shaped torso, enormous mouth and teeth, nearly hairless body, stubby legs and tremendous size. It is the third largest land mammal by weight (between 1½ and 3 tonnes), behind the white rhinoceros (1½ to 3½ tonnes) and the three species of elephant (3 to 9 tonnes). The hippopotamus is one of the largest quadrupeds and despite its stocky shape and short legs, it can easily outrun a human. Hippos have been clocked at 30 km/h (19 mph) over short distances. The hippopotamus is one of the most aggressive creatures in the world and is often regarded as one of the most dangerous animals in Africa. They are still threatened by habitat loss and poaching for their meat and ivory canine teeth. There is also a colony of non-zoo hippos in Colombia introduced by Pablo Escobar. The most recent theory of the origins of Hippopotamidae suggests that hippos and whales shared a common semi-aquatic ancestor that branched off from other artiodactyls around 60 million years ago.[13][15] This hypothesized ancestral group likely split into two branches around 54 million years ago.[12] One branch would evolve into cetaceans, possibly beginning about 52 million years ago with the proto-whale Pakicetus and other early whale ancestors collectively known as Archaeoceti, which eventually underwent aquatic adaptation into the completely aquatic cetaceans.[17] The other branch became the anthracotheres, a large family of four-legged beasts, the earliest of whom in the late Eocene would have resembled skinny hippopotamuses with comparatively small and narrow heads. All branches of the anthracotheres, except that which evolved into Hippopotamidae, became extinct during the Pliocene without leaving any descendants.[15]

A rough evolutionary lineage can be traced from Eocene and Oligocene species: Anthracotherium and Elomeryx to the Miocene Merycopotamus and Libycosaurus and the very latest anthracotheres in the Pliocene.[18] Merycopotamus, Libycosaurus and all hippopotamids can be considered to form a clade, with Libycosaurus being more closely related to hippos. Their common ancestor would have lived in the Miocene, about 20 million years ago. Hippopotamids are therefore deeply nested within the family Anthracotheriidae. The Hippopotamidae are believed to have evolved in Africa; the oldest known hippopotamid is the genus Kenyapotamus which lived in Africa from 16 to 8 million years ago. While hippopotamid species spread across Asia and Europe, no hippopotamuses have ever been discovered in the Americas, although various anthracothere genera emigrated into North America during the early Oligocene. From 7.5 to 1.8 million years ago an ancestor to the modern hippopotamus, Archaeopotamus, lived in Africa and the Middle East.[19]

While the fossil record of hippos is still poorly understood, the two modern genera, Hippopotamus and Choeropsis (sometimes Hexaprotodon), may have diverged as far back as 8 million years ago. Taxonomists disagree whether or not the modern Pygmy Hippopotamus is a member of Hexaprotodon —an apparently paraphyletic genus also embracing many extinct Asian hippopotamuses that is more closely related to Hippopotamus, or Choeropsis —an older and basal genus.[18][19]

[edit]Extinct species

Three species of Malagasy Hippopotamus became extinct during the Holocene on Madagascar, one of them within the past 1,000 years. The Malagasy Hippos were smaller than the modern hippopotamus, likely through the process of insular dwarfism.[20] There is fossil evidence that many Malagasy Hippos were hunted by humans, a likely factor in their eventual extinction.[20] Isolated members of Malagasy Hippopotamus may have survived in remote pockets; in 1976, villagers described a living animal called the Kilopilopitsofy, which may have been a Malagasy Hippopotamus.[21]

Two species of Hippopotamus, the European Hippopotamus (H. antiquus) and H. gorgops ranged throughout continental Europe and the British Isles. Both species became extinct before the last glaciation. Ancestors of European Hippos found their way to many islands of the Mediterranean during the Pleistocene.[22] Both species were larger than the modern hippopotamus, averaging about 1 meter (3.3 feet) longer. The Pleistocene also saw a number of dwarf species evolve on several Mediterranean islands including Crete (H. creutzburgi), Cyprus (H. minor), Malta (H. melitensis) and Sicily (H. pentlandi). Of these, the Cyprus Dwarf Hippopotamus, survived until the end of the Pleistocene or early Holocene. Evidence from an archaeological site Aetokremnos, continues to cause debate on whether or not the species was encountered, and was driven to extinction, by man. Hippopotamuses are among the largest living mammals; only elephants and some rhinoceroses and whales are heavier. They can live in the water or on land. Their specific gravity allows them to sink and walk or run along the bottom of a river. Hippos are considered megafauna, but unlike all other African megafauna, hippos have adapted for a semi-aquatic life in freshwater lakes and rivers.[9]:3 A hippo's lifespan is typically 40–50 years.[6]:277 Donna the Hippo, 60, was the oldest living hippo in captivity. She lived at the Mesker Park Zoo in Evansville, Indiana, USA[24][25] until her death on August 1, 2012. The oldest hippo ever recorded was called Tanga; she lived in Munich, Germany, and died in 1995 at the age of 61.[26]

Because of their enormous size, hippopotamuses are difficult to weigh in the wild. Most estimates of the weight come from culling operations that were carried out in the 1960s. The average weights for adult males ranged between 1,500–1,800 kg (3,300–4,000 lb). Females are smaller than their male counterparts, with average weights measuring between 1,300–1,500 kg (2,900–3,300 lb).[9]:12 Older males can get much larger, reaching at least 3,200 kg (7,100 lb) with a few exceptional specimens exceeding 3,600 kg (7,900 lb).[27][28] The heaviest known hippopotamus weighed approximately 4,500 kg (9,900 lb).[29] Male hippos appear to continue growing throughout their lives; females reach a maximum weight at around age 25.[30]

Hippos measure 3.3 to 5.2 meters (11 to 17 ft) long, including a tail of about 56 centimeters (22 in) in length and average about 1.5 meters (5 ft) tall at the shoulder.[31][32] The range of hippopotamus sizes overlaps with the range of the white rhinoceros; use of different metrics makes it unclear which is the largest land animal after elephants. Even though they are bulky animals, hippopotamuses can run faster than a human on land. Estimates of their running speed vary from 30 km/h (18 mph) to 40 km/h (25 mph), or even 50 km/h (30 mph). The hippo can maintain these higher speeds for only a few hundred meters. Despite being semi-aquatic and having webbed feet, an adult hippo is not a particularly good swimmer nor can it float. It is rarely found in deep water; when it is, the animal moves by porpoise-like leaps from the bottom. The eyes, ears, and nostrils of hippos are placed high on the roof of the skull. This allows them to be in the water with most of their body submerged in the waters and mud of tropical rivers to stay cool and prevent sunburn. Their skeletal structure is graviportal, adapted to carrying the animals' enormous weight. Hippopotamuses have small legs (relative to other megafauna) because the water in which they live reduces the weight burden. Unlike most other semi-aquatic animals, the hippopotamus has very little hair.[6]:260 The skin is 6 in (15 cm) thick,[33] providing it great protection against conspecifics and predators. The animals's upper parts are purplish-gray to blue-black while the under parts and areas around the eyes and ears can be brownish-pink.[6]:260 The testes of the males descend only partially and a scrotum is not present. In addition, the penis retracts into the body when not erect. The genitals of the female are unusual in that the vagina is ridged and two large diverticula protrude from the vulval vestibule. The function of these is unknown.[9]:28–29

The hippo's jaw is powered by a large masseter and a well developed digastric; the latter loops up behind the former to the hyoid.[6]:259 The jaw hinge is located far back enough to allow the animal to open its mouth at almost 180°.[9]:17 On the National Geographic Channel television program, "Dangerous Encounters with Brady Barr", Dr. Brady Barr measured the bite force of an adult female hippo at 8100 N (1821 lbf); Barr also attempted to measure the bite pressure of an adult male hippo, but had to abandon the attempt due to the male's aggressiveness.[34] Hippopotamus teeth sharpen themselves as they grind together. The lower canines and lower incisors are enlarged, especially in males, and grow continuously. The incisors can reach 40 cm (16 in) while the canines reach up to 50 cm (20 in).[33]

Their skin secretes a natural sunscreen substance which is red-colored. The secretion is sometimes referred to as "blood sweat," but is neither blood nor sweat. This secretion is initially colorless and turns red-orange within minutes, eventually becoming brown. Two distinct pigments have been identified in the secretions, one red (hipposudoric acid) and one orange (norhipposudoric acid). The two pigments are highly acidic compounds. Both pigments inhibit the growth of disease-causing bacteria; as well, the light absorption of both pigments peaks in the ultraviolet range, creating a sunscreen effect. All hippos, even those with different diets, secrete the pigments, so it does not appear that food is the source of the pigments. Instead, the animals may synthesize the pigments from precursors such as the amino acid tyrosine. Hippopotamus amphibius was widespread in North Africa and Europe during the Eemian[36] and late Pleistocene until about 30,000 years ago. The species was common in Egypt's Nile region during antiquity but has since been extirpated. Pliny the Elder writes that, in his time, the best location in Egypt for capturing this animal was in the Saite nome;[37] the animal could still be found along the Damietta branch after the Arab Conquest in 639. Hippos are still found in the rivers and lakes of the northern Democratic Republic of the Congo, Uganda, Tanzania and Kenya, north through to Ethiopia, Somalia and Sudan, west from Ghana to Gambia, and also in Southern Africa (Botswana, Republic of South Africa, Zimbabwe, Zambia, Mozambique). Genetic evidence suggests that common hippos in Africa experienced a marked population expansion during or after the Pleistocene Epoch, attributed to an increase in water bodies at the end of the era. These findings have important conservation implications as hippo populations across the continent are currently threatened by loss of access to fresh water.[10] Hippos are also subject to unregulated hunting and poaching. In May 2006 the hippopotamus was identified as a vulnerable species on the IUCN Red List drawn up by the World Conservation Union (IUCN), with an estimated population of between 125,000 and 150,000 hippos, a decline of between 7% and 20% since the IUCN's 1996 study. Zambia (40,000) and Tanzania (20,000–30,000) possess the largest populations.[1]

The hippo population declined most dramatically in the Democratic Republic of the Congo.[38] The population in Virunga National Park had dropped to 800 or 900 from around 29,000 in the mid 1970s.[39] The decline is attributed to the disruptions caused by the Second Congo War.[39] The poachers are believed to be former Hutu rebels, poorly paid Congolese soldiers, and local militia groups.[39] Reasons for poaching include the belief that hippos are harmful to society, and also for money.[40] The sale of hippo meat is illegal, but black-market sales are difficult for Virunga National Park officers to track. Invasive potential

In the late 1980s, Pablo Escobar kept four hippos in a private menagerie at his residence in Hacienda Napoles, 100 km east of Medellín, Colombia, after buying them in New Orleans. They were deemed too difficult to seize and move after Escobar's fall, and hence left on the untended estate. By 2007, the animals had multiplied to 16 and had taken to roaming the area for food in the nearby Magdalena River.[41] In 2009, two adults and one calf escaped the herd, and after attacking humans and killing cattle, one of the adults (called "Pepe") was killed by hunters under authorization of the local authorities.[42][43] It is unknown what kind of effects the presence of hippos might have on the ecosystem in Colombia. According to experts interviewed by W Radio Colombia, the animals could survive in the Colombian jungles. It is believed that the lack of control from the Colombian government, which is not used to dealing with this species, could result in human fatalities. Hippos spend most of their days wallowing in the water or the mud, with the other members of their pod. The water serves to keep their body temperature down, and to keep their skin from drying out. With the exception of eating, most of hippopotamuses' lives —from childbirth, fighting with other hippos, to reproduction— occur in the water. Hippos leave the water at dusk and travel inland, sometimes up to 8 kilometers (5 mi), to graze on short grass, their main source of food. They spend four to five hours grazing and can consume 68 kilograms (150 lb) of grass each night.[44] Like almost any herbivore, they will consume many other plants if presented with them, but their diet in nature consists almost entirely of grass, with only minimal consumption of aquatic plants.[45] Hippos have (rarely) been filmed eating carrion, usually close to the water. There are other reports of meat-eating, and even cannibalism and predation.[46] The stomach anatomy of a hippo is not suited to carnivory, and meat-eating is likely caused by aberrant behavior or nutritional stress.[9]:84

The diet of hippos consists mostly of terrestrial grasses, even though they spend most of their time in the water. Most of their defecation occurs in the water, creating allochthonous deposits of organic matter along the river beds. These deposits have an unclear ecological function.[45] Because of their size and their habit of taking the same paths to feed, hippos can have a significant impact on the land they walk across, both by keeping the land clear of vegetation and depressing the ground. Over prolonged periods hippos can divert the paths of swamps and channels.[47]

Adult hippos move at speeds up to 8 km/h (5 mph) in water. Adult hippos typically resurface to breathe every three to five minutes. The young have to breathe every two to three minutes.[9]:4 The process of surfacing and breathing is automatic, and even a hippo sleeping underwater will rise and breathe without waking. A hippo closes its nostrils when it submerges into the water. As with fish and turtles on a coral reef, hippo occasionally visit cleaning stations and signal by wide-open mouth their readiness for being cleaned of parasites by certain species of fish. This situation is an example of mutualism in which the hippo benefits from the cleansing while the fish receive food.[ Studying the interaction of male and female hippopotamuses has long been complicated by the fact that hippos are not sexually dimorphic and thus females and young males are almost indistinguishable in the field.[49] Although hippos like to lie close to each other, they do not seem to form social bonds except between mothers and daughters, and are not social animals. The reason they huddle close together is unknown.[9]:49

Hippopotamuses are territorial only in water, where a bull presides over a small stretch of river, on average 250 meters in length, and containing ten females. The largest pods can contain over 100 hippos.[9]:50 Other bachelors are allowed in a bull's stretch, as long as they behave submissively toward the bull. The territories of hippos exist to establish mating rights. Within the pods, the hippos tend to segregate by gender. Bachelors will lounge near other bachelors, females with other females, and the bull on his own. When hippos emerge from the water to graze, they do so individually.[9]:4

Hippopotamuses appear to communicate verbally, through grunts and bellows, and it is thought that they may practice echolocation, but the purpose of these vocalizations is currently unknown. Hippos have the unique ability to hold their head partially above the water and send out a cry that travels through both water and air; hippos above and under water will respond.[ Female hippos reach sexual maturity at five to six years of age and have a gestation period of 8 months. A study of endocrine systems revealed that female hippopotamuses may begin puberty as early as 3 or 4 years of age.[51] Males reach maturity at around 7.5 years. A study of hippopotamus reproductive behavior in Uganda showed that peak conceptions occurred during the end of the wet season in the summer, and peak births occurred toward the beginning of the wet season in late winter. This is because of the female's estrous cycle; as with most large mammals, male hippopotamus spermatozoa is active year round. Studies of hippos in Zambia and South Africa also showed evidence of births occurring at the start of the wet season.[9]:60–61 After becoming pregnant, a female hippopotamus will typically not begin ovulation again for 17 months.[51]

Mating occurs in the water with the female submerged for most of the encounter,[9]:63 her head emerging periodically to draw breath. Baby hippos are born underwater at a weight between 25 and 45 kg (60–110 lb) and an average length of around 127 cm (50 in) and must swim to the surface to take their first breath. A mother typically gives birth to only one hippo, although twins also occur. The young often rest on their mothers' backs when in water that is too deep for them, and they swim underwater to suckle. They also will suckle on land when the mother leaves the water. Weaning starts between six and eight months after birth and most calves are fully weaned after a year.[9]:64 Like many other large mammals, hippos are described as K-strategists, in this case typically producing just one large, well-developed infant every couple of years (rather than large numbers of small, poorly developed young several times per year as is common among small mammals such as rodents. Hippopotamuses are by nature very aggressive animals, especially when young calves are present. Frequent targets of their aggression include crocodiles, which often inhabit the same river habitat as hippos. Nile crocodiles, lions and spotted hyenas are known to prey on young hippos.[53] Hippos are very aggressive towards humans, whom they commonly attack whether in boats or on land with no apparent provocation.[54] They are widely considered to be one of the most dangerous large animals in Africa.[55][56]

To mark territory, hippos spin their tails while defecating to distribute their excrement over a greater area.[57] Likely for the same reason, hippos are retromingent – that is, they urinate backwards.[58] When in combat, male hippos use their incisors to block each others attacks, and their lower canines to inflict damage.[6]:260 Hippos rarely kill each other, even in territorial challenges. Usually a territorial bull and a challenging bachelor will stop fighting when it is clear that one hippo is stronger. When hippos become overpopulated, or when a habitat starts to shrink, bulls will sometimes attempt to kill infants, but this behavior is not common under normal conditions.[52] Some incidents of hippo cannibalism have been documented, but it is believed to be the behavior of distressed or sick hippos, and not healthy behavior. The earliest evidence of human interaction with hippos comes from butchery cut marks upon hippo bones at Bouri Formation dated around 160,000 years ago.[59] Later rock paintings and engravings showing hippos being hunted have been found in the mountains of the central Sahara dated 4,000–5,000 years ago near Djanet in the Tassili n'Ajjer Mountains.[9]:1 The ancient Egyptians recognized the hippo as a ferocious denizen of the Nile.

The hippopotamus was also known to the Greeks and Romans. The Greek historian Herodotus described the hippopotamus in The Histories (written circa 440 BC) and the Roman Historian Pliny the Elder wrote about the hippopotamus in his encyclopedia Naturalis Historia (written circa 77 AD).[37][60] Hippopotamus was one of the many exotic animals brought to fight gladiators in Rome by the emperor Philip I the Arab to commemorate Rome's 1000 years anniversary in 248 AD. Silver coins with hippo's image were minted that year.[citation needed]

Zulu warriors preferred to be as brave as a hippopotamus, since even lions were not considered as brave. "In 1888, Captain Baden-Powell was part of a column searching for the Zulu chief Dinizulu, who was leading the Usutu people in revolt against the British colonists. The column was joined by John Dunn, a white Zulu chief, who led an impi (army) of 2000 Zulu warriors to join the British." [61]

The words of the Zulu anthem sounded like this:

"Een-gonyama Gonyama! "Invooboo! Yah-bo! Yah-bo! Invooboo!"

"John Dunn was at the head of his impi. [Baden Powell] asked him to translate the Zulu anthem his men had been singing. Dunn laughed and replied: "He is a lion. Yes, he is better than a lion—he is a hippopotamus. Hippopotamuses have long been popular zoo animals. The first zoo hippo in modern history was Obaysch who arrived at the London Zoo on May 25, 1850, where he attracted up to 10,000 visitors a day and inspired a popular song, the Hippopotamus Polka.[63] Hippos have remained popular zoo animals since Obaysch, and generally breed well in captivity. Their birth rates are lower than in the wild, but this is attributed to zoos' not wanting to breed as many hippos as possible, since hippos are large and relatively expensive animals to maintain.[9]:129[63]

Like many zoo animals, hippos were traditionally displayed in concrete exhibits. In the case of hippos, they usually had a pool of water and patch of grass. In the 1980s, zoo designers increasingly designed exhibits that reflected the animals' native habitats. The best known of these, the Toledo Zoo Hippoquarium, features a 360,000 gallon pool for hippos.[64] In 1987, researchers were able to tape, for the first time, an underwater birth (as in the wild) at the Toledo Zoo. The exhibit was so popular that the hippos became the logo of the Toledo Zoo. A red hippo represented the Ancient Egyptian god Set; the thigh is the 'phallic leg of set' symbolic of virility. Set's consort Tawaret was also seen as part hippo.[66] The hippopotamus-headed Tawaret was a goddess of protection in pregnancy and childbirth, because ancient Egyptians recognized the protective nature of a female hippopotamus toward her young.[67] The Ijo people wore masks of aquatic animals like the hippo when practicing their water spirit cults.[68] The Behemoth from the Book of Job, 40:15–24 is also thought to be based on a hippo.[69]

Hippos have been the subjects of various African folktales. According to a Bushmen story; when the Creator assigned each animal their place in nature, the hippos wanted to live in the water, but were refused out of fear that they might eat all the fish. After begging and pleading, the hippos were finally allowed to live in the water on the conditions that they would eat grass instead of fish and would fling their dung so that it can be inspected for fish bones.[70] In a Ndebele tale, the hippo originally had long, beautiful hair but was set on fire by a jealous hare and had to jump into a nearby pool. The hippo lost most of his hair and was too embarrassed to leave the water.[70]

Ever since Obaysch inspired the Hippopotamus Polka, hippos have been popular animals in Western culture for their rotund appearance that many consider comical.[63] Stories of hippos like Huberta who became a celebrity in South Africa in the 1930s for trekking across the country;[71] or the tale of Owen and Mzee, a hippo and tortoise who developed an intimate bond; have amused people who have bought hippo books, merchandise, and many a stuffed hippo toy.[72][73] Hippos were mentioned in the novelty Christmas song "I Want a Hippopotamus for Christmas" that became a hit for child star Gayla Peevey in 1953.[74] They also feature in the songs "The Hippopotamus" and "Hippo Encore" by Flanders and Swann, with the famous refrain Mud, Mud, Glorious Mud. They even inspired a popular board game, Hungry Hungry Hippos. Hippos have also been popular cartoon characters, where their rotund frame is used for humorous effect. The Disney film Fantasia featured a ballerina hippopotamus dancing to the opera, La Gioconda.[38] Other cartoon hippos have included Hanna-Barbera's Peter Potamus, the book and TV series George and Martha, Flavio and Marita on the Animaniacs, Pat of the French duo Pat et Stanley, The Backyardigan's Tasha, and Gloria and Moto-Moto from the Madagascar franchise. A Sesame Street cartoon from the early 1970s features a hippo who lives in the country and likes it quiet, while being disturbed when the mouse who likes it loud moves in with her.[citation needed]

The hippopotamus characters "Happy Hippos" were created in 1988 by the French designer Andre Roche [77] based in Munich, to be hidden in the "Kinder Surprise egg" of the Italian chocolate company Ferrero SpA. These characters were not placid like real hippos[contradiction] but rather cute and lively, and had such a success that they reappeared several times in different products of this company in the following years, increasing their popularity worldwide each time.[citation needed] The Nintendo Company published in the years 2001 and 2007 Game Boy adventures of them. In the game of chess, the hippopotamus lends its name to the Hippopotamus Defense, an opening system, which is generally considered weak.The River Horse is a popular outdoor sculpture at George Washington University, Washington, D.C. Botswana, Moremi National Park, Moremi Game reserve, private Reserve, Farm, chobe National park, Chobe Game Reserve, Zambia, Zambezi River, Livingstone, Zimbabwe, Kenya, Tanzania, Wildlife Conservation Project, Maramba River Lodge, South Africa, Krugger National Park. art beach blue bw california canada canon china city concert de england europe family festival film flower flowers food france friends green instagramapp iphoneography italy japan live london music nature new newyork night nikon nyc paris park party people photography portrait red sky snow square squareformat street summer sunset travel trip uk usa vacation water wedding white winter

Sitting there ouside the Hospital in Brilliant Spring Sunshine, Gordon had trouble keeping his eyes open Lol! Hugs Gordon & Terry

 

This image depicts original artwork proofs for J. P. Chu's c.1938 publication in the Transactions of the Royal Society of Edinburgh. At this time he was studying at the Institute of Animal Genetics and his research focused on changes in the pigmentation of plumage in related to endocrine function. He attended the University on a two year scholarship in physiology.

J.P. Chu (Renbao Zhu) was born 8 February 1909 in Zhejiang Jinhua Ling Xia Zhu, China. During his youth Chu experienced poverty and a turbulent political atmosphere caused by Japanese invasions. Chu left home at a young age to study in Jinhua, and after graduation was admitted to the Department of psychology at Zhejiang University. In 1931 he moved to Nanjing Centre College and graduated from university in 1962. From 1932 to 1936 he worked as an assistant to the biology department at Zhejaing University.

From 1936-1938 Chu attended the University of Edinburgh to study physiology at the Institute of Animal Genetics. In 1938 Chu moved to Hampstead, London, to study at the National Institute of Medical Research with Dr. A. S. Parkes. He was awarded a PhD in from the University of Edinburgh, and returned to China in 1940 to take the post of Professor of Animal Husbandry at Nanking University. During his time in the UK Chu focused his studies on glandular functions in Leghorn Fowl and after returning to China went on to research in various areas including anti-radiation, shock prevention, grafting, and stem cells. He held a fellowship at the Military Medical Science Academy, and was later to become the Director of the Institute of Radiation Medicine at the same institute. Chu published over 100 articles and died 24 October 1987.

The full LUNA record for this item is here: images.is.ed.ac.uk/luna/servlet/detail/UoEgal~4~4~48217~1...

© The University of Edinburgh Library

The impact of chemicals on children’s brain development: a cause for concern and a need for action

 

Science has shown that many thousands of people have been exposed to now mostly banned chemicals such as lead and PCBs at high enough levels to have had their brain development negatively affected. This report finds that there are other chemicals which are still in routine use in our homes where there is evidence of similar developmental neurotoxic (DNT) properties, and also identifies huge gaps in our knowledge of the impacts of other chemicals on brain development. It also points out the unpleasant reality that we are constantly exposed to a cocktail of chemicals, something which is still largely ignored by chemical safety laws.

 

In spite of the lessons of the past, regulators are continuing to only regulate after harm is caused, instead of acting to effectively protect the most precious of things; children’s developing brains.

 

In June 2007 CHEM Trust wrote the briefing Chemicals Compromising Our Children, which highlighted growing concerns about the impacts of chemicals on brain development in children. Almost 10 years later, CHEM Trust has revisited the issue with this report, which includes contributions from two of the most eminent scientists in this area, Professor Barbara Demeneix (Laboratory of Evolution of Endocrine Regulations, CNRS, Paris) and Professor Philippe Grandjean (Department of Environmental Medicine, University of Southern Denmark, Denmark & Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, USA), who also peer reviewed the report.

 

Our brain and its development

 

Our brains are astoundingly complex, made up of over 85 billion neurons, which have grown, developed and interconnected during our lives. The brain is the organ that takes the longest to develop, with initial stages of cell division, creation of neurons and their migration taking place from the first hours after fertilisation and throughout the foetus’ time in the womb. However, brain development does not stop at birth – it’s not until our twenties that neurons are fully developed with their myelin coats.

 

Throughout this complex developmental process a range of signalling chemicals and other processes operate in order to control what happens. The thyroid hormone system is intimately involved in brain development and function, yet it is well established that this system can be disrupted – for example by a lack of iodine (essential to make thyroid hormone) or by certain chemicals. If developmental processes are disrupted, this most often creates permanent problems.

 

The complexity of brain development and function means that deficits can be very subtle – small reductions in IQ, disabilities that exist with a broad spectrum of seriousness such as autism, or in some cases conditions which do not have fully agreed diagnostic criteria.

 

Disruption of brain development by chemicals

 

We are all exposed to hundreds of man-made chemicals in our daily life, coming from everyday products including food, furniture, packaging and clothes. Many of these chemicals will have no negative effects on us, but it is now well established that some are able to disrupt normal development of the brain. Chemicals with long established DNT properties such as lead, PCBs and methylmercury, have been joined by others where DNT effects have been identified more recently, and which are being used in everyday products. There are also rising concerns about chemicals that are very similar to chemicals that have had their use restricted, but which we continue to use as there isn’t sufficient information about their toxic effects. We know even less about thousands of other chemicals in routine use, which have had no testing for DNT properties.

 

Chemical exposures are so ubiquitous that experts have recognized that babies are born “pre-polluted”. Scientific paediatric and gynaecology & obstetrics societies have consistently warned about chronic health implications from both acute and chronic exposure to chemicals such as pesticides and endocrine disruptors.

 

The report identifies evidence of DNT properties for the following chemicals:

 

- Bisphenol A (BPA)

a chemical that was used to make baby bottles, is currently being phased out of till receipts (in the EU), but is still used in the making of food can linings and many polycarbonate plastics. There are also concerns about closely related chemicals that are not restricted, including Bisphenol S.

- Brominated Flame Retardants (BFRs)

a group of chemicals added to furniture, electronics and building materials. The evidence for neurodevelopmental effects is strongest for the PBDE (polybrominated diphenyl ether) group of BFRs, which are already banned or nearly banned in the EU, though they are still in furniture in our homes, and in dust. However, other BFRs are now being found in dust and human blood serum, with concerns that these BFRs might have similar effects.

- Phthalates

a group of chemicals used as plasticisers in PVC and in other products. Some chemicals in this group are now banned in the EU, but many others are still in use.

- Per- and poly-fluorocarbons (PFCs)

used as non-stick coatings or breathable coatings, are a large group of chemicals, a few of which are in the process of being restricted by the EU. There is evidence that some PFCs can disrupt the action of the thyroid hormone. PFCs are very persistent in the environment, and many of them can accumulate in our bodies – they are routinely found in blood.

- Perchlorate

a contaminant of food, related to the use of certain fertilisers and hypochlorite bleach, and is known to disrupt the thyroid hormone system.

 

Are we protected?

 

The EU has the most sophisticated regulations in the world for controlling chemical use. However, there are a number of key flaws in this system:

 

- There is often inadequate safety information about individual chemicals, including a lack of information about neurodevelopmental effects.

- The processes to ban chemicals are too slow, and the restrictions created often have big loopholes as a result of industry lobbying.

- Chemicals are addressed one at a time, so one chemical may have its use restricted, but closely related chemicals remain in use.

- We are always exposed to multiple chemicals, but regulations almost always assume we are only exposed to one at a time, even though numerous scientists have shown that chemical effects can add together in our bodies.

 

Policy recommendations

 

It is clear that our children are not currently being protected from chemicals that can disrupt brain development. We have identified a range of policy measures that could improve the situation, including:

 

- Acting faster to ban chemicals of concern, including addressing groups of similar substances, not just those where we have the most information.

- Ensuring that any safety testing of chemicals includes evaluation of DNT effects.

- Ensuring better identification and regulation of neurodevelopmental toxic chemicals.

- Ensuring that all uses of chemicals are properly regulated; for example there is a lack of effective regulation of chemicals in food packaging including paper, card, inks, glues and coatings.

- The UK and Ireland should remove the requirement for an open flame test for furniture. This test is not required in the rest of the EU, and leads to increased use of flame retardant chemicals.

 

Finally, it is important to note that EU regulations have already controlled a number of chemicals of concern, and that EU laws provide a tool to address these problems. We therefore think it is vital for the UK Government to work to stay aligned with EU chemicals laws, whatever the eventual outcome of the UK’s Brexit process.

 

Though full protection will only come from proper regulation of chemicals, the report also includes a chapter with tips for reducing your and your family’s exposures in daily life.

 

Sources and More Information

- Download the full report, No Brainer The impact of chemicals on children’s brain development: a cause for concern and a need for action, chemtrust, 2017.

- IT’S A NO BRAINER! Action needed to stop children being exposed to chemicals that harm their brain development!, chemtrust, MARCH 7, 2017.

Encapsulated Pro-Islet™ graft containing pancreatic endocrine cells. In these images, blue represents insulin, red is glucagon, and green is somatostatin.

 

Pancreatic progenitor cells made from human embryonic stem cells in vitro are loaded into encapsulation device before transplantation. Cells mature into the different pancreatic endocrine cells, including importantly, insulin-expressing beta cells. These cells produce insulin in response to glucose, effectively replacing the insulin that is lost in people with type 1 diabetes. ViaCyte has several CIRM grants to develop a stem cell-based therapy for type 1 diabetes based on this work.

 

Image taken by Kuniko Kadoya, PhD at Viacyte, Inc.

Labeled as only 15 grams of carbohydrate, toast is 60% carbs as opposed to 40% when it's bread which takes longer to digest. Toast spiked my blood sugar to 132 mg/dl which is more than ice cream at 105 mg/dl, but not as much as cooked steel cut oatmeal which tops all my readings at 155 mg/dl. (Normal is 85.) Why is this bad?

 

Here is the science as I have gleaned from my reading of "Good Calories, Bad Calories". I had to read parts of the book several times to keep from glossing over the technical details, but once I read slowly enough to visualize what each component of the metabolic system did, it became easier to understand.

 

So to begin, most food breaks down in the blood stream and becomes sugar. Sugar is already sugar so jumps right in there. Carbohydrates, especially refined, cooked carbs also turn to sugar very fast. Too much sugar in the blood registers as high blood sugar. High blood sugars are toxic to the body, wreaking havoc on kidneys and other organs.

 

The normal body takes care of these spikes from food by releasing insulin from the pancreas, which allows the blood sugars to be absorbed by various parts of the body i.e. muscle tissue, thus taking it out of the blood stream and converting it to fuel for the body. This is how the body regulates itself to survive during periods of no food whether for a few hours, or weeks, or months. Too much insulin and the body becomes insulin resistant; first the muscle tissue refuses to take in the sugars, so it goes to the fat tissue where it is stored indefinitely as fat.

 

A handful of hormones allows the energy stored as fat to be disassembled into fatty acids that go back into the blood stream where it can be used as fuel by other parts of the body. If there is too much insulin in the body, the hormones aren't able to facilitate this transference and the fat stays locked down in the adipose tissue. (Note to my fellow organizers: one study showed that rats that had had their ovaries removed and thus were estrogen deprived, ate voraciously and stored food in their cages. Infusing estrogen back into these rats suppressed the food-hoarding. Sounds like something hoarding researchers should look into. See p. 373.)

 

It is possible to release fat from your body by starving yourself thus engaging one of the survival mechanisms of our bodies; this will make you hungry which is why restricting food (going on a diet) is rarely maintained and can cause psychological disorders such as depression. As food intake drops, thyroid hormone falls and metabolic rate is lowered. The starvation diet is telling the body there isn't any food out there so stay quiet, hibernate. The longer this goes on, the more efficient the body gets at using fat sparingly.

 

Once the fuel is used up the body will want to replenish the lost reserves right away, at first. Being hungry serves the purpose of alerting us to find more food. The body can release fat with hard labor, but will do this sparingly, i.e., more slowly than when it made the fat in the first place, in case food supplies are really low. No food is better than a tiny morsel as far as satisfying hunger. No food tells the body to lie low, stay peaceful, maybe even die.

 

So calorie restriction and exercise is the hardest way to lose weight and may make you irritable on top of it. Which is why it's so pathologically entertaining to watch all those fat people struggling on "The Biggest Loser". What the show doesn't dwell on is that the participants are eating a comparatively high fat, low carb diet with no sodas permitted (no sandwiches, no cereals, half a tortilla, carbs mostly in veggies, etc), which would allow them to lose weight anyway. In fact it would probably be easier on them to lose much of the weight before undergoing the heart endangering marathon exercise regime, but of course, not as good TV. And thus that warning at the end about checking with your doctor before attempting this at home.

 

The easy way to lose weight is to eat fatty foods to satisfy appetite and restrict easily digestible carbs like toast, oatmeal, mashed potatoes, white rice, pasta—especially overcooked pasta and most of all anything with high fructose corn syrup. That stuff has a special feature; it doesn't affect blood sugar so it gives the appearance of being healthier on the glycemic index, but the kicker is that it goes straight to the liver which converts the fructose directly to fat molecules—triglycerides to be precise. That which your doctor may point to, on your blood work, as heading into cardiac arrest territory.

 

Most of my peeps know to avoid sodas, but we have not yet learned about the carbohydrates, drives insulin, drives fat equation. At least I had not because I never had to care about weight loss. My problem seems to be more about the insulin resistance not allowing the muscles to build up and the fat tissues becoming insulin resistant before I could lay down any fat; this seems more typical of Type 1 diabetes. Practically speaking my blood sugars were perpetually high and I'm hypoglycemic after eating 3 Ritz crackers, knocked out as though hit by a drug.

 

But high blood sugars is not just about training the body to become diabetic or obese. It also weighs in on other health issues because everyone can be affected by levels of insulin and possibly become insulin resistant.

 

Hypertension for one. Here's another one of those medical establishment myths debunked. No evidence has shown that eating salt results in salt in the blood, or only slightly for a short time. Reducing salt in your diet has only a marginal effect on salt in the body. However a carbohydrate rich diet prompts the kidneys to hold onto salt, rather than excrete it. The body retains water to keep the sodium concentrate constant which causes blood pressure to go up. So if you want to get off those antihypertensive drugs (a diuretic to make you pee both salt and water out) try reducing carb intake.

 

Heart disease: Once carbs flood the blood stream with glucose, the liver picks up some of it and transforms it into fat. This fat boat, called a triglyceride, floats around the body delivering bits of fat and shrinking as fat is dropped off. The more carbohydrates, the bigger and lighter and longer living the triglyceride boat which then becomes the small, dense artherogenic (plaque making) LDL—the bad cholesterol. If no carbs eaten, then smaller and heavier boat that ends up as large, fluffy benign LDL. Since these LDL twins are seen as one, triglyceride counts are a better indicator of heart disease.

 

As for Alzheimer patients. A healthy brain clears away amyloid proteins (which are made when a certain larger protein is split), but an insulin-filled brain is occupied with clearing out insulin and cannot also clear out amyloid proteins. It is these proteins that combine with glucose to form plaques called amyloid-plaque accumulation (AGEs) and that accumulation causes vascular damage in the brain.

 

And cancer. Fat does not cause cancer and being fat does not cause cancer, rather getting fat may be a result of cancer activity. Glucose intolerance seems to play a part in cancer. Cancerous cells are mutations that occur all the time when new cells are made, but they only become tumors once they can grow and they only grow in the presence of insulin. Cancer cells have more receptors for insulin which allows it to feed more readily on blood sugars than other cells which become insulin resistant over a short time. Cancer cells burn perhaps 30x more sugar than normal cells. Thus the "sugar feeds cancer" premise I've been hearing about. But no one mentioned carbs turning into sugar so quickly so I didn't make the connection. Researches did not see the need to take into account that carbs were easily made into sugar because they were biased by the fat-leads-to-cholesterol theory so thought carbs were irrelevant.

  

(A note about environmental toxins was made in reference to a researcher attributing the causes of disease to external circumstances. He meant eating and lifestyle habits, but the public took it as an affirmation that the "toxic soup" we live in is a danger to us; scientists responded to this misinterpretation saying that there was no actual evidence for toxins causing disease. I believe we are subject to toxic impact as far as endocrine interrupters and birth defects, but that is not about disease.)

 

And tooth decay. Sugar intake parallels carb intake in baked goods, cereals, crackers, etc. So dental problems parallel these other diseases of civilization.

 

Longevity. The hypothesis is that he who has the most free radicals (caused by oxidation generated by cells burning fuel), is bogged down by glycation—the binding of sugars to proteins in a haphazard, plastic-in-the-ocean kind of way, attracting toxic sequelae—big word for stuff that causes infection. You can reduce free radicals by half starving yourself and burning less fuel, a strategy my 95 lb, super-active mother seems to have employed. However, reduced blood sugar and thus reduced insulin resistance leads to reduced oxidative stress and decrease in glycation. Researchers are also making a connection between insulin activity and a doubling of life span triggered by a mutation too complex for me to grok, but is about organisms waiting out a bad spell in food supply in order to stay young enough to reproduce when there is food available.

 

This whole story about the bodies ability to survive is not quite as romantic and action packed as the increasingly popular Paleo diet story about hunters constantly having to run down game (and then gorging on meat). From descriptions recorded by early naturalists, when there was game, it was there in such abundance that it had to be cleared away like so much underbrush by settlers trying to proceed. Running a lot and shooting off your bow and arrow makes good The Hunger Games, but is hard on your joints and may cause carpel tunnel syndrome. Better that the humans be walking together in community, from food source to food source setting traps and when the going gets tough, hunkering down in caves together communing with spirits. Life alternating between mobile mardi gras and Shamanic sheltering in place.

 

With agriculture came the enslavement of most humans to till the land, thus enabling some humans to develop civilization as we know it in all its material glory. Chronic disease may be the price we pay especially if we stick with conventional wisdom.

Freshly pressed: horsetail, stinging nettles, cleavers and wheatgrass for our spring cleanse!

 

The younger daughter, the bravest of all of us, drank it without making a face. Mom was the second bravest... the rest of us followed...

 

Horsetail (Equisetum arvense) is one of the most diuretic plants. It is also effective in removing lead accumulations in the body. It contains silica. Silica helps to fix calcium, so that the body can store more of it and then use it to repair bones, collagen and other body tissues. It is also recommended for anemia and to treat deep-seated lung damage, inflammation or benign enlargement of the prostate gland and the removal of kidney stones. Its toning and astringent action make it of value in the treatment of incontinence and bed-wetting in children.

 

Stinging nettles (Urtica dioica) are the best blood purifier available and have an influence over the pancreas. Stinging nettles also assist in lowering blood sugar, treat anemia, arthritis and rheumatism, respiratory and urinary problems, eczema, asthma, sinusitis and rhinitis, enlarged prostate, protect against hair loss, kidney stones, allergies, hay fever, osteoarthritis, internal bleeding, uterine bleeding, nosebleeds and bowel bleeding, protect against enlarged spleen, diabetes, endocrine disorders, stomach acid, diarrhea, dysentery, lung congestion, cancer, wound healing.

 

Cleavers (Galium aparine) promotes lymphatic flow and lymphatic drainage of toxins and wastes so that they can be excreted via the urinary system. It is also excellent for skin problems, including eczema, psoriasis, acne, boils, abscesses, urinary infections. urinary stones and gravel, arthritis and gout. It has anti-tumor activity, particularly when in the skin or breasts, and the lymphatic system.

  

Wheatgrass is used for removing deposits of heavy metals, and cancer-causing agents from the body and for removing toxins from the liver and blood. It is also used for increasing production of hemoglobin, improving blood sugar disorders, preventing tooth decay; improving wound healing; and preventing bacterial infections. Wheatgrass helps in treatment of urinary tract and prostate, gout; liver; ulcerative colitis; joint pain; and chronic skin problems, cancer and arthritis.

Muladara

 

Element: earth

   

This is my chakra project, It was a journey which taught me about myself and others. The simple images represent first a merge between the conscious and the subconscious and explores the physical connection of that hyperconscious with the human body (through the endocrine system and nervous system) and our physical surroundings. Each chakra corresponds to an element and a glad within the endocrine system/a part of the body where the energy of that chakra resides in a swirl of energy.

 

Fish, any of approximately 34,000 species of vertebrate animals (phylum Chordata) found in the fresh and salt waters of the world. Living species range from the primitive jawless lampreys and hagfishes through the cartilaginous sharks, skates, and rays to the abundant and diverse bony fishes. Most fish species are cold-blooded; however, one species, the opah (Lampris guttatus), is warm-blooded.

 

The term fish is applied to a variety of vertebrates of several evolutionary lines. It describes a life-form rather than a taxonomic group. As members of the phylum Chordata, fish share certain features with other vertebrates. These features are gill slits at some point in the life cycle, a notochord, or skeletal supporting rod, a dorsal hollow nerve cord, and a tail. Living fishes represent some five classes, which are as distinct from one another as are the four classes of familiar air-breathing animals—amphibians, reptiles, birds, and mammals. For example, the jawless fishes (Agnatha) have gills in pouches and lack limb girdles. Extant agnathans are the lampreys and the hagfishes. As the name implies, the skeletons of fishes of the class Chondrichthyes (from chondr, “cartilage,” and ichthyes, “fish”) are made entirely of cartilage. Modern fish of this class lack a swim bladder, and their scales and teeth are made up of the same placoid material. Sharks, skates, and rays are examples of cartilaginous fishes. The bony fishes are by far the largest class. Examples range from the tiny seahorse to the 450-kg (1,000-pound) blue marlin, from the flattened soles and flounders to the boxy puffers and ocean sunfishes. Unlike the scales of the cartilaginous fishes, those of bony fishes, when present, grow throughout life and are made up of thin overlapping plates of bone. Bony fishes also have an operculum that covers the gill slits.

 

The study of fishes, the science of ichthyology, is of broad importance. Fishes are of interest to humans for many reasons, the most important being their relationship with and dependence on the environment. A more obvious reason for interest in fishes is their role as a moderate but important part of the world’s food supply. This resource, once thought unlimited, is now realized to be finite and in delicate balance with the biological, chemical, and physical factors of the aquatic environment. Overfishing, pollution, and alteration of the environment are the chief enemies of proper fisheries management, both in fresh waters and in the ocean. (For a detailed discussion of the technology and economics of fisheries, see commercial fishing.) Another practical reason for studying fishes is their use in disease control. As predators on mosquito larvae, they help curb malaria and other mosquito-borne diseases.

 

Fishes are valuable laboratory animals in many aspects of medical and biological research. For example, the readiness of many fishes to acclimate to captivity has allowed biologists to study behaviour, physiology, and even ecology under relatively natural conditions. Fishes have been especially important in the study of animal behaviour, where research on fishes has provided a broad base for the understanding of the more flexible behaviour of the higher vertebrates. The zebra fish is used as a model in studies of gene expression.

 

There are aesthetic and recreational reasons for an interest in fishes. Millions of people keep live fishes in home aquariums for the simple pleasure of observing the beauty and behaviour of animals otherwise unfamiliar to them. Aquarium fishes provide a personal challenge to many aquarists, allowing them to test their ability to keep a small section of the natural environment in their homes. Sportfishing is another way of enjoying the natural environment, also indulged in by millions of people every year. Interest in aquarium fishes and sportfishing supports multimillion-dollar industries throughout the world.

 

Fishes have been in existence for more than 450 million years, during which time they have evolved repeatedly to fit into almost every conceivable type of aquatic habitat. In a sense, land vertebrates are simply highly modified fishes: when fishes colonized the land habitat, they became tetrapod (four-legged) land vertebrates. The popular conception of a fish as a slippery, streamlined aquatic animal that possesses fins and breathes by gills applies to many fishes, but far more fishes deviate from that conception than conform to it. For example, the body is elongate in many forms and greatly shortened in others; the body is flattened in some (principally in bottom-dwelling fishes) and laterally compressed in many others; the fins may be elaborately extended, forming intricate shapes, or they may be reduced or even lost; and the positions of the mouth, eyes, nostrils, and gill openings vary widely. Air breathers have appeared in several evolutionary lines.

 

Many fishes are cryptically coloured and shaped, closely matching their respective environments; others are among the most brilliantly coloured of all organisms, with a wide range of hues, often of striking intensity, on a single individual. The brilliance of pigments may be enhanced by the surface structure of the fish, so that it almost seems to glow. A number of unrelated fishes have actual light-producing organs. Many fishes are able to alter their coloration—some for the purpose of camouflage, others for the enhancement of behavioral signals.

 

Fishes range in adult length from less than 10 mm (0.4 inch) to more than 20 metres (60 feet) and in weight from about 1.5 grams (less than 0.06 ounce) to many thousands of kilograms. Some live in shallow thermal springs at temperatures slightly above 42 °C (100 °F), others in cold Arctic seas a few degrees below 0 °C (32 °F) or in cold deep waters more than 4,000 metres (13,100 feet) beneath the ocean surface. The structural and, especially, the physiological adaptations for life at such extremes are relatively poorly known and provide the scientifically curious with great incentive for study.

 

Almost all natural bodies of water bear fish life, the exceptions being very hot thermal ponds and extremely salt-alkaline lakes, such as the Dead Sea in Asia and the Great Salt Lake in North America. The present distribution of fishes is a result of the geological history and development of Earth as well as the ability of fishes to undergo evolutionary change and to adapt to the available habitats. Fishes may be seen to be distributed according to habitat and according to geographical area. Major habitat differences are marine and freshwater. For the most part, the fishes in a marine habitat differ from those in a freshwater habitat, even in adjacent areas, but some, such as the salmon, migrate from one to the other. The freshwater habitats may be seen to be of many kinds. Fishes found in mountain torrents, Arctic lakes, tropical lakes, temperate streams, and tropical rivers will all differ from each other, both in obvious gross structure and in physiological attributes. Even in closely adjacent habitats where, for example, a tropical mountain torrent enters a lowland stream, the fish fauna will differ. The marine habitats can be divided into deep ocean floors (benthic), mid-water oceanic (bathypelagic), surface oceanic (pelagic), rocky coast, sandy coast, muddy shores, bays, estuaries, and others. Also, for example, rocky coastal shores in tropical and temperate regions will have different fish faunas, even when such habitats occur along the same coastline.

 

Although much is known about the present geographical distribution of fishes, far less is known about how that distribution came about. Many parts of the fish fauna of the fresh waters of North America and Eurasia are related and undoubtedly have a common origin. The faunas of Africa and South America are related, extremely old, and probably an expression of the drifting apart of the two continents. The fauna of southern Asia is related to that of Central Asia, and some of it appears to have entered Africa. The extremely large shore-fish faunas of the Indian and tropical Pacific oceans comprise a related complex, but the tropical shore fauna of the Atlantic, although containing Indo-Pacific components, is relatively limited and probably younger. The Arctic and Antarctic marine faunas are quite different from each other. The shore fauna of the North Pacific is quite distinct, and that of the North Atlantic more limited and probably younger. Pelagic oceanic fishes, especially those in deep waters, are similar the world over, showing little geographical isolation in terms of family groups. The deep oceanic habitat is very much the same throughout the world, but species differences do exist, showing geographical areas determined by oceanic currents and water masses.

 

All aspects of the life of a fish are closely correlated with adaptation to the total environment, physical, chemical, and biological. In studies, all the interdependent aspects of fish, such as behaviour, locomotion, reproduction, and physical and physiological characteristics, must be taken into account.

 

Correlated with their adaptation to an extremely wide variety of habitats is the extremely wide variety of life cycles that fishes display. The great majority hatch from relatively small eggs a few days to several weeks or more after the eggs are scattered in the water. Newly hatched young are still partially undeveloped and are called larvae until body structures such as fins, skeleton, and some organs are fully formed. Larval life is often very short, usually less than a few weeks, but it can be very long, some lampreys continuing as larvae for at least five years. Young and larval fishes, before reaching sexual maturity, must grow considerably, and their small size and other factors often dictate that they live in a habitat different than that of the adults. For example, most tropical marine shore fishes have pelagic larvae. Larval food also is different, and larval fishes often live in shallow waters, where they may be less exposed to predators.

 

After a fish reaches adult size, the length of its life is subject to many factors, such as innate rates of aging, predation pressure, and the nature of the local climate. The longevity of a species in the protected environment of an aquarium may have nothing to do with how long members of that species live in the wild. Many small fishes live only one to three years at the most. In some species, however, individuals may live as long as 10 or 20 or even 100 years.

 

Fish behaviour is a complicated and varied subject. As in almost all animals with a central nervous system, the nature of a response of an individual fish to stimuli from its environment depends upon the inherited characteristics of its nervous system, on what it has learned from past experience, and on the nature of the stimuli. Compared with the variety of human responses, however, that of a fish is stereotyped, not subject to much modification by “thought” or learning, and investigators must guard against anthropomorphic interpretations of fish behaviour.

 

Fishes perceive the world around them by the usual senses of sight, smell, hearing, touch, and taste and by special lateral line water-current detectors. In the few fishes that generate electric fields, a process that might best be called electrolocation aids in perception. One or another of these senses often is emphasized at the expense of others, depending upon the fish’s other adaptations. In fishes with large eyes, the sense of smell may be reduced; others, with small eyes, hunt and feed primarily by smell (such as some eels).

 

Specialized behaviour is primarily concerned with the three most important activities in the fish’s life: feeding, reproduction, and escape from enemies. Schooling behaviour of sardines on the high seas, for instance, is largely a protective device to avoid enemies, but it is also associated with and modified by their breeding and feeding requirements. Predatory fishes are often solitary, lying in wait to dart suddenly after their prey, a kind of locomotion impossible for beaked parrot fishes, which feed on coral, swimming in small groups from one coral head to the next. In addition, some predatory fishes that inhabit pelagic environments, such as tunas, often school.

 

Sleep in fishes, all of which lack true eyelids, consists of a seemingly listless state in which the fish maintains its balance but moves slowly. If attacked or disturbed, most can dart away. A few kinds of fishes lie on the bottom to sleep. Most catfishes, some loaches, and some eels and electric fishes are strictly nocturnal, being active and hunting for food during the night and retiring during the day to holes, thick vegetation, or other protective parts of the environment.

 

Communication between members of a species or between members of two or more species often is extremely important, especially in breeding behaviour (see below Reproduction). The mode of communication may be visual, as between the small so-called cleaner fish and a large fish of a very different species. The larger fish often allows the cleaner to enter its mouth to remove gill parasites. The cleaner is recognized by its distinctive colour and actions and therefore is not eaten, even if the larger fish is normally a predator. Communication is often chemical, signals being sent by specific chemicals called pheromones.

 

Many fishes have a streamlined body and swim freely in open water. Fish locomotion is closely correlated with habitat and ecological niche (the general position of the animal to its environment).

 

Many fishes in both marine and fresh waters swim at the surface and have mouths adapted to feed best (and sometimes only) at the surface. Often such fishes are long and slender, able to dart at surface insects or at other surface fishes and in turn to dart away from predators; needlefishes, halfbeaks, and topminnows (such as killifish and mosquito fish) are good examples. Oceanic flying fishes escape their predators by gathering speed above the water surface, with the lower lobe of the tail providing thrust in the water. They then glide hundreds of yards on enlarged, winglike pectoral and pelvic fins. South American freshwater flying fishes escape their enemies by jumping and propelling their strongly keeled bodies out of the water.

 

So-called mid-water swimmers, the most common type of fish, are of many kinds and live in many habitats. The powerful fusiform tunas and the trouts, for example, are adapted for strong, fast swimming, the tunas to capture prey speedily in the open ocean and the trouts to cope with the swift currents of streams and rivers. The trout body form is well adapted to many habitats. Fishes that live in relatively quiet waters such as bays or lake shores or slow rivers usually are not strong, fast swimmers but are capable of short, quick bursts of speed to escape a predator. Many of these fishes have their sides flattened, examples being the sunfish and the freshwater angelfish of aquarists. Fish associated with the bottom or substrate usually are slow swimmers. Open-water plankton-feeding fishes almost always remain fusiform and are capable of rapid, strong movement (for example, sardines and herrings of the open ocean and also many small minnows of streams and lakes).

 

Bottom-living fishes are of many kinds and have undergone many types of modification of their body shape and swimming habits. Rays, which evolved from strong-swimming mid-water sharks, usually stay close to the bottom and move by undulating their large pectoral fins. Flounders live in a similar habitat and move over the bottom by undulating the entire body. Many bottom fishes dart from place to place, resting on the bottom between movements, a motion common in gobies. One goby relative, the mudskipper, has taken to living at the edge of pools along the shore of muddy mangrove swamps. It escapes its enemies by flipping rapidly over the mud, out of the water. Some catfishes, synbranchid eels, the so-called climbing perch, and a few other fishes venture out over damp ground to find more promising waters than those that they left. They move by wriggling their bodies, sometimes using strong pectoral fins; most have accessory air-breathing organs. Many bottom-dwelling fishes live in mud holes or rocky crevices. Marine eels and gobies commonly are found in such habitats and for the most part venture far beyond their cavelike homes. Some bottom dwellers, such as the clingfishes (Gobiesocidae), have developed powerful adhesive disks that enable them to remain in place on the substrate in areas such as rocky coasts, where the action of the waves is great.

 

The methods of reproduction in fishes are varied, but most fishes lay a large number of small eggs, fertilized and scattered outside of the body. The eggs of pelagic fishes usually remain suspended in the open water. Many shore and freshwater fishes lay eggs on the bottom or among plants. Some have adhesive eggs. The mortality of the young and especially of the eggs is very high, and often only a few individuals grow to maturity out of hundreds, thousands, and in some cases millions of eggs laid.

 

Males produce sperm, usually as a milky white substance called milt, in two (sometimes one) testes within the body cavity. In bony fishes a sperm duct leads from each testis to a urogenital opening behind the vent or anus. In sharks and rays and in cyclostomes the duct leads to a cloaca. Sometimes the pelvic fins are modified to help transmit the milt to the eggs at the female’s vent or on the substrate where the female has placed them. Sometimes accessory organs are used to fertilize females internally—for example, the claspers of many sharks and rays.

 

In the females the eggs are formed in two ovaries (sometimes only one) and pass through the ovaries to the urogenital opening and to the outside. In some fishes the eggs are fertilized internally but are shed before development takes place. Members of about a dozen families each of bony fishes (teleosts) and sharks bear live young. Many skates and rays also bear live young. In some bony fishes the eggs simply develop within the female, the young emerging when the eggs hatch (ovoviviparous). Others develop within the ovary and are nourished by ovarian tissues after hatching (viviparous). There are also other methods utilized by fishes to nourish young within the female. In all live-bearers the young are born at a relatively large size and are few in number. In one family of primarily marine fishes, the surfperches from the Pacific coast of North America, Japan, and Korea, the males of at least one species are born sexually mature, although they are not fully grown.

 

Some fishes are hermaphroditic—an individual producing both sperm and eggs, usually at different stages of its life. Self-fertilization, however, is probably rare.

 

Successful reproduction and, in many cases, defense of the eggs and the young are assured by rather stereotypical but often elaborate courtship and parental behaviour, either by the male or the female or both. Some fishes prepare nests by hollowing out depressions in the sand bottom (cichlids, for example), build nests with plant materials and sticky threads excreted by the kidneys (sticklebacks), or blow a cluster of mucus-covered bubbles at the water surface (gouramis). The eggs are laid in these structures. Some varieties of cichlids and catfishes incubate eggs in their mouths.

 

Some fishes, such as salmon, undergo long migrations from the ocean and up large rivers to spawn in the gravel beds where they themselves hatched (anadromous fishes). Some, such as the freshwater eels (family Anguillidae), live and grow to maturity in fresh water and migrate to the sea to spawn (catadromous fishes). Other fishes undertake shorter migrations from lakes into streams, within the ocean, or enter spawning habitats that they do not ordinarily occupy in other ways.

 

The basic structure and function of the fish body are similar to those of all other vertebrates. The usual four types of tissues are present: surface or epithelial, connective (bone, cartilage, and fibrous tissues, as well as their derivative, blood), nerve, and muscle tissues. In addition, the fish’s organs and organ systems parallel those of other vertebrates.

 

The typical fish body is streamlined and spindle-shaped, with an anterior head, a gill apparatus, and a heart, the latter lying in the midline just below the gill chamber. The body cavity, containing the vital organs, is situated behind the head in the lower anterior part of the body. The anus usually marks the posterior termination of the body cavity and most often occurs just in front of the base of the anal fin. The spinal cord and vertebral column continue from the posterior part of the head to the base of the tail fin, passing dorsal to the body cavity and through the caudal (tail) region behind the body cavity. Most of the body is of muscular tissue, a high proportion of which is necessitated by swimming. In the course of evolution this basic body plan has been modified repeatedly into the many varieties of fish shapes that exist today.

 

The skeleton forms an integral part of the fish’s locomotion system, as well as serving to protect vital parts. The internal skeleton consists of the skull bones (except for the roofing bones of the head, which are really part of the external skeleton), the vertebral column, and the fin supports (fin rays). The fin supports are derived from the external skeleton but will be treated here because of their close functional relationship to the internal skeleton. The internal skeleton of cyclostomes, sharks, and rays is of cartilage; that of many fossil groups and some primitive living fishes is mostly of cartilage but may include some bone. In place of the vertebral column, the earliest vertebrates had a fully developed notochord, a flexible stiff rod of viscous cells surrounded by a strong fibrous sheath. During the evolution of modern fishes the rod was replaced in part by cartilage and then by ossified cartilage. Sharks and rays retain a cartilaginous vertebral column; bony fishes have spool-shaped vertebrae that in the more primitive living forms only partially replace the notochord. The skull, including the gill arches and jaws of bony fishes, is fully, or at least partially, ossified. That of sharks and rays remains cartilaginous, at times partially replaced by calcium deposits but never by true bone.

 

The supportive elements of the fins (basal or radial bones or both) have changed greatly during fish evolution. Some of these changes are described in the section below (Evolution and paleontology). Most fishes possess a single dorsal fin on the midline of the back. Many have two and a few have three dorsal fins. The other fins are the single tail and anal fins and paired pelvic and pectoral fins. A small fin, the adipose fin, with hairlike fin rays, occurs in many of the relatively primitive teleosts (such as trout) on the back near the base of the caudal fin.

 

The skin of a fish must serve many functions. It aids in maintaining the osmotic balance, provides physical protection for the body, is the site of coloration, contains sensory receptors, and, in some fishes, functions in respiration. Mucous glands, which aid in maintaining the water balance and offer protection from bacteria, are extremely numerous in fish skin, especially in cyclostomes and teleosts. Since mucous glands are present in the modern lampreys, it is reasonable to assume that they were present in primitive fishes, such as the ancient Silurian and Devonian agnathans. Protection from abrasion and predation is another function of the fish skin, and dermal (skin) bone arose early in fish evolution in response to this need. It is thought that bone first evolved in skin and only later invaded the cartilaginous areas of the fish’s body, to provide additional support and protection. There is some argument as to which came first, cartilage or bone, and fossil evidence does not settle the question. In any event, dermal bone has played an important part in fish evolution and has different characteristics in different groups of fishes. Several groups are characterized at least in part by the kind of bony scales they possess.

 

Scales have played an important part in the evolution of fishes. Primitive fishes usually had thick bony plates or thick scales in several layers of bone, enamel, and related substances. Modern teleost fishes have scales of bone, which, while still protective, allow much more freedom of motion in the body. A few modern teleosts (some catfishes, sticklebacks, and others) have secondarily acquired bony plates in the skin. Modern and early sharks possessed placoid scales, a relatively primitive type of scale with a toothlike structure, consisting of an outside layer of enamel-like substance (vitrodentine), an inner layer of dentine, and a pulp cavity containing nerves and blood vessels. Primitive bony fishes had thick scales of either the ganoid or the cosmoid type. Cosmoid scales have a hard, enamel-like outer layer, an inner layer of cosmine (a form of dentine), and then a layer of vascular bone (isopedine). In ganoid scales the hard outer layer is different chemically and is called ganoin. Under this is a cosminelike layer and then a vascular bony layer. The thin, translucent bony scales of modern fishes, called cycloid and ctenoid (the latter distinguished by serrations at the edges), lack enameloid and dentine layers.

 

Skin has several other functions in fishes. It is well supplied with nerve endings and presumably receives tactile, thermal, and pain stimuli. Skin is also well supplied with blood vessels. Some fishes breathe in part through the skin, by the exchange of oxygen and carbon dioxide between the surrounding water and numerous small blood vessels near the skin surface.

 

Skin serves as protection through the control of coloration. Fishes exhibit an almost limitless range of colours. The colours often blend closely with the surroundings, effectively hiding the animal. Many fishes use bright colours for territorial advertisement or as recognition marks for other members of their own species, or sometimes for members of other species. Many fishes can change their colour to a greater or lesser degree, by movement of pigment within the pigment cells (chromatophores). Black pigment cells (melanophores), of almost universal occurrence in fishes, are often juxtaposed with other pigment cells. When placed beneath iridocytes or leucophores (bearing the silvery or white pigment guanine), melanophores produce structural colours of blue and green. These colours are often extremely intense, because they are formed by refraction of light through the needlelike crystals of guanine. The blue and green refracted colours are often relatively pure, lacking the red and yellow rays, which have been absorbed by the black pigment (melanin) of the melanophores. Yellow, orange, and red colours are produced by erythrophores, cells containing the appropriate carotenoid pigments. Other colours are produced by combinations of melanophores, erythrophores, and iridocytes.

 

The major portion of the body of most fishes consists of muscles. Most of the mass is trunk musculature, the fin muscles usually being relatively small. The caudal fin is usually the most powerful fin, being moved by the trunk musculature. The body musculature is usually arranged in rows of chevron-shaped segments on each side. Contractions of these segments, each attached to adjacent vertebrae and vertebral processes, bends the body on the vertebral joint, producing successive undulations of the body, passing from the head to the tail, and producing driving strokes of the tail. It is the latter that provides the strong forward movement for most fishes.

 

The digestive system, in a functional sense, starts at the mouth, with the teeth used to capture prey or collect plant foods. Mouth shape and tooth structure vary greatly in fishes, depending on the kind of food normally eaten. Most fishes are predacious, feeding on small invertebrates or other fishes and have simple conical teeth on the jaws, on at least some of the bones of the roof of the mouth, and on special gill arch structures just in front of the esophagus. The latter are throat teeth. Most predacious fishes swallow their prey whole, and the teeth are used for grasping and holding prey, for orienting prey to be swallowed (head first) and for working the prey toward the esophagus. There are a variety of tooth types in fishes. Some fishes, such as sharks and piranhas, have cutting teeth for biting chunks out of their victims. A shark’s tooth, although superficially like that of a piranha, appears in many respects to be a modified scale, while that of the piranha is like that of other bony fishes, consisting of dentine and enamel. Parrot fishes have beaklike mouths with short incisor-like teeth for breaking off coral and have heavy pavementlike throat teeth for crushing the coral. Some catfishes have small brushlike teeth, arranged in rows on the jaws, for scraping plant and animal growth from rocks. Many fishes (such as the Cyprinidae or minnows) have no jaw teeth at all but have very strong throat teeth.

 

Some fishes gather planktonic food by straining it from their gill cavities with numerous elongate stiff rods (gill rakers) anchored by one end to the gill bars. The food collected on these rods is passed to the throat, where it is swallowed. Most fishes have only short gill rakers that help keep food particles from escaping out the mouth cavity into the gill chamber.

 

Once reaching the throat, food enters a short, often greatly distensible esophagus, a simple tube with a muscular wall leading into a stomach. The stomach varies greatly in fishes, depending upon the diet. In most predacious fishes it is a simple straight or curved tube or pouch with a muscular wall and a glandular lining. Food is largely digested there and leaves the stomach in liquid form.

 

Between the stomach and the intestine, ducts enter the digestive tube from the liver and pancreas. The liver is a large, clearly defined organ. The pancreas may be embedded in it, diffused through it, or broken into small parts spread along some of the intestine. The junction between the stomach and the intestine is marked by a muscular valve. Pyloric ceca (blind sacs) occur in some fishes at this junction and have a digestive or absorptive function or both.

 

The intestine itself is quite variable in length, depending upon the fish’s diet. It is short in predacious forms, sometimes no longer than the body cavity, but long in herbivorous forms, being coiled and several times longer than the entire length of the fish in some species of South American catfishes. The intestine is primarily an organ for absorbing nutrients into the bloodstream. The larger its internal surface, the greater its absorptive efficiency, and a spiral valve is one method of increasing its absorption surface.

 

Sharks, rays, chimaeras, lungfishes, surviving chondrosteans, holosteans, and even a few of the more primitive teleosts have a spiral valve or at least traces of it in the intestine. Most modern teleosts have increased the area of the intestinal walls by having numerous folds and villi (fingerlike projections) somewhat like those in humans. Undigested substances are passed to the exterior through the anus in most teleost fishes. In lungfishes, sharks, and rays, it is first passed through the cloaca, a common cavity receiving the intestinal opening and the ducts from the urogenital system.

 

Oxygen and carbon dioxide dissolve in water, and most fishes exchange dissolved oxygen and carbon dioxide in water by means of the gills. The gills lie behind and to the side of the mouth cavity and consist of fleshy filaments supported by the gill arches and filled with blood vessels, which give gills a bright red colour. Water taken in continuously through the mouth passes backward between the gill bars and over the gill filaments, where the exchange of gases takes place. The gills are protected by a gill cover in teleosts and many other fishes but by flaps of skin in sharks, rays, and some of the older fossil fish groups. The blood capillaries in the gill filaments are close to the gill surface to take up oxygen from the water and to give up excess carbon dioxide to the water.

 

Most modern fishes have a hydrostatic (ballast) organ, called the swim bladder, that lies in the body cavity just below the kidney and above the stomach and intestine. It originated as a diverticulum of the digestive canal. In advanced teleosts, especially the acanthopterygians, the bladder has lost its connection with the digestive tract, a condition called physoclistic. The connection has been retained (physostomous) by many relatively primitive teleosts. In several unrelated lines of fishes, the bladder has become specialized as a lung or, at least, as a highly vascularized accessory breathing organ. Some fishes with such accessory organs are obligate air breathers and will drown if denied access to the surface, even in well-oxygenated water. Fishes with a hydrostatic form of swim bladder can control their depth by regulating the amount of gas in the bladder. The gas, mostly oxygen, is secreted into the bladder by special glands, rendering the fish more buoyant; the gas is absorbed into the bloodstream by another special organ, reducing the overall buoyancy and allowing the fish to sink. Some deep-sea fishes may have oils, rather than gas, in the bladder. Other deep-sea and some bottom-living forms have much-reduced swim bladders or have lost the organ entirely.

 

The swim bladder of fishes follows the same developmental pattern as the lungs of land vertebrates. There is no doubt that the two structures have the same historical origin in primitive fishes. More or less intermediate forms still survive among the more primitive types of fishes, such as the lungfishes Lepidosiren and Protopterus.

 

The circulatory, or blood vascular, system consists of the heart, the arteries, the capillaries, and the veins. It is in the capillaries that the interchange of oxygen, carbon dioxide, nutrients, and other substances such as hormones and waste products takes place. The capillaries lead to the veins, which return the venous blood with its waste products to the heart, kidneys, and gills. There are two kinds of capillary beds: those in the gills and those in the rest of the body. The heart, a folded continuous muscular tube with three or four saclike enlargements, undergoes rhythmic contractions and receives venous blood in a sinus venosus. It passes the blood to an auricle and then into a thick muscular pump, the ventricle. From the ventricle the blood goes to a bulbous structure at the base of a ventral aorta just below the gills. The blood passes to the afferent (receiving) arteries of the gill arches and then to the gill capillaries. There waste gases are given off to the environment, and oxygen is absorbed. The oxygenated blood enters efferent (exuant) arteries of the gill arches and then flows into the dorsal aorta. From there blood is distributed to the tissues and organs of the body. One-way valves prevent backflow. The circulation of fishes thus differs from that of the reptiles, birds, and mammals in that oxygenated blood is not returned to the heart prior to distribution to the other parts of the body.

 

The primary excretory organ in fishes, as in other vertebrates, is the kidney. In fishes some excretion also takes place in the digestive tract, skin, and especially the gills (where ammonia is given off). Compared with land vertebrates, fishes have a special problem in maintaining their internal environment at a constant concentration of water and dissolved substances, such as salts. Proper balance of the internal environment (homeostasis) of a fish is in a great part maintained by the excretory system, especially the kidney.

 

The kidney, gills, and skin play an important role in maintaining a fish’s internal environment and checking the effects of osmosis. Marine fishes live in an environment in which the water around them has a greater concentration of salts than they can have inside their body and still maintain life. Freshwater fishes, on the other hand, live in water with a much lower concentration of salts than they require inside their bodies. Osmosis tends to promote the loss of water from the body of a marine fish and absorption of water by that of a freshwater fish. Mucus in the skin tends to slow the process but is not a sufficient barrier to prevent the movement of fluids through the permeable skin. When solutions on two sides of a permeable membrane have different concentrations of dissolved substances, water will pass through the membrane into the more concentrated solution, while the dissolved chemicals move into the area of lower concentration (diffusion).

 

The kidney of freshwater fishes is often larger in relation to body weight than that of marine fishes. In both groups the kidney excretes wastes from the body, but the kidney of freshwater fishes also excretes large amounts of water, counteracting the water absorbed through the skin. Freshwater fishes tend to lose salt to the environment and must replace it. They get some salt from their food, but the gills and skin inside the mouth actively absorb salt from water passed through the mouth. This absorption is performed by special cells capable of moving salts against the diffusion gradient. Freshwater fishes drink very little water and take in little water with their food.

 

Marine fishes must conserve water, and therefore their kidneys excrete little water. To maintain their water balance, marine fishes drink large quantities of seawater, retaining most of the water and excreting the salt. Most nitrogenous waste in marine fishes appears to be secreted by the gills as ammonia. Marine fishes can excrete salt by clusters of special cells (chloride cells) in the gills.

 

There are several teleosts—for example, the salmon—that travel between fresh water and seawater and must adjust to the reversal of osmotic gradients. They adjust their physiological processes by spending time (often surprisingly little time) in the intermediate brackish environment.

 

Marine hagfishes, sharks, and rays have osmotic concentrations in their blood about equal to that of seawater and so do not have to drink water nor perform much physiological work to maintain their osmotic balance. In sharks and rays the osmotic concentration is kept high by retention of urea in the blood. Freshwater sharks have a lowered concentration of urea in the blood.

 

Endocrine glands secrete their products into the bloodstream and body tissues and, along with the central nervous system, control and regulate many kinds of body functions. Cyclostomes have a well-developed endocrine system, and presumably it was well developed in the early Agnatha, ancestral to modern fishes. Although the endocrine system in fishes is similar to that of higher vertebrates, there are numerous differences in detail. The pituitary, the thyroid, the suprarenals, the adrenals, the pancreatic islets, the sex glands (ovaries and testes), the inner wall of the intestine, and the bodies of the ultimobranchial gland make up the endocrine system in fishes. There are some others whose function is not well understood. These organs regulate sexual activity and reproduction, growth, osmotic pressure, general metabolic activities such as the storage of fat and the utilization of foodstuffs, blood pressure, and certain aspects of skin colour. Many of these activities are also controlled in part by the central nervous system, which works with the endocrine system in maintaining the life of a fish. Some parts of the endocrine system are developmentally, and undoubtedly evolutionarily, derived from the nervous system.

 

As in all vertebrates, the nervous system of fishes is the primary mechanism coordinating body activities, as well as integrating these activities in the appropriate manner with stimuli from the environment. The central nervous system, consisting of the brain and spinal cord, is the primary integrating mechanism. The peripheral nervous system, consisting of nerves that connect the brain and spinal cord to various body organs, carries sensory information from special receptor organs such as the eyes, internal ears, nares (sense of smell), taste glands, and others to the integrating centres of the brain and spinal cord. The peripheral nervous system also carries information via different nerve cells from the integrating centres of the brain and spinal cord. This coded information is carried to the various organs and body systems, such as the skeletal muscular system, for appropriate action in response to the original external or internal stimulus. Another branch of the nervous system, the autonomic nervous system, helps to coordinate the activities of many glands and organs and is itself closely connected to the integrating centres of the brain.

 

The brain of the fish is divided into several anatomical and functional parts, all closely interconnected but each serving as the primary centre of integrating particular kinds of responses and activities. Several of these centres or parts are primarily associated with one type of sensory perception, such as sight, hearing, or smell (olfaction).

 

The sense of smell is important in almost all fishes. Certain eels with tiny eyes depend mostly on smell for location of food. The olfactory, or nasal, organ of fishes is located on the dorsal surface of the snout. The lining of the nasal organ has special sensory cells that perceive chemicals dissolved in the water, such as substances from food material, and send sensory information to the brain by way of the first cranial nerve. Odour also serves as an alarm system. Many fishes, especially various species of freshwater minnows, react with alarm to a chemical released from the skin of an injured member of their own species.

 

Many fishes have a well-developed sense of taste, and tiny pitlike taste buds or organs are located not only within their mouth cavities but also over their heads and parts of their body. Catfishes, which often have poor vision, have barbels (“whiskers”) that serve as supplementary taste organs, those around the mouth being actively used to search out food on the bottom. Some species of naturally blind cave fishes are especially well supplied with taste buds, which often cover most of their body surface.

 

Sight is extremely important in most fishes. The eye of a fish is basically like that of all other vertebrates, but the eyes of fishes are extremely varied in structure and adaptation. In general, fishes living in dark and dim water habitats have large eyes, unless they have specialized in some compensatory way so that another sense (such as smell) is dominant, in which case the eyes will often be reduced. Fishes living in brightly lighted shallow waters often will have relatively small but efficient eyes. Cyclostomes have somewhat less elaborate eyes than other fishes, with skin stretched over the eyeball perhaps making their vision somewhat less effective. Most fishes have a spherical lens and accommodate their vision to far or near subjects by moving the lens within the eyeball. A few sharks accommodate by changing the shape of the lens, as in land vertebrates. Those fishes that are heavily dependent upon the eyes have especially strong muscles for accommodation. Most fishes see well, despite the restrictions imposed by frequent turbidity of the water and by light refraction.

 

Fossil evidence suggests that colour vision evolved in fishes more than 300 million years ago, but not all living fishes have retained this ability. Experimental evidence indicates that many shallow-water fishes, if not all, have colour vision and see some colours especially well, but some bottom-dwelling shore fishes live in areas where the water is sufficiently deep to filter out most if not all colours, and these fishes apparently never see colours. When tested in shallow water, they apparently are unable to respond to colour differences.

 

Sound perception and balance are intimately associated senses in a fish. The organs of hearing are entirely internal, located within the skull, on each side of the brain and somewhat behind the eyes. Sound waves, especially those of low frequencies, travel readily through water and impinge directly upon the bones and fluids of the head and body, to be transmitted to the hearing organs. Fishes readily respond to sound; for example, a trout conditioned to escape by the approach of fishermen will take flight upon perceiving footsteps on a stream bank even if it cannot see a fisherman. Compared with humans, however, the range of sound frequencies heard by fishes is greatly restricted. Many fishes communicate with each other by producing sounds in their swim bladders, in their throats by rasping their teeth, and in other ways.

 

A fish or other vertebrate seldom has to rely on a single type of sensory information to determine the nature of the environment around it. A catfish uses taste and touch when examining a food object with its oral barbels. Like most other animals, fishes have many touch receptors over their body surface. Pain and temperature receptors also are present in fishes and presumably produce the same kind of information to a fish as to humans. Fishes react in a negative fashion to stimuli that would be painful to human beings, suggesting that they feel a sensation of pain.

 

An important sensory system in fishes that is absent in other vertebrates (except some amphibians) is the lateral line system. This consists of a series of heavily innervated small canals located in the skin and bone around the eyes, along the lower jaw, over the head, and down the mid-side of the body, where it is associated with the scales. Intermittently along these canals are located tiny sensory organs (pit organs) that apparently detect changes in pressure. The system allows a fish to sense changes in water currents and pressure, thereby helping the fish to orient itself to the various changes that occur in the physical environment.

  

"Man-appetite craves fresh baked goods." It speaks like a caveman and reads like a headline. 80 years later the endocrine disruptors had reduced the man-appetite to mere baked goods and chips.

Anahata

 

Element: Air

 

This is my chakra project, It was a journey which taught me about myself and others. The simple images represent first a merge between the conscious and the subconscious and explores the physical connection of that hyperconscious with the human body (through the endocrine system and nervous system) and our physical surroundings. Each chakra corresponds to an element and a glad within the endocrine system/a part of the body where the energy of that chakra resides in a swirl of energy.

 

Part 2 of a global assessment

 

This report provides an update and further assessment of the sources, fate and effects of microplastics in the marine environment, carried out by Working Group 40 (WG40) of GESAMP (The Joint Group of Experts on Scientific Aspects of Marine Protection). It follows publication of the first assessment report in this series in April 2015 (GESAMP 2015). The issue of marine plastic litter was raised during the inaugural meeting of the United Nations Environment Assembly (UNEA) in June 2014. Delegates from 160 countries adopted Resolution 1/6 on ‘Marine plastic debris and microplastics’ (Annex I). The resolution welcomed the work being undertaken by GESAMP on microplastics and requested the Executive Director of UNEP to carry out a study on marine plastics and microplastics. This was to be based on a combination of existing and new studies, including WG40. This provided the motivation for GESAMP to revise the original terms of reference to reflect both the request from UNEP to contribute to the UNEA study, and the key recommendations from the WG40 2015 report.

 

Each main section begins with key messages followed by a short summary of related findings from the first report. Each section ends with conclusions, knowledge gaps and research priorities. Greater effort has been made to describe the nature, distribution and magnitude of sources of macro- and microplastics. These are described by sea-based and land-based sectors, together with the main entry points to the ocean. Spatial (regional) and temporal differences in both sources and entry points are examined. One previously unrecognized source of secondary microplastics highlighted is debris from vehicle tyres.

 

The distribution of microplastics in the five main ocean compartments (sea surface, water column, shoreline, seabed and biota) are described, together with the transport mechanisms that regulate fluxes between compartments. Regional ‘hot-spots’ of sources, distribution and accumulation zones are reported, in response to the UNEA request.

 

The effects of microplastics on marine biota have been explored in greater detail.

 

Greater attention has been given to the interaction of microplastics with biota. A comprehensive literature review has been assembled with tables summarising the occurrence of microplastics in a wide variety of marine organisms and seabirds. There does appear to be an association between uptake of microplastics and changes in the physiological or biochemical response in some species, observed in laboratory experiments. It is not clear whether this will be significant at a population level with current observed microplastic numbers. The current understanding of the interaction of plasticassociated chemicals with biota is reviewed, using laboratory-based experiments, theoretical studies and field-based observations. It appears very likely that this interaction will be dependent on:

 

the species;

the relative degree of contamination of the plastic, the biota concerned and the marine environment (sediment, water, foodstuff) in that region;

the size, shape and type of plastics;

and several time-related variables (e.g. environmental transport, gut desorption rates).

 

This remains a contentious area of research. The occurrence of nano-sized plastics in the marine environment has yet to be established and we are dependent on drawing inferences from other fields of science and medicine when considering possible effects. Microplastics can act as vectors for both indigenous and non-indigenous species. Examples include pathogenic Vibrio bacteria, eggs of marine insects and the resting stages of several jellyfish species.

 

A new section considers the possible effect of microplastics on commercial fish and shellfish. Microplastics have been found in a variety of commercial fish and shellfish, including samples purchased from retail outlets. Generally the numbers of particles per organism are very small, even for filter-feeding bivalves in coastal areas bordered by high coastal populations. At these levels it is not considered likely that microplastics will influence the breeding/development success of fish stocks (food security) nor represent an objective risk to human health (food safety). However, data are rather scarce and this is an area that justifies further attention.

 

The economic aspects of microplastic contamination are considered in another new section. This relies heavily on studies looking at the effects of macrodebris on various sectors (e.g. fisheries, shipping, tourism, waste management), given the paucity of knowledge of direct economic effects of microplastics. Acting on macroplastics may be easier to justify, as the social, ecological and economic effects are easier to demonstrate. This in turn will reduce the quantities of secondary microplastics being generated in the ocean. One significant cost that may be incurred would be the provision of wastewater treatment capable of filtering out microplastics. Such systems are relatively common in some rich countries but absent in many developing nations. Clearly, there are many other reasons to introduce improved wastewater treatment (nutrient reduction, disease prevention), with reduction in microplastics being an additional benefit.

 

Social aspects are focused around factors influencing long-term behaviour change, including risk perceptions, perceived responsibility and the influence of demographics. This is key to implementing effective, acceptable measures.

 

A separate section summarizes good practice guidance on sampling and analysis at sea, in sediments and in biological samples. There are no global ‘standards’ but if these guidelines are followed then it will be easier to generate quality-assured data, in a cost-effective manner, and for datasets to be compared and combined with more confidence.

 

The final main section presents an initial risk assessment framework. Having described some basic principles about risk, likelihood and consequences the section provides a conceptual framework and two case examples (one real, one hypothetical) of how the framework can be utilized.

 

The report concludes with key conclusions and recommendations for further research.

Fish, any of approximately 34,000 species of vertebrate animals (phylum Chordata) found in the fresh and salt waters of the world. Living species range from the primitive jawless lampreys and hagfishes through the cartilaginous sharks, skates, and rays to the abundant and diverse bony fishes. Most fish species are cold-blooded; however, one species, the opah (Lampris guttatus), is warm-blooded.

 

The term fish is applied to a variety of vertebrates of several evolutionary lines. It describes a life-form rather than a taxonomic group. As members of the phylum Chordata, fish share certain features with other vertebrates. These features are gill slits at some point in the life cycle, a notochord, or skeletal supporting rod, a dorsal hollow nerve cord, and a tail. Living fishes represent some five classes, which are as distinct from one another as are the four classes of familiar air-breathing animals—amphibians, reptiles, birds, and mammals. For example, the jawless fishes (Agnatha) have gills in pouches and lack limb girdles. Extant agnathans are the lampreys and the hagfishes. As the name implies, the skeletons of fishes of the class Chondrichthyes (from chondr, “cartilage,” and ichthyes, “fish”) are made entirely of cartilage. Modern fish of this class lack a swim bladder, and their scales and teeth are made up of the same placoid material. Sharks, skates, and rays are examples of cartilaginous fishes. The bony fishes are by far the largest class. Examples range from the tiny seahorse to the 450-kg (1,000-pound) blue marlin, from the flattened soles and flounders to the boxy puffers and ocean sunfishes. Unlike the scales of the cartilaginous fishes, those of bony fishes, when present, grow throughout life and are made up of thin overlapping plates of bone. Bony fishes also have an operculum that covers the gill slits.

 

The study of fishes, the science of ichthyology, is of broad importance. Fishes are of interest to humans for many reasons, the most important being their relationship with and dependence on the environment. A more obvious reason for interest in fishes is their role as a moderate but important part of the world’s food supply. This resource, once thought unlimited, is now realized to be finite and in delicate balance with the biological, chemical, and physical factors of the aquatic environment. Overfishing, pollution, and alteration of the environment are the chief enemies of proper fisheries management, both in fresh waters and in the ocean. (For a detailed discussion of the technology and economics of fisheries, see commercial fishing.) Another practical reason for studying fishes is their use in disease control. As predators on mosquito larvae, they help curb malaria and other mosquito-borne diseases.

 

Fishes are valuable laboratory animals in many aspects of medical and biological research. For example, the readiness of many fishes to acclimate to captivity has allowed biologists to study behaviour, physiology, and even ecology under relatively natural conditions. Fishes have been especially important in the study of animal behaviour, where research on fishes has provided a broad base for the understanding of the more flexible behaviour of the higher vertebrates. The zebra fish is used as a model in studies of gene expression.

 

There are aesthetic and recreational reasons for an interest in fishes. Millions of people keep live fishes in home aquariums for the simple pleasure of observing the beauty and behaviour of animals otherwise unfamiliar to them. Aquarium fishes provide a personal challenge to many aquarists, allowing them to test their ability to keep a small section of the natural environment in their homes. Sportfishing is another way of enjoying the natural environment, also indulged in by millions of people every year. Interest in aquarium fishes and sportfishing supports multimillion-dollar industries throughout the world.

 

Fishes have been in existence for more than 450 million years, during which time they have evolved repeatedly to fit into almost every conceivable type of aquatic habitat. In a sense, land vertebrates are simply highly modified fishes: when fishes colonized the land habitat, they became tetrapod (four-legged) land vertebrates. The popular conception of a fish as a slippery, streamlined aquatic animal that possesses fins and breathes by gills applies to many fishes, but far more fishes deviate from that conception than conform to it. For example, the body is elongate in many forms and greatly shortened in others; the body is flattened in some (principally in bottom-dwelling fishes) and laterally compressed in many others; the fins may be elaborately extended, forming intricate shapes, or they may be reduced or even lost; and the positions of the mouth, eyes, nostrils, and gill openings vary widely. Air breathers have appeared in several evolutionary lines.

 

Many fishes are cryptically coloured and shaped, closely matching their respective environments; others are among the most brilliantly coloured of all organisms, with a wide range of hues, often of striking intensity, on a single individual. The brilliance of pigments may be enhanced by the surface structure of the fish, so that it almost seems to glow. A number of unrelated fishes have actual light-producing organs. Many fishes are able to alter their coloration—some for the purpose of camouflage, others for the enhancement of behavioral signals.

 

Fishes range in adult length from less than 10 mm (0.4 inch) to more than 20 metres (60 feet) and in weight from about 1.5 grams (less than 0.06 ounce) to many thousands of kilograms. Some live in shallow thermal springs at temperatures slightly above 42 °C (100 °F), others in cold Arctic seas a few degrees below 0 °C (32 °F) or in cold deep waters more than 4,000 metres (13,100 feet) beneath the ocean surface. The structural and, especially, the physiological adaptations for life at such extremes are relatively poorly known and provide the scientifically curious with great incentive for study.

 

Almost all natural bodies of water bear fish life, the exceptions being very hot thermal ponds and extremely salt-alkaline lakes, such as the Dead Sea in Asia and the Great Salt Lake in North America. The present distribution of fishes is a result of the geological history and development of Earth as well as the ability of fishes to undergo evolutionary change and to adapt to the available habitats. Fishes may be seen to be distributed according to habitat and according to geographical area. Major habitat differences are marine and freshwater. For the most part, the fishes in a marine habitat differ from those in a freshwater habitat, even in adjacent areas, but some, such as the salmon, migrate from one to the other. The freshwater habitats may be seen to be of many kinds. Fishes found in mountain torrents, Arctic lakes, tropical lakes, temperate streams, and tropical rivers will all differ from each other, both in obvious gross structure and in physiological attributes. Even in closely adjacent habitats where, for example, a tropical mountain torrent enters a lowland stream, the fish fauna will differ. The marine habitats can be divided into deep ocean floors (benthic), mid-water oceanic (bathypelagic), surface oceanic (pelagic), rocky coast, sandy coast, muddy shores, bays, estuaries, and others. Also, for example, rocky coastal shores in tropical and temperate regions will have different fish faunas, even when such habitats occur along the same coastline.

 

Although much is known about the present geographical distribution of fishes, far less is known about how that distribution came about. Many parts of the fish fauna of the fresh waters of North America and Eurasia are related and undoubtedly have a common origin. The faunas of Africa and South America are related, extremely old, and probably an expression of the drifting apart of the two continents. The fauna of southern Asia is related to that of Central Asia, and some of it appears to have entered Africa. The extremely large shore-fish faunas of the Indian and tropical Pacific oceans comprise a related complex, but the tropical shore fauna of the Atlantic, although containing Indo-Pacific components, is relatively limited and probably younger. The Arctic and Antarctic marine faunas are quite different from each other. The shore fauna of the North Pacific is quite distinct, and that of the North Atlantic more limited and probably younger. Pelagic oceanic fishes, especially those in deep waters, are similar the world over, showing little geographical isolation in terms of family groups. The deep oceanic habitat is very much the same throughout the world, but species differences do exist, showing geographical areas determined by oceanic currents and water masses.

 

All aspects of the life of a fish are closely correlated with adaptation to the total environment, physical, chemical, and biological. In studies, all the interdependent aspects of fish, such as behaviour, locomotion, reproduction, and physical and physiological characteristics, must be taken into account.

 

Correlated with their adaptation to an extremely wide variety of habitats is the extremely wide variety of life cycles that fishes display. The great majority hatch from relatively small eggs a few days to several weeks or more after the eggs are scattered in the water. Newly hatched young are still partially undeveloped and are called larvae until body structures such as fins, skeleton, and some organs are fully formed. Larval life is often very short, usually less than a few weeks, but it can be very long, some lampreys continuing as larvae for at least five years. Young and larval fishes, before reaching sexual maturity, must grow considerably, and their small size and other factors often dictate that they live in a habitat different than that of the adults. For example, most tropical marine shore fishes have pelagic larvae. Larval food also is different, and larval fishes often live in shallow waters, where they may be less exposed to predators.

 

After a fish reaches adult size, the length of its life is subject to many factors, such as innate rates of aging, predation pressure, and the nature of the local climate. The longevity of a species in the protected environment of an aquarium may have nothing to do with how long members of that species live in the wild. Many small fishes live only one to three years at the most. In some species, however, individuals may live as long as 10 or 20 or even 100 years.

 

Fish behaviour is a complicated and varied subject. As in almost all animals with a central nervous system, the nature of a response of an individual fish to stimuli from its environment depends upon the inherited characteristics of its nervous system, on what it has learned from past experience, and on the nature of the stimuli. Compared with the variety of human responses, however, that of a fish is stereotyped, not subject to much modification by “thought” or learning, and investigators must guard against anthropomorphic interpretations of fish behaviour.

 

Fishes perceive the world around them by the usual senses of sight, smell, hearing, touch, and taste and by special lateral line water-current detectors. In the few fishes that generate electric fields, a process that might best be called electrolocation aids in perception. One or another of these senses often is emphasized at the expense of others, depending upon the fish’s other adaptations. In fishes with large eyes, the sense of smell may be reduced; others, with small eyes, hunt and feed primarily by smell (such as some eels).

 

Specialized behaviour is primarily concerned with the three most important activities in the fish’s life: feeding, reproduction, and escape from enemies. Schooling behaviour of sardines on the high seas, for instance, is largely a protective device to avoid enemies, but it is also associated with and modified by their breeding and feeding requirements. Predatory fishes are often solitary, lying in wait to dart suddenly after their prey, a kind of locomotion impossible for beaked parrot fishes, which feed on coral, swimming in small groups from one coral head to the next. In addition, some predatory fishes that inhabit pelagic environments, such as tunas, often school.

 

Sleep in fishes, all of which lack true eyelids, consists of a seemingly listless state in which the fish maintains its balance but moves slowly. If attacked or disturbed, most can dart away. A few kinds of fishes lie on the bottom to sleep. Most catfishes, some loaches, and some eels and electric fishes are strictly nocturnal, being active and hunting for food during the night and retiring during the day to holes, thick vegetation, or other protective parts of the environment.

 

Communication between members of a species or between members of two or more species often is extremely important, especially in breeding behaviour (see below Reproduction). The mode of communication may be visual, as between the small so-called cleaner fish and a large fish of a very different species. The larger fish often allows the cleaner to enter its mouth to remove gill parasites. The cleaner is recognized by its distinctive colour and actions and therefore is not eaten, even if the larger fish is normally a predator. Communication is often chemical, signals being sent by specific chemicals called pheromones.

 

Many fishes have a streamlined body and swim freely in open water. Fish locomotion is closely correlated with habitat and ecological niche (the general position of the animal to its environment).

 

Many fishes in both marine and fresh waters swim at the surface and have mouths adapted to feed best (and sometimes only) at the surface. Often such fishes are long and slender, able to dart at surface insects or at other surface fishes and in turn to dart away from predators; needlefishes, halfbeaks, and topminnows (such as killifish and mosquito fish) are good examples. Oceanic flying fishes escape their predators by gathering speed above the water surface, with the lower lobe of the tail providing thrust in the water. They then glide hundreds of yards on enlarged, winglike pectoral and pelvic fins. South American freshwater flying fishes escape their enemies by jumping and propelling their strongly keeled bodies out of the water.

 

So-called mid-water swimmers, the most common type of fish, are of many kinds and live in many habitats. The powerful fusiform tunas and the trouts, for example, are adapted for strong, fast swimming, the tunas to capture prey speedily in the open ocean and the trouts to cope with the swift currents of streams and rivers. The trout body form is well adapted to many habitats. Fishes that live in relatively quiet waters such as bays or lake shores or slow rivers usually are not strong, fast swimmers but are capable of short, quick bursts of speed to escape a predator. Many of these fishes have their sides flattened, examples being the sunfish and the freshwater angelfish of aquarists. Fish associated with the bottom or substrate usually are slow swimmers. Open-water plankton-feeding fishes almost always remain fusiform and are capable of rapid, strong movement (for example, sardines and herrings of the open ocean and also many small minnows of streams and lakes).

 

Bottom-living fishes are of many kinds and have undergone many types of modification of their body shape and swimming habits. Rays, which evolved from strong-swimming mid-water sharks, usually stay close to the bottom and move by undulating their large pectoral fins. Flounders live in a similar habitat and move over the bottom by undulating the entire body. Many bottom fishes dart from place to place, resting on the bottom between movements, a motion common in gobies. One goby relative, the mudskipper, has taken to living at the edge of pools along the shore of muddy mangrove swamps. It escapes its enemies by flipping rapidly over the mud, out of the water. Some catfishes, synbranchid eels, the so-called climbing perch, and a few other fishes venture out over damp ground to find more promising waters than those that they left. They move by wriggling their bodies, sometimes using strong pectoral fins; most have accessory air-breathing organs. Many bottom-dwelling fishes live in mud holes or rocky crevices. Marine eels and gobies commonly are found in such habitats and for the most part venture far beyond their cavelike homes. Some bottom dwellers, such as the clingfishes (Gobiesocidae), have developed powerful adhesive disks that enable them to remain in place on the substrate in areas such as rocky coasts, where the action of the waves is great.

 

The methods of reproduction in fishes are varied, but most fishes lay a large number of small eggs, fertilized and scattered outside of the body. The eggs of pelagic fishes usually remain suspended in the open water. Many shore and freshwater fishes lay eggs on the bottom or among plants. Some have adhesive eggs. The mortality of the young and especially of the eggs is very high, and often only a few individuals grow to maturity out of hundreds, thousands, and in some cases millions of eggs laid.

 

Males produce sperm, usually as a milky white substance called milt, in two (sometimes one) testes within the body cavity. In bony fishes a sperm duct leads from each testis to a urogenital opening behind the vent or anus. In sharks and rays and in cyclostomes the duct leads to a cloaca. Sometimes the pelvic fins are modified to help transmit the milt to the eggs at the female’s vent or on the substrate where the female has placed them. Sometimes accessory organs are used to fertilize females internally—for example, the claspers of many sharks and rays.

 

In the females the eggs are formed in two ovaries (sometimes only one) and pass through the ovaries to the urogenital opening and to the outside. In some fishes the eggs are fertilized internally but are shed before development takes place. Members of about a dozen families each of bony fishes (teleosts) and sharks bear live young. Many skates and rays also bear live young. In some bony fishes the eggs simply develop within the female, the young emerging when the eggs hatch (ovoviviparous). Others develop within the ovary and are nourished by ovarian tissues after hatching (viviparous). There are also other methods utilized by fishes to nourish young within the female. In all live-bearers the young are born at a relatively large size and are few in number. In one family of primarily marine fishes, the surfperches from the Pacific coast of North America, Japan, and Korea, the males of at least one species are born sexually mature, although they are not fully grown.

 

Some fishes are hermaphroditic—an individual producing both sperm and eggs, usually at different stages of its life. Self-fertilization, however, is probably rare.

 

Successful reproduction and, in many cases, defense of the eggs and the young are assured by rather stereotypical but often elaborate courtship and parental behaviour, either by the male or the female or both. Some fishes prepare nests by hollowing out depressions in the sand bottom (cichlids, for example), build nests with plant materials and sticky threads excreted by the kidneys (sticklebacks), or blow a cluster of mucus-covered bubbles at the water surface (gouramis). The eggs are laid in these structures. Some varieties of cichlids and catfishes incubate eggs in their mouths.

 

Some fishes, such as salmon, undergo long migrations from the ocean and up large rivers to spawn in the gravel beds where they themselves hatched (anadromous fishes). Some, such as the freshwater eels (family Anguillidae), live and grow to maturity in fresh water and migrate to the sea to spawn (catadromous fishes). Other fishes undertake shorter migrations from lakes into streams, within the ocean, or enter spawning habitats that they do not ordinarily occupy in other ways.

 

The basic structure and function of the fish body are similar to those of all other vertebrates. The usual four types of tissues are present: surface or epithelial, connective (bone, cartilage, and fibrous tissues, as well as their derivative, blood), nerve, and muscle tissues. In addition, the fish’s organs and organ systems parallel those of other vertebrates.

 

The typical fish body is streamlined and spindle-shaped, with an anterior head, a gill apparatus, and a heart, the latter lying in the midline just below the gill chamber. The body cavity, containing the vital organs, is situated behind the head in the lower anterior part of the body. The anus usually marks the posterior termination of the body cavity and most often occurs just in front of the base of the anal fin. The spinal cord and vertebral column continue from the posterior part of the head to the base of the tail fin, passing dorsal to the body cavity and through the caudal (tail) region behind the body cavity. Most of the body is of muscular tissue, a high proportion of which is necessitated by swimming. In the course of evolution this basic body plan has been modified repeatedly into the many varieties of fish shapes that exist today.

 

The skeleton forms an integral part of the fish’s locomotion system, as well as serving to protect vital parts. The internal skeleton consists of the skull bones (except for the roofing bones of the head, which are really part of the external skeleton), the vertebral column, and the fin supports (fin rays). The fin supports are derived from the external skeleton but will be treated here because of their close functional relationship to the internal skeleton. The internal skeleton of cyclostomes, sharks, and rays is of cartilage; that of many fossil groups and some primitive living fishes is mostly of cartilage but may include some bone. In place of the vertebral column, the earliest vertebrates had a fully developed notochord, a flexible stiff rod of viscous cells surrounded by a strong fibrous sheath. During the evolution of modern fishes the rod was replaced in part by cartilage and then by ossified cartilage. Sharks and rays retain a cartilaginous vertebral column; bony fishes have spool-shaped vertebrae that in the more primitive living forms only partially replace the notochord. The skull, including the gill arches and jaws of bony fishes, is fully, or at least partially, ossified. That of sharks and rays remains cartilaginous, at times partially replaced by calcium deposits but never by true bone.

 

The supportive elements of the fins (basal or radial bones or both) have changed greatly during fish evolution. Some of these changes are described in the section below (Evolution and paleontology). Most fishes possess a single dorsal fin on the midline of the back. Many have two and a few have three dorsal fins. The other fins are the single tail and anal fins and paired pelvic and pectoral fins. A small fin, the adipose fin, with hairlike fin rays, occurs in many of the relatively primitive teleosts (such as trout) on the back near the base of the caudal fin.

 

The skin of a fish must serve many functions. It aids in maintaining the osmotic balance, provides physical protection for the body, is the site of coloration, contains sensory receptors, and, in some fishes, functions in respiration. Mucous glands, which aid in maintaining the water balance and offer protection from bacteria, are extremely numerous in fish skin, especially in cyclostomes and teleosts. Since mucous glands are present in the modern lampreys, it is reasonable to assume that they were present in primitive fishes, such as the ancient Silurian and Devonian agnathans. Protection from abrasion and predation is another function of the fish skin, and dermal (skin) bone arose early in fish evolution in response to this need. It is thought that bone first evolved in skin and only later invaded the cartilaginous areas of the fish’s body, to provide additional support and protection. There is some argument as to which came first, cartilage or bone, and fossil evidence does not settle the question. In any event, dermal bone has played an important part in fish evolution and has different characteristics in different groups of fishes. Several groups are characterized at least in part by the kind of bony scales they possess.

 

Scales have played an important part in the evolution of fishes. Primitive fishes usually had thick bony plates or thick scales in several layers of bone, enamel, and related substances. Modern teleost fishes have scales of bone, which, while still protective, allow much more freedom of motion in the body. A few modern teleosts (some catfishes, sticklebacks, and others) have secondarily acquired bony plates in the skin. Modern and early sharks possessed placoid scales, a relatively primitive type of scale with a toothlike structure, consisting of an outside layer of enamel-like substance (vitrodentine), an inner layer of dentine, and a pulp cavity containing nerves and blood vessels. Primitive bony fishes had thick scales of either the ganoid or the cosmoid type. Cosmoid scales have a hard, enamel-like outer layer, an inner layer of cosmine (a form of dentine), and then a layer of vascular bone (isopedine). In ganoid scales the hard outer layer is different chemically and is called ganoin. Under this is a cosminelike layer and then a vascular bony layer. The thin, translucent bony scales of modern fishes, called cycloid and ctenoid (the latter distinguished by serrations at the edges), lack enameloid and dentine layers.

 

Skin has several other functions in fishes. It is well supplied with nerve endings and presumably receives tactile, thermal, and pain stimuli. Skin is also well supplied with blood vessels. Some fishes breathe in part through the skin, by the exchange of oxygen and carbon dioxide between the surrounding water and numerous small blood vessels near the skin surface.

 

Skin serves as protection through the control of coloration. Fishes exhibit an almost limitless range of colours. The colours often blend closely with the surroundings, effectively hiding the animal. Many fishes use bright colours for territorial advertisement or as recognition marks for other members of their own species, or sometimes for members of other species. Many fishes can change their colour to a greater or lesser degree, by movement of pigment within the pigment cells (chromatophores). Black pigment cells (melanophores), of almost universal occurrence in fishes, are often juxtaposed with other pigment cells. When placed beneath iridocytes or leucophores (bearing the silvery or white pigment guanine), melanophores produce structural colours of blue and green. These colours are often extremely intense, because they are formed by refraction of light through the needlelike crystals of guanine. The blue and green refracted colours are often relatively pure, lacking the red and yellow rays, which have been absorbed by the black pigment (melanin) of the melanophores. Yellow, orange, and red colours are produced by erythrophores, cells containing the appropriate carotenoid pigments. Other colours are produced by combinations of melanophores, erythrophores, and iridocytes.

 

The major portion of the body of most fishes consists of muscles. Most of the mass is trunk musculature, the fin muscles usually being relatively small. The caudal fin is usually the most powerful fin, being moved by the trunk musculature. The body musculature is usually arranged in rows of chevron-shaped segments on each side. Contractions of these segments, each attached to adjacent vertebrae and vertebral processes, bends the body on the vertebral joint, producing successive undulations of the body, passing from the head to the tail, and producing driving strokes of the tail. It is the latter that provides the strong forward movement for most fishes.

 

The digestive system, in a functional sense, starts at the mouth, with the teeth used to capture prey or collect plant foods. Mouth shape and tooth structure vary greatly in fishes, depending on the kind of food normally eaten. Most fishes are predacious, feeding on small invertebrates or other fishes and have simple conical teeth on the jaws, on at least some of the bones of the roof of the mouth, and on special gill arch structures just in front of the esophagus. The latter are throat teeth. Most predacious fishes swallow their prey whole, and the teeth are used for grasping and holding prey, for orienting prey to be swallowed (head first) and for working the prey toward the esophagus. There are a variety of tooth types in fishes. Some fishes, such as sharks and piranhas, have cutting teeth for biting chunks out of their victims. A shark’s tooth, although superficially like that of a piranha, appears in many respects to be a modified scale, while that of the piranha is like that of other bony fishes, consisting of dentine and enamel. Parrot fishes have beaklike mouths with short incisor-like teeth for breaking off coral and have heavy pavementlike throat teeth for crushing the coral. Some catfishes have small brushlike teeth, arranged in rows on the jaws, for scraping plant and animal growth from rocks. Many fishes (such as the Cyprinidae or minnows) have no jaw teeth at all but have very strong throat teeth.

 

Some fishes gather planktonic food by straining it from their gill cavities with numerous elongate stiff rods (gill rakers) anchored by one end to the gill bars. The food collected on these rods is passed to the throat, where it is swallowed. Most fishes have only short gill rakers that help keep food particles from escaping out the mouth cavity into the gill chamber.

 

Once reaching the throat, food enters a short, often greatly distensible esophagus, a simple tube with a muscular wall leading into a stomach. The stomach varies greatly in fishes, depending upon the diet. In most predacious fishes it is a simple straight or curved tube or pouch with a muscular wall and a glandular lining. Food is largely digested there and leaves the stomach in liquid form.

 

Between the stomach and the intestine, ducts enter the digestive tube from the liver and pancreas. The liver is a large, clearly defined organ. The pancreas may be embedded in it, diffused through it, or broken into small parts spread along some of the intestine. The junction between the stomach and the intestine is marked by a muscular valve. Pyloric ceca (blind sacs) occur in some fishes at this junction and have a digestive or absorptive function or both.

 

The intestine itself is quite variable in length, depending upon the fish’s diet. It is short in predacious forms, sometimes no longer than the body cavity, but long in herbivorous forms, being coiled and several times longer than the entire length of the fish in some species of South American catfishes. The intestine is primarily an organ for absorbing nutrients into the bloodstream. The larger its internal surface, the greater its absorptive efficiency, and a spiral valve is one method of increasing its absorption surface.

 

Sharks, rays, chimaeras, lungfishes, surviving chondrosteans, holosteans, and even a few of the more primitive teleosts have a spiral valve or at least traces of it in the intestine. Most modern teleosts have increased the area of the intestinal walls by having numerous folds and villi (fingerlike projections) somewhat like those in humans. Undigested substances are passed to the exterior through the anus in most teleost fishes. In lungfishes, sharks, and rays, it is first passed through the cloaca, a common cavity receiving the intestinal opening and the ducts from the urogenital system.

 

Oxygen and carbon dioxide dissolve in water, and most fishes exchange dissolved oxygen and carbon dioxide in water by means of the gills. The gills lie behind and to the side of the mouth cavity and consist of fleshy filaments supported by the gill arches and filled with blood vessels, which give gills a bright red colour. Water taken in continuously through the mouth passes backward between the gill bars and over the gill filaments, where the exchange of gases takes place. The gills are protected by a gill cover in teleosts and many other fishes but by flaps of skin in sharks, rays, and some of the older fossil fish groups. The blood capillaries in the gill filaments are close to the gill surface to take up oxygen from the water and to give up excess carbon dioxide to the water.

 

Most modern fishes have a hydrostatic (ballast) organ, called the swim bladder, that lies in the body cavity just below the kidney and above the stomach and intestine. It originated as a diverticulum of the digestive canal. In advanced teleosts, especially the acanthopterygians, the bladder has lost its connection with the digestive tract, a condition called physoclistic. The connection has been retained (physostomous) by many relatively primitive teleosts. In several unrelated lines of fishes, the bladder has become specialized as a lung or, at least, as a highly vascularized accessory breathing organ. Some fishes with such accessory organs are obligate air breathers and will drown if denied access to the surface, even in well-oxygenated water. Fishes with a hydrostatic form of swim bladder can control their depth by regulating the amount of gas in the bladder. The gas, mostly oxygen, is secreted into the bladder by special glands, rendering the fish more buoyant; the gas is absorbed into the bloodstream by another special organ, reducing the overall buoyancy and allowing the fish to sink. Some deep-sea fishes may have oils, rather than gas, in the bladder. Other deep-sea and some bottom-living forms have much-reduced swim bladders or have lost the organ entirely.

 

The swim bladder of fishes follows the same developmental pattern as the lungs of land vertebrates. There is no doubt that the two structures have the same historical origin in primitive fishes. More or less intermediate forms still survive among the more primitive types of fishes, such as the lungfishes Lepidosiren and Protopterus.

 

The circulatory, or blood vascular, system consists of the heart, the arteries, the capillaries, and the veins. It is in the capillaries that the interchange of oxygen, carbon dioxide, nutrients, and other substances such as hormones and waste products takes place. The capillaries lead to the veins, which return the venous blood with its waste products to the heart, kidneys, and gills. There are two kinds of capillary beds: those in the gills and those in the rest of the body. The heart, a folded continuous muscular tube with three or four saclike enlargements, undergoes rhythmic contractions and receives venous blood in a sinus venosus. It passes the blood to an auricle and then into a thick muscular pump, the ventricle. From the ventricle the blood goes to a bulbous structure at the base of a ventral aorta just below the gills. The blood passes to the afferent (receiving) arteries of the gill arches and then to the gill capillaries. There waste gases are given off to the environment, and oxygen is absorbed. The oxygenated blood enters efferent (exuant) arteries of the gill arches and then flows into the dorsal aorta. From there blood is distributed to the tissues and organs of the body. One-way valves prevent backflow. The circulation of fishes thus differs from that of the reptiles, birds, and mammals in that oxygenated blood is not returned to the heart prior to distribution to the other parts of the body.

 

The primary excretory organ in fishes, as in other vertebrates, is the kidney. In fishes some excretion also takes place in the digestive tract, skin, and especially the gills (where ammonia is given off). Compared with land vertebrates, fishes have a special problem in maintaining their internal environment at a constant concentration of water and dissolved substances, such as salts. Proper balance of the internal environment (homeostasis) of a fish is in a great part maintained by the excretory system, especially the kidney.

 

The kidney, gills, and skin play an important role in maintaining a fish’s internal environment and checking the effects of osmosis. Marine fishes live in an environment in which the water around them has a greater concentration of salts than they can have inside their body and still maintain life. Freshwater fishes, on the other hand, live in water with a much lower concentration of salts than they require inside their bodies. Osmosis tends to promote the loss of water from the body of a marine fish and absorption of water by that of a freshwater fish. Mucus in the skin tends to slow the process but is not a sufficient barrier to prevent the movement of fluids through the permeable skin. When solutions on two sides of a permeable membrane have different concentrations of dissolved substances, water will pass through the membrane into the more concentrated solution, while the dissolved chemicals move into the area of lower concentration (diffusion).

 

The kidney of freshwater fishes is often larger in relation to body weight than that of marine fishes. In both groups the kidney excretes wastes from the body, but the kidney of freshwater fishes also excretes large amounts of water, counteracting the water absorbed through the skin. Freshwater fishes tend to lose salt to the environment and must replace it. They get some salt from their food, but the gills and skin inside the mouth actively absorb salt from water passed through the mouth. This absorption is performed by special cells capable of moving salts against the diffusion gradient. Freshwater fishes drink very little water and take in little water with their food.

 

Marine fishes must conserve water, and therefore their kidneys excrete little water. To maintain their water balance, marine fishes drink large quantities of seawater, retaining most of the water and excreting the salt. Most nitrogenous waste in marine fishes appears to be secreted by the gills as ammonia. Marine fishes can excrete salt by clusters of special cells (chloride cells) in the gills.

 

There are several teleosts—for example, the salmon—that travel between fresh water and seawater and must adjust to the reversal of osmotic gradients. They adjust their physiological processes by spending time (often surprisingly little time) in the intermediate brackish environment.

 

Marine hagfishes, sharks, and rays have osmotic concentrations in their blood about equal to that of seawater and so do not have to drink water nor perform much physiological work to maintain their osmotic balance. In sharks and rays the osmotic concentration is kept high by retention of urea in the blood. Freshwater sharks have a lowered concentration of urea in the blood.

 

Endocrine glands secrete their products into the bloodstream and body tissues and, along with the central nervous system, control and regulate many kinds of body functions. Cyclostomes have a well-developed endocrine system, and presumably it was well developed in the early Agnatha, ancestral to modern fishes. Although the endocrine system in fishes is similar to that of higher vertebrates, there are numerous differences in detail. The pituitary, the thyroid, the suprarenals, the adrenals, the pancreatic islets, the sex glands (ovaries and testes), the inner wall of the intestine, and the bodies of the ultimobranchial gland make up the endocrine system in fishes. There are some others whose function is not well understood. These organs regulate sexual activity and reproduction, growth, osmotic pressure, general metabolic activities such as the storage of fat and the utilization of foodstuffs, blood pressure, and certain aspects of skin colour. Many of these activities are also controlled in part by the central nervous system, which works with the endocrine system in maintaining the life of a fish. Some parts of the endocrine system are developmentally, and undoubtedly evolutionarily, derived from the nervous system.

 

As in all vertebrates, the nervous system of fishes is the primary mechanism coordinating body activities, as well as integrating these activities in the appropriate manner with stimuli from the environment. The central nervous system, consisting of the brain and spinal cord, is the primary integrating mechanism. The peripheral nervous system, consisting of nerves that connect the brain and spinal cord to various body organs, carries sensory information from special receptor organs such as the eyes, internal ears, nares (sense of smell), taste glands, and others to the integrating centres of the brain and spinal cord. The peripheral nervous system also carries information via different nerve cells from the integrating centres of the brain and spinal cord. This coded information is carried to the various organs and body systems, such as the skeletal muscular system, for appropriate action in response to the original external or internal stimulus. Another branch of the nervous system, the autonomic nervous system, helps to coordinate the activities of many glands and organs and is itself closely connected to the integrating centres of the brain.

 

The brain of the fish is divided into several anatomical and functional parts, all closely interconnected but each serving as the primary centre of integrating particular kinds of responses and activities. Several of these centres or parts are primarily associated with one type of sensory perception, such as sight, hearing, or smell (olfaction).

 

The sense of smell is important in almost all fishes. Certain eels with tiny eyes depend mostly on smell for location of food. The olfactory, or nasal, organ of fishes is located on the dorsal surface of the snout. The lining of the nasal organ has special sensory cells that perceive chemicals dissolved in the water, such as substances from food material, and send sensory information to the brain by way of the first cranial nerve. Odour also serves as an alarm system. Many fishes, especially various species of freshwater minnows, react with alarm to a chemical released from the skin of an injured member of their own species.

 

Many fishes have a well-developed sense of taste, and tiny pitlike taste buds or organs are located not only within their mouth cavities but also over their heads and parts of their body. Catfishes, which often have poor vision, have barbels (“whiskers”) that serve as supplementary taste organs, those around the mouth being actively used to search out food on the bottom. Some species of naturally blind cave fishes are especially well supplied with taste buds, which often cover most of their body surface.

 

Sight is extremely important in most fishes. The eye of a fish is basically like that of all other vertebrates, but the eyes of fishes are extremely varied in structure and adaptation. In general, fishes living in dark and dim water habitats have large eyes, unless they have specialized in some compensatory way so that another sense (such as smell) is dominant, in which case the eyes will often be reduced. Fishes living in brightly lighted shallow waters often will have relatively small but efficient eyes. Cyclostomes have somewhat less elaborate eyes than other fishes, with skin stretched over the eyeball perhaps making their vision somewhat less effective. Most fishes have a spherical lens and accommodate their vision to far or near subjects by moving the lens within the eyeball. A few sharks accommodate by changing the shape of the lens, as in land vertebrates. Those fishes that are heavily dependent upon the eyes have especially strong muscles for accommodation. Most fishes see well, despite the restrictions imposed by frequent turbidity of the water and by light refraction.

 

Fossil evidence suggests that colour vision evolved in fishes more than 300 million years ago, but not all living fishes have retained this ability. Experimental evidence indicates that many shallow-water fishes, if not all, have colour vision and see some colours especially well, but some bottom-dwelling shore fishes live in areas where the water is sufficiently deep to filter out most if not all colours, and these fishes apparently never see colours. When tested in shallow water, they apparently are unable to respond to colour differences.

 

Sound perception and balance are intimately associated senses in a fish. The organs of hearing are entirely internal, located within the skull, on each side of the brain and somewhat behind the eyes. Sound waves, especially those of low frequencies, travel readily through water and impinge directly upon the bones and fluids of the head and body, to be transmitted to the hearing organs. Fishes readily respond to sound; for example, a trout conditioned to escape by the approach of fishermen will take flight upon perceiving footsteps on a stream bank even if it cannot see a fisherman. Compared with humans, however, the range of sound frequencies heard by fishes is greatly restricted. Many fishes communicate with each other by producing sounds in their swim bladders, in their throats by rasping their teeth, and in other ways.

 

A fish or other vertebrate seldom has to rely on a single type of sensory information to determine the nature of the environment around it. A catfish uses taste and touch when examining a food object with its oral barbels. Like most other animals, fishes have many touch receptors over their body surface. Pain and temperature receptors also are present in fishes and presumably produce the same kind of information to a fish as to humans. Fishes react in a negative fashion to stimuli that would be painful to human beings, suggesting that they feel a sensation of pain.

 

An important sensory system in fishes that is absent in other vertebrates (except some amphibians) is the lateral line system. This consists of a series of heavily innervated small canals located in the skin and bone around the eyes, along the lower jaw, over the head, and down the mid-side of the body, where it is associated with the scales. Intermittently along these canals are located tiny sensory organs (pit organs) that apparently detect changes in pressure. The system allows a fish to sense changes in water currents and pressure, thereby helping the fish to orient itself to the various changes that occur in the physical environment.

  

Can you believe I'm working in this stunning building this year? For my Honours year I'm researching changes in the endocrine synapse and their impact in diabetes.

Fish, any of approximately 34,000 species of vertebrate animals (phylum Chordata) found in the fresh and salt waters of the world. Living species range from the primitive jawless lampreys and hagfishes through the cartilaginous sharks, skates, and rays to the abundant and diverse bony fishes. Most fish species are cold-blooded; however, one species, the opah (Lampris guttatus), is warm-blooded.

 

The term fish is applied to a variety of vertebrates of several evolutionary lines. It describes a life-form rather than a taxonomic group. As members of the phylum Chordata, fish share certain features with other vertebrates. These features are gill slits at some point in the life cycle, a notochord, or skeletal supporting rod, a dorsal hollow nerve cord, and a tail. Living fishes represent some five classes, which are as distinct from one another as are the four classes of familiar air-breathing animals—amphibians, reptiles, birds, and mammals. For example, the jawless fishes (Agnatha) have gills in pouches and lack limb girdles. Extant agnathans are the lampreys and the hagfishes. As the name implies, the skeletons of fishes of the class Chondrichthyes (from chondr, “cartilage,” and ichthyes, “fish”) are made entirely of cartilage. Modern fish of this class lack a swim bladder, and their scales and teeth are made up of the same placoid material. Sharks, skates, and rays are examples of cartilaginous fishes. The bony fishes are by far the largest class. Examples range from the tiny seahorse to the 450-kg (1,000-pound) blue marlin, from the flattened soles and flounders to the boxy puffers and ocean sunfishes. Unlike the scales of the cartilaginous fishes, those of bony fishes, when present, grow throughout life and are made up of thin overlapping plates of bone. Bony fishes also have an operculum that covers the gill slits.

 

The study of fishes, the science of ichthyology, is of broad importance. Fishes are of interest to humans for many reasons, the most important being their relationship with and dependence on the environment. A more obvious reason for interest in fishes is their role as a moderate but important part of the world’s food supply. This resource, once thought unlimited, is now realized to be finite and in delicate balance with the biological, chemical, and physical factors of the aquatic environment. Overfishing, pollution, and alteration of the environment are the chief enemies of proper fisheries management, both in fresh waters and in the ocean. (For a detailed discussion of the technology and economics of fisheries, see commercial fishing.) Another practical reason for studying fishes is their use in disease control. As predators on mosquito larvae, they help curb malaria and other mosquito-borne diseases.

 

Fishes are valuable laboratory animals in many aspects of medical and biological research. For example, the readiness of many fishes to acclimate to captivity has allowed biologists to study behaviour, physiology, and even ecology under relatively natural conditions. Fishes have been especially important in the study of animal behaviour, where research on fishes has provided a broad base for the understanding of the more flexible behaviour of the higher vertebrates. The zebra fish is used as a model in studies of gene expression.

 

There are aesthetic and recreational reasons for an interest in fishes. Millions of people keep live fishes in home aquariums for the simple pleasure of observing the beauty and behaviour of animals otherwise unfamiliar to them. Aquarium fishes provide a personal challenge to many aquarists, allowing them to test their ability to keep a small section of the natural environment in their homes. Sportfishing is another way of enjoying the natural environment, also indulged in by millions of people every year. Interest in aquarium fishes and sportfishing supports multimillion-dollar industries throughout the world.

 

Fishes have been in existence for more than 450 million years, during which time they have evolved repeatedly to fit into almost every conceivable type of aquatic habitat. In a sense, land vertebrates are simply highly modified fishes: when fishes colonized the land habitat, they became tetrapod (four-legged) land vertebrates. The popular conception of a fish as a slippery, streamlined aquatic animal that possesses fins and breathes by gills applies to many fishes, but far more fishes deviate from that conception than conform to it. For example, the body is elongate in many forms and greatly shortened in others; the body is flattened in some (principally in bottom-dwelling fishes) and laterally compressed in many others; the fins may be elaborately extended, forming intricate shapes, or they may be reduced or even lost; and the positions of the mouth, eyes, nostrils, and gill openings vary widely. Air breathers have appeared in several evolutionary lines.

 

Many fishes are cryptically coloured and shaped, closely matching their respective environments; others are among the most brilliantly coloured of all organisms, with a wide range of hues, often of striking intensity, on a single individual. The brilliance of pigments may be enhanced by the surface structure of the fish, so that it almost seems to glow. A number of unrelated fishes have actual light-producing organs. Many fishes are able to alter their coloration—some for the purpose of camouflage, others for the enhancement of behavioral signals.

 

Fishes range in adult length from less than 10 mm (0.4 inch) to more than 20 metres (60 feet) and in weight from about 1.5 grams (less than 0.06 ounce) to many thousands of kilograms. Some live in shallow thermal springs at temperatures slightly above 42 °C (100 °F), others in cold Arctic seas a few degrees below 0 °C (32 °F) or in cold deep waters more than 4,000 metres (13,100 feet) beneath the ocean surface. The structural and, especially, the physiological adaptations for life at such extremes are relatively poorly known and provide the scientifically curious with great incentive for study.

 

Almost all natural bodies of water bear fish life, the exceptions being very hot thermal ponds and extremely salt-alkaline lakes, such as the Dead Sea in Asia and the Great Salt Lake in North America. The present distribution of fishes is a result of the geological history and development of Earth as well as the ability of fishes to undergo evolutionary change and to adapt to the available habitats. Fishes may be seen to be distributed according to habitat and according to geographical area. Major habitat differences are marine and freshwater. For the most part, the fishes in a marine habitat differ from those in a freshwater habitat, even in adjacent areas, but some, such as the salmon, migrate from one to the other. The freshwater habitats may be seen to be of many kinds. Fishes found in mountain torrents, Arctic lakes, tropical lakes, temperate streams, and tropical rivers will all differ from each other, both in obvious gross structure and in physiological attributes. Even in closely adjacent habitats where, for example, a tropical mountain torrent enters a lowland stream, the fish fauna will differ. The marine habitats can be divided into deep ocean floors (benthic), mid-water oceanic (bathypelagic), surface oceanic (pelagic), rocky coast, sandy coast, muddy shores, bays, estuaries, and others. Also, for example, rocky coastal shores in tropical and temperate regions will have different fish faunas, even when such habitats occur along the same coastline.

 

Although much is known about the present geographical distribution of fishes, far less is known about how that distribution came about. Many parts of the fish fauna of the fresh waters of North America and Eurasia are related and undoubtedly have a common origin. The faunas of Africa and South America are related, extremely old, and probably an expression of the drifting apart of the two continents. The fauna of southern Asia is related to that of Central Asia, and some of it appears to have entered Africa. The extremely large shore-fish faunas of the Indian and tropical Pacific oceans comprise a related complex, but the tropical shore fauna of the Atlantic, although containing Indo-Pacific components, is relatively limited and probably younger. The Arctic and Antarctic marine faunas are quite different from each other. The shore fauna of the North Pacific is quite distinct, and that of the North Atlantic more limited and probably younger. Pelagic oceanic fishes, especially those in deep waters, are similar the world over, showing little geographical isolation in terms of family groups. The deep oceanic habitat is very much the same throughout the world, but species differences do exist, showing geographical areas determined by oceanic currents and water masses.

 

All aspects of the life of a fish are closely correlated with adaptation to the total environment, physical, chemical, and biological. In studies, all the interdependent aspects of fish, such as behaviour, locomotion, reproduction, and physical and physiological characteristics, must be taken into account.

 

Correlated with their adaptation to an extremely wide variety of habitats is the extremely wide variety of life cycles that fishes display. The great majority hatch from relatively small eggs a few days to several weeks or more after the eggs are scattered in the water. Newly hatched young are still partially undeveloped and are called larvae until body structures such as fins, skeleton, and some organs are fully formed. Larval life is often very short, usually less than a few weeks, but it can be very long, some lampreys continuing as larvae for at least five years. Young and larval fishes, before reaching sexual maturity, must grow considerably, and their small size and other factors often dictate that they live in a habitat different than that of the adults. For example, most tropical marine shore fishes have pelagic larvae. Larval food also is different, and larval fishes often live in shallow waters, where they may be less exposed to predators.

 

After a fish reaches adult size, the length of its life is subject to many factors, such as innate rates of aging, predation pressure, and the nature of the local climate. The longevity of a species in the protected environment of an aquarium may have nothing to do with how long members of that species live in the wild. Many small fishes live only one to three years at the most. In some species, however, individuals may live as long as 10 or 20 or even 100 years.

 

Fish behaviour is a complicated and varied subject. As in almost all animals with a central nervous system, the nature of a response of an individual fish to stimuli from its environment depends upon the inherited characteristics of its nervous system, on what it has learned from past experience, and on the nature of the stimuli. Compared with the variety of human responses, however, that of a fish is stereotyped, not subject to much modification by “thought” or learning, and investigators must guard against anthropomorphic interpretations of fish behaviour.

 

Fishes perceive the world around them by the usual senses of sight, smell, hearing, touch, and taste and by special lateral line water-current detectors. In the few fishes that generate electric fields, a process that might best be called electrolocation aids in perception. One or another of these senses often is emphasized at the expense of others, depending upon the fish’s other adaptations. In fishes with large eyes, the sense of smell may be reduced; others, with small eyes, hunt and feed primarily by smell (such as some eels).

 

Specialized behaviour is primarily concerned with the three most important activities in the fish’s life: feeding, reproduction, and escape from enemies. Schooling behaviour of sardines on the high seas, for instance, is largely a protective device to avoid enemies, but it is also associated with and modified by their breeding and feeding requirements. Predatory fishes are often solitary, lying in wait to dart suddenly after their prey, a kind of locomotion impossible for beaked parrot fishes, which feed on coral, swimming in small groups from one coral head to the next. In addition, some predatory fishes that inhabit pelagic environments, such as tunas, often school.

 

Sleep in fishes, all of which lack true eyelids, consists of a seemingly listless state in which the fish maintains its balance but moves slowly. If attacked or disturbed, most can dart away. A few kinds of fishes lie on the bottom to sleep. Most catfishes, some loaches, and some eels and electric fishes are strictly nocturnal, being active and hunting for food during the night and retiring during the day to holes, thick vegetation, or other protective parts of the environment.

 

Communication between members of a species or between members of two or more species often is extremely important, especially in breeding behaviour (see below Reproduction). The mode of communication may be visual, as between the small so-called cleaner fish and a large fish of a very different species. The larger fish often allows the cleaner to enter its mouth to remove gill parasites. The cleaner is recognized by its distinctive colour and actions and therefore is not eaten, even if the larger fish is normally a predator. Communication is often chemical, signals being sent by specific chemicals called pheromones.

 

Many fishes have a streamlined body and swim freely in open water. Fish locomotion is closely correlated with habitat and ecological niche (the general position of the animal to its environment).

 

Many fishes in both marine and fresh waters swim at the surface and have mouths adapted to feed best (and sometimes only) at the surface. Often such fishes are long and slender, able to dart at surface insects or at other surface fishes and in turn to dart away from predators; needlefishes, halfbeaks, and topminnows (such as killifish and mosquito fish) are good examples. Oceanic flying fishes escape their predators by gathering speed above the water surface, with the lower lobe of the tail providing thrust in the water. They then glide hundreds of yards on enlarged, winglike pectoral and pelvic fins. South American freshwater flying fishes escape their enemies by jumping and propelling their strongly keeled bodies out of the water.

 

So-called mid-water swimmers, the most common type of fish, are of many kinds and live in many habitats. The powerful fusiform tunas and the trouts, for example, are adapted for strong, fast swimming, the tunas to capture prey speedily in the open ocean and the trouts to cope with the swift currents of streams and rivers. The trout body form is well adapted to many habitats. Fishes that live in relatively quiet waters such as bays or lake shores or slow rivers usually are not strong, fast swimmers but are capable of short, quick bursts of speed to escape a predator. Many of these fishes have their sides flattened, examples being the sunfish and the freshwater angelfish of aquarists. Fish associated with the bottom or substrate usually are slow swimmers. Open-water plankton-feeding fishes almost always remain fusiform and are capable of rapid, strong movement (for example, sardines and herrings of the open ocean and also many small minnows of streams and lakes).

 

Bottom-living fishes are of many kinds and have undergone many types of modification of their body shape and swimming habits. Rays, which evolved from strong-swimming mid-water sharks, usually stay close to the bottom and move by undulating their large pectoral fins. Flounders live in a similar habitat and move over the bottom by undulating the entire body. Many bottom fishes dart from place to place, resting on the bottom between movements, a motion common in gobies. One goby relative, the mudskipper, has taken to living at the edge of pools along the shore of muddy mangrove swamps. It escapes its enemies by flipping rapidly over the mud, out of the water. Some catfishes, synbranchid eels, the so-called climbing perch, and a few other fishes venture out over damp ground to find more promising waters than those that they left. They move by wriggling their bodies, sometimes using strong pectoral fins; most have accessory air-breathing organs. Many bottom-dwelling fishes live in mud holes or rocky crevices. Marine eels and gobies commonly are found in such habitats and for the most part venture far beyond their cavelike homes. Some bottom dwellers, such as the clingfishes (Gobiesocidae), have developed powerful adhesive disks that enable them to remain in place on the substrate in areas such as rocky coasts, where the action of the waves is great.

 

The methods of reproduction in fishes are varied, but most fishes lay a large number of small eggs, fertilized and scattered outside of the body. The eggs of pelagic fishes usually remain suspended in the open water. Many shore and freshwater fishes lay eggs on the bottom or among plants. Some have adhesive eggs. The mortality of the young and especially of the eggs is very high, and often only a few individuals grow to maturity out of hundreds, thousands, and in some cases millions of eggs laid.

 

Males produce sperm, usually as a milky white substance called milt, in two (sometimes one) testes within the body cavity. In bony fishes a sperm duct leads from each testis to a urogenital opening behind the vent or anus. In sharks and rays and in cyclostomes the duct leads to a cloaca. Sometimes the pelvic fins are modified to help transmit the milt to the eggs at the female’s vent or on the substrate where the female has placed them. Sometimes accessory organs are used to fertilize females internally—for example, the claspers of many sharks and rays.

 

In the females the eggs are formed in two ovaries (sometimes only one) and pass through the ovaries to the urogenital opening and to the outside. In some fishes the eggs are fertilized internally but are shed before development takes place. Members of about a dozen families each of bony fishes (teleosts) and sharks bear live young. Many skates and rays also bear live young. In some bony fishes the eggs simply develop within the female, the young emerging when the eggs hatch (ovoviviparous). Others develop within the ovary and are nourished by ovarian tissues after hatching (viviparous). There are also other methods utilized by fishes to nourish young within the female. In all live-bearers the young are born at a relatively large size and are few in number. In one family of primarily marine fishes, the surfperches from the Pacific coast of North America, Japan, and Korea, the males of at least one species are born sexually mature, although they are not fully grown.

 

Some fishes are hermaphroditic—an individual producing both sperm and eggs, usually at different stages of its life. Self-fertilization, however, is probably rare.

 

Successful reproduction and, in many cases, defense of the eggs and the young are assured by rather stereotypical but often elaborate courtship and parental behaviour, either by the male or the female or both. Some fishes prepare nests by hollowing out depressions in the sand bottom (cichlids, for example), build nests with plant materials and sticky threads excreted by the kidneys (sticklebacks), or blow a cluster of mucus-covered bubbles at the water surface (gouramis). The eggs are laid in these structures. Some varieties of cichlids and catfishes incubate eggs in their mouths.

 

Some fishes, such as salmon, undergo long migrations from the ocean and up large rivers to spawn in the gravel beds where they themselves hatched (anadromous fishes). Some, such as the freshwater eels (family Anguillidae), live and grow to maturity in fresh water and migrate to the sea to spawn (catadromous fishes). Other fishes undertake shorter migrations from lakes into streams, within the ocean, or enter spawning habitats that they do not ordinarily occupy in other ways.

 

The basic structure and function of the fish body are similar to those of all other vertebrates. The usual four types of tissues are present: surface or epithelial, connective (bone, cartilage, and fibrous tissues, as well as their derivative, blood), nerve, and muscle tissues. In addition, the fish’s organs and organ systems parallel those of other vertebrates.

 

The typical fish body is streamlined and spindle-shaped, with an anterior head, a gill apparatus, and a heart, the latter lying in the midline just below the gill chamber. The body cavity, containing the vital organs, is situated behind the head in the lower anterior part of the body. The anus usually marks the posterior termination of the body cavity and most often occurs just in front of the base of the anal fin. The spinal cord and vertebral column continue from the posterior part of the head to the base of the tail fin, passing dorsal to the body cavity and through the caudal (tail) region behind the body cavity. Most of the body is of muscular tissue, a high proportion of which is necessitated by swimming. In the course of evolution this basic body plan has been modified repeatedly into the many varieties of fish shapes that exist today.

 

The skeleton forms an integral part of the fish’s locomotion system, as well as serving to protect vital parts. The internal skeleton consists of the skull bones (except for the roofing bones of the head, which are really part of the external skeleton), the vertebral column, and the fin supports (fin rays). The fin supports are derived from the external skeleton but will be treated here because of their close functional relationship to the internal skeleton. The internal skeleton of cyclostomes, sharks, and rays is of cartilage; that of many fossil groups and some primitive living fishes is mostly of cartilage but may include some bone. In place of the vertebral column, the earliest vertebrates had a fully developed notochord, a flexible stiff rod of viscous cells surrounded by a strong fibrous sheath. During the evolution of modern fishes the rod was replaced in part by cartilage and then by ossified cartilage. Sharks and rays retain a cartilaginous vertebral column; bony fishes have spool-shaped vertebrae that in the more primitive living forms only partially replace the notochord. The skull, including the gill arches and jaws of bony fishes, is fully, or at least partially, ossified. That of sharks and rays remains cartilaginous, at times partially replaced by calcium deposits but never by true bone.

 

The supportive elements of the fins (basal or radial bones or both) have changed greatly during fish evolution. Some of these changes are described in the section below (Evolution and paleontology). Most fishes possess a single dorsal fin on the midline of the back. Many have two and a few have three dorsal fins. The other fins are the single tail and anal fins and paired pelvic and pectoral fins. A small fin, the adipose fin, with hairlike fin rays, occurs in many of the relatively primitive teleosts (such as trout) on the back near the base of the caudal fin.

 

The skin of a fish must serve many functions. It aids in maintaining the osmotic balance, provides physical protection for the body, is the site of coloration, contains sensory receptors, and, in some fishes, functions in respiration. Mucous glands, which aid in maintaining the water balance and offer protection from bacteria, are extremely numerous in fish skin, especially in cyclostomes and teleosts. Since mucous glands are present in the modern lampreys, it is reasonable to assume that they were present in primitive fishes, such as the ancient Silurian and Devonian agnathans. Protection from abrasion and predation is another function of the fish skin, and dermal (skin) bone arose early in fish evolution in response to this need. It is thought that bone first evolved in skin and only later invaded the cartilaginous areas of the fish’s body, to provide additional support and protection. There is some argument as to which came first, cartilage or bone, and fossil evidence does not settle the question. In any event, dermal bone has played an important part in fish evolution and has different characteristics in different groups of fishes. Several groups are characterized at least in part by the kind of bony scales they possess.

 

Scales have played an important part in the evolution of fishes. Primitive fishes usually had thick bony plates or thick scales in several layers of bone, enamel, and related substances. Modern teleost fishes have scales of bone, which, while still protective, allow much more freedom of motion in the body. A few modern teleosts (some catfishes, sticklebacks, and others) have secondarily acquired bony plates in the skin. Modern and early sharks possessed placoid scales, a relatively primitive type of scale with a toothlike structure, consisting of an outside layer of enamel-like substance (vitrodentine), an inner layer of dentine, and a pulp cavity containing nerves and blood vessels. Primitive bony fishes had thick scales of either the ganoid or the cosmoid type. Cosmoid scales have a hard, enamel-like outer layer, an inner layer of cosmine (a form of dentine), and then a layer of vascular bone (isopedine). In ganoid scales the hard outer layer is different chemically and is called ganoin. Under this is a cosminelike layer and then a vascular bony layer. The thin, translucent bony scales of modern fishes, called cycloid and ctenoid (the latter distinguished by serrations at the edges), lack enameloid and dentine layers.

 

Skin has several other functions in fishes. It is well supplied with nerve endings and presumably receives tactile, thermal, and pain stimuli. Skin is also well supplied with blood vessels. Some fishes breathe in part through the skin, by the exchange of oxygen and carbon dioxide between the surrounding water and numerous small blood vessels near the skin surface.

 

Skin serves as protection through the control of coloration. Fishes exhibit an almost limitless range of colours. The colours often blend closely with the surroundings, effectively hiding the animal. Many fishes use bright colours for territorial advertisement or as recognition marks for other members of their own species, or sometimes for members of other species. Many fishes can change their colour to a greater or lesser degree, by movement of pigment within the pigment cells (chromatophores). Black pigment cells (melanophores), of almost universal occurrence in fishes, are often juxtaposed with other pigment cells. When placed beneath iridocytes or leucophores (bearing the silvery or white pigment guanine), melanophores produce structural colours of blue and green. These colours are often extremely intense, because they are formed by refraction of light through the needlelike crystals of guanine. The blue and green refracted colours are often relatively pure, lacking the red and yellow rays, which have been absorbed by the black pigment (melanin) of the melanophores. Yellow, orange, and red colours are produced by erythrophores, cells containing the appropriate carotenoid pigments. Other colours are produced by combinations of melanophores, erythrophores, and iridocytes.

 

The major portion of the body of most fishes consists of muscles. Most of the mass is trunk musculature, the fin muscles usually being relatively small. The caudal fin is usually the most powerful fin, being moved by the trunk musculature. The body musculature is usually arranged in rows of chevron-shaped segments on each side. Contractions of these segments, each attached to adjacent vertebrae and vertebral processes, bends the body on the vertebral joint, producing successive undulations of the body, passing from the head to the tail, and producing driving strokes of the tail. It is the latter that provides the strong forward movement for most fishes.

 

The digestive system, in a functional sense, starts at the mouth, with the teeth used to capture prey or collect plant foods. Mouth shape and tooth structure vary greatly in fishes, depending on the kind of food normally eaten. Most fishes are predacious, feeding on small invertebrates or other fishes and have simple conical teeth on the jaws, on at least some of the bones of the roof of the mouth, and on special gill arch structures just in front of the esophagus. The latter are throat teeth. Most predacious fishes swallow their prey whole, and the teeth are used for grasping and holding prey, for orienting prey to be swallowed (head first) and for working the prey toward the esophagus. There are a variety of tooth types in fishes. Some fishes, such as sharks and piranhas, have cutting teeth for biting chunks out of their victims. A shark’s tooth, although superficially like that of a piranha, appears in many respects to be a modified scale, while that of the piranha is like that of other bony fishes, consisting of dentine and enamel. Parrot fishes have beaklike mouths with short incisor-like teeth for breaking off coral and have heavy pavementlike throat teeth for crushing the coral. Some catfishes have small brushlike teeth, arranged in rows on the jaws, for scraping plant and animal growth from rocks. Many fishes (such as the Cyprinidae or minnows) have no jaw teeth at all but have very strong throat teeth.

 

Some fishes gather planktonic food by straining it from their gill cavities with numerous elongate stiff rods (gill rakers) anchored by one end to the gill bars. The food collected on these rods is passed to the throat, where it is swallowed. Most fishes have only short gill rakers that help keep food particles from escaping out the mouth cavity into the gill chamber.

 

Once reaching the throat, food enters a short, often greatly distensible esophagus, a simple tube with a muscular wall leading into a stomach. The stomach varies greatly in fishes, depending upon the diet. In most predacious fishes it is a simple straight or curved tube or pouch with a muscular wall and a glandular lining. Food is largely digested there and leaves the stomach in liquid form.

 

Between the stomach and the intestine, ducts enter the digestive tube from the liver and pancreas. The liver is a large, clearly defined organ. The pancreas may be embedded in it, diffused through it, or broken into small parts spread along some of the intestine. The junction between the stomach and the intestine is marked by a muscular valve. Pyloric ceca (blind sacs) occur in some fishes at this junction and have a digestive or absorptive function or both.

 

The intestine itself is quite variable in length, depending upon the fish’s diet. It is short in predacious forms, sometimes no longer than the body cavity, but long in herbivorous forms, being coiled and several times longer than the entire length of the fish in some species of South American catfishes. The intestine is primarily an organ for absorbing nutrients into the bloodstream. The larger its internal surface, the greater its absorptive efficiency, and a spiral valve is one method of increasing its absorption surface.

 

Sharks, rays, chimaeras, lungfishes, surviving chondrosteans, holosteans, and even a few of the more primitive teleosts have a spiral valve or at least traces of it in the intestine. Most modern teleosts have increased the area of the intestinal walls by having numerous folds and villi (fingerlike projections) somewhat like those in humans. Undigested substances are passed to the exterior through the anus in most teleost fishes. In lungfishes, sharks, and rays, it is first passed through the cloaca, a common cavity receiving the intestinal opening and the ducts from the urogenital system.

 

Oxygen and carbon dioxide dissolve in water, and most fishes exchange dissolved oxygen and carbon dioxide in water by means of the gills. The gills lie behind and to the side of the mouth cavity and consist of fleshy filaments supported by the gill arches and filled with blood vessels, which give gills a bright red colour. Water taken in continuously through the mouth passes backward between the gill bars and over the gill filaments, where the exchange of gases takes place. The gills are protected by a gill cover in teleosts and many other fishes but by flaps of skin in sharks, rays, and some of the older fossil fish groups. The blood capillaries in the gill filaments are close to the gill surface to take up oxygen from the water and to give up excess carbon dioxide to the water.

 

Most modern fishes have a hydrostatic (ballast) organ, called the swim bladder, that lies in the body cavity just below the kidney and above the stomach and intestine. It originated as a diverticulum of the digestive canal. In advanced teleosts, especially the acanthopterygians, the bladder has lost its connection with the digestive tract, a condition called physoclistic. The connection has been retained (physostomous) by many relatively primitive teleosts. In several unrelated lines of fishes, the bladder has become specialized as a lung or, at least, as a highly vascularized accessory breathing organ. Some fishes with such accessory organs are obligate air breathers and will drown if denied access to the surface, even in well-oxygenated water. Fishes with a hydrostatic form of swim bladder can control their depth by regulating the amount of gas in the bladder. The gas, mostly oxygen, is secreted into the bladder by special glands, rendering the fish more buoyant; the gas is absorbed into the bloodstream by another special organ, reducing the overall buoyancy and allowing the fish to sink. Some deep-sea fishes may have oils, rather than gas, in the bladder. Other deep-sea and some bottom-living forms have much-reduced swim bladders or have lost the organ entirely.

 

The swim bladder of fishes follows the same developmental pattern as the lungs of land vertebrates. There is no doubt that the two structures have the same historical origin in primitive fishes. More or less intermediate forms still survive among the more primitive types of fishes, such as the lungfishes Lepidosiren and Protopterus.

 

The circulatory, or blood vascular, system consists of the heart, the arteries, the capillaries, and the veins. It is in the capillaries that the interchange of oxygen, carbon dioxide, nutrients, and other substances such as hormones and waste products takes place. The capillaries lead to the veins, which return the venous blood with its waste products to the heart, kidneys, and gills. There are two kinds of capillary beds: those in the gills and those in the rest of the body. The heart, a folded continuous muscular tube with three or four saclike enlargements, undergoes rhythmic contractions and receives venous blood in a sinus venosus. It passes the blood to an auricle and then into a thick muscular pump, the ventricle. From the ventricle the blood goes to a bulbous structure at the base of a ventral aorta just below the gills. The blood passes to the afferent (receiving) arteries of the gill arches and then to the gill capillaries. There waste gases are given off to the environment, and oxygen is absorbed. The oxygenated blood enters efferent (exuant) arteries of the gill arches and then flows into the dorsal aorta. From there blood is distributed to the tissues and organs of the body. One-way valves prevent backflow. The circulation of fishes thus differs from that of the reptiles, birds, and mammals in that oxygenated blood is not returned to the heart prior to distribution to the other parts of the body.

 

The primary excretory organ in fishes, as in other vertebrates, is the kidney. In fishes some excretion also takes place in the digestive tract, skin, and especially the gills (where ammonia is given off). Compared with land vertebrates, fishes have a special problem in maintaining their internal environment at a constant concentration of water and dissolved substances, such as salts. Proper balance of the internal environment (homeostasis) of a fish is in a great part maintained by the excretory system, especially the kidney.

 

The kidney, gills, and skin play an important role in maintaining a fish’s internal environment and checking the effects of osmosis. Marine fishes live in an environment in which the water around them has a greater concentration of salts than they can have inside their body and still maintain life. Freshwater fishes, on the other hand, live in water with a much lower concentration of salts than they require inside their bodies. Osmosis tends to promote the loss of water from the body of a marine fish and absorption of water by that of a freshwater fish. Mucus in the skin tends to slow the process but is not a sufficient barrier to prevent the movement of fluids through the permeable skin. When solutions on two sides of a permeable membrane have different concentrations of dissolved substances, water will pass through the membrane into the more concentrated solution, while the dissolved chemicals move into the area of lower concentration (diffusion).

 

The kidney of freshwater fishes is often larger in relation to body weight than that of marine fishes. In both groups the kidney excretes wastes from the body, but the kidney of freshwater fishes also excretes large amounts of water, counteracting the water absorbed through the skin. Freshwater fishes tend to lose salt to the environment and must replace it. They get some salt from their food, but the gills and skin inside the mouth actively absorb salt from water passed through the mouth. This absorption is performed by special cells capable of moving salts against the diffusion gradient. Freshwater fishes drink very little water and take in little water with their food.

 

Marine fishes must conserve water, and therefore their kidneys excrete little water. To maintain their water balance, marine fishes drink large quantities of seawater, retaining most of the water and excreting the salt. Most nitrogenous waste in marine fishes appears to be secreted by the gills as ammonia. Marine fishes can excrete salt by clusters of special cells (chloride cells) in the gills.

 

There are several teleosts—for example, the salmon—that travel between fresh water and seawater and must adjust to the reversal of osmotic gradients. They adjust their physiological processes by spending time (often surprisingly little time) in the intermediate brackish environment.

 

Marine hagfishes, sharks, and rays have osmotic concentrations in their blood about equal to that of seawater and so do not have to drink water nor perform much physiological work to maintain their osmotic balance. In sharks and rays the osmotic concentration is kept high by retention of urea in the blood. Freshwater sharks have a lowered concentration of urea in the blood.

 

Endocrine glands secrete their products into the bloodstream and body tissues and, along with the central nervous system, control and regulate many kinds of body functions. Cyclostomes have a well-developed endocrine system, and presumably it was well developed in the early Agnatha, ancestral to modern fishes. Although the endocrine system in fishes is similar to that of higher vertebrates, there are numerous differences in detail. The pituitary, the thyroid, the suprarenals, the adrenals, the pancreatic islets, the sex glands (ovaries and testes), the inner wall of the intestine, and the bodies of the ultimobranchial gland make up the endocrine system in fishes. There are some others whose function is not well understood. These organs regulate sexual activity and reproduction, growth, osmotic pressure, general metabolic activities such as the storage of fat and the utilization of foodstuffs, blood pressure, and certain aspects of skin colour. Many of these activities are also controlled in part by the central nervous system, which works with the endocrine system in maintaining the life of a fish. Some parts of the endocrine system are developmentally, and undoubtedly evolutionarily, derived from the nervous system.

 

As in all vertebrates, the nervous system of fishes is the primary mechanism coordinating body activities, as well as integrating these activities in the appropriate manner with stimuli from the environment. The central nervous system, consisting of the brain and spinal cord, is the primary integrating mechanism. The peripheral nervous system, consisting of nerves that connect the brain and spinal cord to various body organs, carries sensory information from special receptor organs such as the eyes, internal ears, nares (sense of smell), taste glands, and others to the integrating centres of the brain and spinal cord. The peripheral nervous system also carries information via different nerve cells from the integrating centres of the brain and spinal cord. This coded information is carried to the various organs and body systems, such as the skeletal muscular system, for appropriate action in response to the original external or internal stimulus. Another branch of the nervous system, the autonomic nervous system, helps to coordinate the activities of many glands and organs and is itself closely connected to the integrating centres of the brain.

 

The brain of the fish is divided into several anatomical and functional parts, all closely interconnected but each serving as the primary centre of integrating particular kinds of responses and activities. Several of these centres or parts are primarily associated with one type of sensory perception, such as sight, hearing, or smell (olfaction).

 

The sense of smell is important in almost all fishes. Certain eels with tiny eyes depend mostly on smell for location of food. The olfactory, or nasal, organ of fishes is located on the dorsal surface of the snout. The lining of the nasal organ has special sensory cells that perceive chemicals dissolved in the water, such as substances from food material, and send sensory information to the brain by way of the first cranial nerve. Odour also serves as an alarm system. Many fishes, especially various species of freshwater minnows, react with alarm to a chemical released from the skin of an injured member of their own species.

 

Many fishes have a well-developed sense of taste, and tiny pitlike taste buds or organs are located not only within their mouth cavities but also over their heads and parts of their body. Catfishes, which often have poor vision, have barbels (“whiskers”) that serve as supplementary taste organs, those around the mouth being actively used to search out food on the bottom. Some species of naturally blind cave fishes are especially well supplied with taste buds, which often cover most of their body surface.

 

Sight is extremely important in most fishes. The eye of a fish is basically like that of all other vertebrates, but the eyes of fishes are extremely varied in structure and adaptation. In general, fishes living in dark and dim water habitats have large eyes, unless they have specialized in some compensatory way so that another sense (such as smell) is dominant, in which case the eyes will often be reduced. Fishes living in brightly lighted shallow waters often will have relatively small but efficient eyes. Cyclostomes have somewhat less elaborate eyes than other fishes, with skin stretched over the eyeball perhaps making their vision somewhat less effective. Most fishes have a spherical lens and accommodate their vision to far or near subjects by moving the lens within the eyeball. A few sharks accommodate by changing the shape of the lens, as in land vertebrates. Those fishes that are heavily dependent upon the eyes have especially strong muscles for accommodation. Most fishes see well, despite the restrictions imposed by frequent turbidity of the water and by light refraction.

 

Fossil evidence suggests that colour vision evolved in fishes more than 300 million years ago, but not all living fishes have retained this ability. Experimental evidence indicates that many shallow-water fishes, if not all, have colour vision and see some colours especially well, but some bottom-dwelling shore fishes live in areas where the water is sufficiently deep to filter out most if not all colours, and these fishes apparently never see colours. When tested in shallow water, they apparently are unable to respond to colour differences.

 

Sound perception and balance are intimately associated senses in a fish. The organs of hearing are entirely internal, located within the skull, on each side of the brain and somewhat behind the eyes. Sound waves, especially those of low frequencies, travel readily through water and impinge directly upon the bones and fluids of the head and body, to be transmitted to the hearing organs. Fishes readily respond to sound; for example, a trout conditioned to escape by the approach of fishermen will take flight upon perceiving footsteps on a stream bank even if it cannot see a fisherman. Compared with humans, however, the range of sound frequencies heard by fishes is greatly restricted. Many fishes communicate with each other by producing sounds in their swim bladders, in their throats by rasping their teeth, and in other ways.

 

A fish or other vertebrate seldom has to rely on a single type of sensory information to determine the nature of the environment around it. A catfish uses taste and touch when examining a food object with its oral barbels. Like most other animals, fishes have many touch receptors over their body surface. Pain and temperature receptors also are present in fishes and presumably produce the same kind of information to a fish as to humans. Fishes react in a negative fashion to stimuli that would be painful to human beings, suggesting that they feel a sensation of pain.

 

An important sensory system in fishes that is absent in other vertebrates (except some amphibians) is the lateral line system. This consists of a series of heavily innervated small canals located in the skin and bone around the eyes, along the lower jaw, over the head, and down the mid-side of the body, where it is associated with the scales. Intermittently along these canals are located tiny sensory organs (pit organs) that apparently detect changes in pressure. The system allows a fish to sense changes in water currents and pressure, thereby helping the fish to orient itself to the various changes that occur in the physical environment.

  

Go to the Book with image in the Internet Archive

Title: United States Naval Medical Bulletin Vol. 15, Nos. 1-4, 1921

Creator: U.S. Navy. Bureau of Medicine and Surgery

Publisher:

Sponsor:

Contributor:

Date: 1921

Language: eng

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Table of Contents</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Number 1</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PORTRAIT OF SURGEON GENERAL E. R. STITT, U. S. NAVY —Frontispiece</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREFACE vii</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTICE TO SERVICE CONTRIBUTORS vii</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">THE NAVAL HOSPITAL, MARE ISLAND, CALIF. :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">HISTORY OF THE HOSPITAL.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Captain A. Farenholt, Medical Corps, U. S. N 1</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Operating room technique.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander Lucius W. Johnson, Medical Corps, and Bessie C.

Graham, Nurse Corps, U. S. N 10</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">The urological service.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander A. B. Hepler, Medical Corps, U. S. N__ 16</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">The roentgenological service.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant H. R. Coleman, Medical Corps, U. S. N 30</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">The laboratory.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant G. A. Gray, Medical Corps. U. S. N 34</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Features of organization.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander E. C. White, Medical Corps, U. S. N 40</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">General file and record system.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant D. C. Allen, Medical Corps, U. S. N 4T</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Suggested clinical chart.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander M. C. Baker, Medical Corps, U. S. N 49</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">The theater.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Chief Pharmacist T. C. Hart, Medical Corps, U. S. N 50</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Study of one hundred navy desertions.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant A H. Ehrenclou. Medical Corps, U. S. N., and</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Lieutenant W. H. Wilson, Chaplain Corps, U. S. N. R. F 53</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Surgical failures.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander Lucius W. Johnson, Medical Corps,</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">U. S. N 69</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Circumcision.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander Lucius W. Johnson, Medical Corps, U. S. N 77</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A glue cast for fractures of long bones.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant H. R. Coleman, Medical Corps, U. S. N . 79</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Tuberculin in the early diagnosis of tuberculosis.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant G. A. Gray, Medical Corps, U. S. N 81</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Diphtheria at Mare Island, Calif., in 1920.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant G. A. Gray, Medical Corps, U. S. N 84</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Agglutination of human erythrocytes by sera.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant G. A. Gray, Medical Corps, U. S. N., and Pharmacist's

Mate E. C. Upp, U. S. N 8G</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A method of ringing the hanging drop, etc.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Hospital Apprentice First Class D. G. Willard, U. S. N 92</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Preparation of colloidal gold solution.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Marie Karlen. Reserve Nurse Corps, and Pharmacist's Mate First Class

A. E. Bourke, U. S. N 94</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Report of seventy-five refraction cases.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant W. D. Horner, Medical Corps, U. S. N 95</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Empyema cases.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant E. R. Guinan, Medical Corps, U. S. N 99</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Acute mastoiditis. Page.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant C. N. Meador, Medical Corps, U. S. N 106</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Dental foci in the etiology of systemic disease.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant A. H. Ehrenclou, Medical Corps, and Lieutenant</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">B. F. Loveall, Dental Corps, U. S. N 109</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Transfusion in medical cases.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant D. H. Murray, Medical Corps, TJ. S. N 117</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A DENTAL BRANCH OF THE HOSPITAL COBPS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant B. F. Loveall, Dental Corps, U. S. N 118</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A CASE OF TUBERCULOUS PEBICABDITI8.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant A. H. Ehrenclou, Medical Corps, U. S. N 120</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A CASE OF ACUTE ANILINE POISONING.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant A. H. Ehrenclou, Medical Corps, U. S. N 123</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A CASE OF TUBERCULOUS MENINGITIS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant J. J. Sale, Medical Corps, U. S. N 126</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A CASE OF NEUROPARALYTIC KERATITIS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant C. N. Meador, Medical Corps, U. S. N 127</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Vernal conjunctivitis treated with radium.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant W. D. Horner, Medical Corps, U. S. N 1 128</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A case of acute myelitis.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant L. E. Smith, Medical Corps, U. S. N 130</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A case of osteoma of the tibia.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant F. G. Linde, Medical Corps, U. S. N 131</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A DISLOCATED SEMILUNAR CARTHAGE.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant F. G. Linde, Medical Corps, U. S. N 132</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A CASE OF COMPOUND FRACTURE OF TIBIA AND FIBULA.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant F. G. Linde, Medical Corps, U. S. N 132</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A DEATH FROM NITRIC ACID POISONING.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant G. A. Gray, Medical Corps, U.S. N 133</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NECROSIS OF THE MANDIBLE ; TWO CASES.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant B. F. Loveall, Dental Corps, U. S. N 134</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">HISTORICAL.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Alexis Soyer.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Captain J. S. Taylor, Medical Corps, U. S. N 139</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">EDITORIAL.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Morale 175</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SPECIAL ARTICLES.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Venereal statistics of the Army and Navy: A study of certain published

reports.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Captain C. E. RIggs. Medical Corps, U. S. N 179</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Report of one hundred compound fractures due to shell fragments or

machine-gun bullets.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander A. L. Clifton, Medical Corps, U. S. N__ 191</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A Death From Novarsenobenzol.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander R. A. Torrance, Medical Corps, U. S. N 193</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Mercurochrome —220, in dentistry.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander W. L. Darnall, Dental Corps, U. S. N_ 194</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PROGRESS IN MEDICAL SCIENCES.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">General medicine. —Diagnosis and treatment of pulmonary tuberculosis.

—The clinical recognition of syphilis. —Mercury bichloride Intravenously. —

Transduodenal lavage. — Immunization against diphtheria. —Buccal auscultation

197</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Mental and nervous diseases. — Malingering. —Extending the field of

conscious control. —The patient himself. —Anxiety and fear 210</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Surgery. —Blood transfusion. —Dangers of transfusion. —Mixture of ethyl

chloride, chloroform, and ether for anesthesia. — Skin grafting.—Autoplasties

for baldness. —Bladder tumors 217</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Hygiene and sanitation. —Hospital tires.—Coffee and vitamines 223

Tropical medicine. —Sterilization of ova in bilharziasis.—Antimony in the

treatment of bilharziasis 226</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Eye, ear, nose, and throat. —Cause and diagnosis of glaucoma ; treatment

by myotics.— Corneal disease of tubercular origin. —Action of chloral on the

pupil 227</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTES AND COMMENTS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Enlistments. —Professional training of experienced officers.—The case of

the U. S. S. Pittsburgh. —Prostatic lithiasis.—Cessation of respiration 15

hours before death. —Chloropierin to exterminate rats. —The Annual Report of

the Surgeon General, U. S. Navy. —Finding malarial parasites.— Icterus in

malaria.—Excretion of quinine.— Student health at the University of

Iowa.—Conference on war victims. —Pleasure and profit in the Medical Corps of

the Navy. —Law regarding thermometers. —Adhesive plaster. —The essential in

nursing. —Laxative cookies.—Samoa. —The Navy Mutual Aid Association 236</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">BOOK NOTICES 251</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Number 2</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREFACE<span>   </span>VII</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTICE TO SERVICE CONTRIBUTORS VIII</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SPECIAL ARTICLES:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Treatment of influenza.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander J. L. Neilson, Medical Corps, U. S. N 269</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Intravenous use of magnesium sulphate in influenzal pneumonia.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant J. J. Hogan, Medical Corps, U. S. N. R.F.<span>  </span>277</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Accidental injuries from electric currents.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander W. J. Zalesky and Lieutenant W. T. Brown, Medical Corps,

U. S. N 279</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Methods of sterilization in dentistry.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander H. E. Harvey, Dental Corps, U. S. N. 282</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Peptic ulcer.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant C. S. Norburn, Medical Corps, U. S. N 285</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SURVEY OF FIFTY COURT-MARTIAL PRISONERS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant C. H. Castle, Medical Corps, U. S. N. R.F<span>  </span>291</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Hospital training of apprentices.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant A. H. Ehrenclou, Medical Corps, U. S. N 296</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Methods of instructing hospital corpsmen.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander W. M. Kerr. Medical Corps, U. S.N<span>  </span>302</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Standardizing treatment for venereal disease.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander W. D. Owens, Medical Corps, U. S. N 308</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Plan of organization for a naval hospital.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Captain R. P. Crandall and Commander W. A. Angwin, Medical Corps, U.

S. N 316</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">HISTORICAL:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SURGERY IN THE MIDDLE AGES.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Captain J. S. Taylor, Medical Corps, U. S.N<span>  </span>347</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">EDITORIAL:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Calling a spade an implement of horticultural utility 377</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">"To bide the hobbyhorse with the boys " 378</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SIGGESTED DEVICES:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">RETINOSCOPIC LENS HOLDER.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Captain J. S. Taylor, Medical Corps, U. S. N 383</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Strong room for alcohol and narcotics.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Captain A. Farenholt, Medical Corps, U. S. N 385</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Detection of mosquito larvae.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander J. C. Parham, Medical Corps, U. S. N 380</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">CLINICAL NOTES:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Tuberculous meningitis simulating lethargic encephalitis.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander W. A. Bloedorn, Medical Corps, U. S. N 387</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Advancement of ocular muscles by the Fox technique.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander C. B. Camerer, Medical Corps. U.S. N<span>   </span><span> </span>392</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Surgical treatment of "saddle nose" deformity.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander C. B. Camerer, Medical Corps. U. S. N 397</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A HAND PLASTIC.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander Lucius W. Johnson. Medical Corps, U. S. N 399</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Dislocation of first cervical vertebra.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Captain G. T. Smith, Medical Corps, U. S. N 400</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Death from neo-arsphenamine.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander W. .T. Za leaky and Lieutenant J. B. Bellinger, Medical Corps,

U. S. N 401</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Thrombosis of the lateral sinus.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander E. E. Koebbe, Medical Corps, U. S. N_ 403</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Orchitis complicating tonsillitis.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenants J. D. Benjamin and T. C. Quirk, Medical Corps, U. S. N<span>  </span>408</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Operations for trauma of the urethra.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant W. L. Cowles, Medical Corps, U. S. N. R. P 407</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Sea sickness.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander C. E. Henry. Medical Corps, U. S. N. R. F 410</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Treatment of the " West Indian chancroid."</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander W. H. Michael, Medical Corps, U. S. N 412</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PROGRESS IN MEDICAL SCIENCES:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">General medicine. —The arsphenaniines in therapeutics. —Recital absorption

of glucose 415</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Mental and nervous diseases. —lethargic encephalitis. —Theory of hysteria.

—Mental deficiency 420</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Surgery. —Resuscitation in death under anesthesia. —Advances in anesthesia.

— Sloughing in local anesthesia. —Anesthesia in abdominal surgery. —

Suppurating wounds after abdominal section. —Saving suppurating Incisions.

—Abdominal adhesions. —Perforating gastric and duodenal ulcer. — Persistence of

pyloric and duodenal ulcers. — Diverticula of the duodenum.— Orthopedic

treatment of burns. —Postoperative bronchial irritation. —Care of surgical patients.

—End-to-end anastomosis. —Genital tuberculosis.— Radium therapy of cancer of

bladder. — Radium and malignant genitourinary disease.—Bone tumors. —Fracture

of vertebrae. —Penetrating wounds of chest. —Operation for empyema.—Plastic war

surgery in civil life. —The war's contribution to civil surgery 429</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Hygiene and sanitation. —Typhus fever in Serbia 455</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Pathology, bactkriology, and animal parasitology. —Diagnosis of cholera.

—Staining malarial parasites. —Saprophytysm of venereal organisms. — Variation

in size of red cells. —Anophellnes of California. —Reaction from echinococcus fluid

457</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Eye, ear, nose, and throat.— Encephalitis lethargica<span>  </span>487</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTES AND COMMENTS: <span> </span></p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Bronchospirochaetosis. — Starvation edema. —Dried cabbage as an antiscorbutic.

—Miner's nystagmus. —Endocrines and the teeth. — Orientation of bats. — Sugar

production.- -The teeth of the ancient Egyptians. —Treatment of enlarged

thymus. —Plague in Paris.— Antivenereal campaign in Rouen.— Medical school of

the University of Virginia. —Postgraduate study In the Japanese Navy. — National

Academy of Science.—Peking Unjon Medical College. — The dye Industry. — Naval

medical service as a career. —Naval dispensary and hospital defined.— Death of

Anton Weichselbaum. — Action of the Women's Civic League, Maiden, Mass. — Dr.

Russel H. Boggs. — Preservation of leather. —Service publications. —Picric acid

<span> </span>469</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">REPORTS :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Sewage system in Charlotte Amalia.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant R. L. Pettigrew, Civil Engineer Corps, U. S. N. and

Lieutenant E. Peterson. Medical Corps, U. S. N 481</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Application of the Schick reaction to 2,011 naval recruits.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant B. F. Norwood. Medical Corps, U. S. N 486</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Smallpox in Haiti.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander K. C. Melborn, Medical Corps, U. S. N 492</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Sanitary report on Libau, Latvia.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander A. C. Smith and Lieutenant R. P. Parsons,

Medical Corps, U. S. N 492</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Summer school, Hampton Roads, Va.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander K. E. Lowman, Medical Corps, U. S. N 495</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">INFORMATION WANTED 498</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">BOOK NOTICES 499</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Number 3</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTICE TO SERVICE CONTRIBUTORS VI</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">CLINICAL NOTES : Surgical service of the United States Naval Hospital,

New Orleans, La.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander W. J. Riddick and Lieutenant Commander E. A.

Stephens, Medical Corps, U. S.N.<span>    </span><span> </span>507</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A CASE OF HYSTERIA IN THE NAVAL SERVICE.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander W. A. Bloedorn, Medical Corps, U. S. N.<span>   </span>515</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A CASE OF HYSTERICAL CONTRACTURE.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant A. H. Ehrenclou, Medical Corps, U. S. N 521</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">X-RAY PROCEDURE AND TECHNIQUE.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander I. E. Jacobs, Medical Corps, and Chief

Pharmacist's Mate C. B. Worster, U. S. N 524</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Interpretation of abdominal rigidity.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander Lucius W. Johnson, Medical Corps, U. S. N<span>    </span><span> </span>529</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A CASE OF ECHINOCOCCUS CYST.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant C. S. Norburn, Medical Corps, U. S. N 530</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NONCORRODIBLE INSTRUMENTS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander G. C. Thomas, Medical Corps, U. S. N 532</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Aseptic technique for canal instruments.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander H. E. Harvey, Dental Corps, U. S. N 533</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Traumata due to falling.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander H. H. Lane, Medical Corps, U. S. N<span>  </span><span> </span>535</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Administration of neosalvarsan.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant J. B. Bostick, Medical Corps, U. S. N 536</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Diet deficiency in Vincent's angina.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant C. H. Morris, Dental Corps, U. S. N 540</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Vincent's infection of the -mouth.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant (j. g.) J. B. Goodall, Dental Corps, U. S. N. R. F <span> </span>542</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Penetrating wound of the pelvis.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant F. P. Gardner, Medical Corps, U. S. N 544</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Traumatic rupture of spleen —removal.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander F. H. Bowman, Medical Corps, U.S. N., and

Lieutenant Commander E. M. Foote, Medical Corps, U. S. N. R. F 545</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Operation for wrist drop.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant J. I. Yohannan, Medical Corps, U. S. N 547</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A PLASTIC OPERATION ON THE MUSCLES OF THE SHOULDER.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant R. W. Auerbach, Medical Corps, U. S. N 54S</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A SIMPLE OPERATION FOR TRICHIASIS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant H. S. Cragin, Medical Corps, U. S. N. R. F 551</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A CASE OF ADENO-CARCINOMA.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander M. Boland, Medical Corps, U. S. N— 552</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Chancroidal infections.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant W. F. Pearce, Medical Corps, U. S. N 554</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A CA8E OF INNOCENT SYPHILIS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant J. W. Jones, Medical Corps, U. S. N 556</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A CASE OF CARCINOMA OF THE TESTICLE.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant W. J. Corcoran, Medical Corps, U. S. N 557</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Removal of an unusually large tumor.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander E. L. Jones, Medical Corps, U. S. N 558</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">HISTORICAL:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A RETROSPECT OF NAVAL AND MILITARY MEDICINE.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Captain J. S. Taylor, Medical Corps, U. S. N 561</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">EDITORIAL :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Accidental poisoning — Contributing to the Bulletin —The omission of

the—The future of nursing — Comparative values 627</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PROGRESS IN MEDICAL SCIENCES :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">General medicine — Mechanism of hiccough — Gases In arterial blood—Treatment

of arsenic poisoning —Treatment of encephalitis letharglca —New test for

nephritis—Blood in pellagra and beri beri —Ocular symptoms in sinus

disease—Reaction from repeated transfusions —Eye symptoms in epidemic

encephalitis —Diagnosis and treatment of hemorrhoids —Cost of venereal

disease—Future of medicine in the United States 637</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Mental and nervous diseases —The criminal—Brain lesions of dementia

praecox —Follow-up studies on mental patients 652</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Surgery—Trauma of the abdomen— Rubber dam tampon —Diagnosis of gastric

or duodenal ulcers —Postoperative thrombophlebitis — Treatment of fractured

patella —Affections of the tibial tubercle— 655</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Hygiene and Sanitation —Sanitary features of merchant ships 659</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTES AND COMMENTS :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Errata —Centenary of von Helmholtz —Retirement of Filippo Rho, Surgeon

General, Italian Navy—A diagnostic point in tuberculosis —Curing hemorrhoids

—The X-ray and art— Industrial code of<span>  </span>New

York —Preservation of eyesight —Basal metabolism —American Society of Tropical

Medicine —Laboratory work in the Far East— Dentistry in South America

—Fireprooflng of fabrics—The exploration of Mount Everest — Physical

development in Japan — Hiccough and encephalitis lethargica —Use of fish as

food in France — Service items 665</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">REPORTS :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Rat-Proofing at the United States Navy Yard, Key West, Fla.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander P. E. Garrison, Medical Corps, U. S. N 673</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Report of the Fifth Congress of the International Society of Surgery,

Paris.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant S. B. Burk, Medical Corps, U. S. N. R. F. (Inactive) 681</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Smallpox in Port Au Prince, Haiti.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant C. J. Brown, Medical Corps, U. S. N 695</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Medical Department of the United States Naval Torpedo Station,

Alexandria, Va.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander C. C. Kress, Medical Corps, U. S. N 701</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">The Herman-Perutz Reaction.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant G. V. Genzmer, Medical Corps, U. S. N. R. F 708</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">BOOK NOTICES 711</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Number 4</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREFACE V</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTICE TO SERVICE CONTRIBUTORS VI</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SPECIAL ARTICLES :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Color blindness.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Captain E. J. Grow, Medical Corps, U. S. N 717</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Cardiac irregularity.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander E. U. Reed, Medical Corps, U. S. N 732</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Handling of recruits, Marine Barracks, Parris Island.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander J. C. Parham, Medical Corps, U. S. N 740</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Four centuries in the treatment of syphilis.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant L. W. Shaffer, Medical Corps, U. S. N 749</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A Marine Corps field hospital.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander G. F. Cottle, Medical Corps, U. S. N<span>  </span><span> </span>762</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Training and care of the football squad, U. S. Naval Academy, Annapolis,

Md.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant M. H. Roberts, Medical Corps, U. S. N. R. F 770</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Gas poisoning in warfare.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant G. H. Mankin, Medical Corps, U. S. N 775</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Venereal prophylaxis among U. S. Marines at Honolulu.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander H. H. Lane, Medical Corps, U. S. N_. 783</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">HISTORICAL :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">The Manila Galleon.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander W. M. Kerr, Medical Corps, U. S. N. 787</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">EDITORIAL :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">On learning to write-—On several phases of syphilis 801</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SUGGESTED DEVICES :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Dental X-ray film holder.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander H. E. Harvey, Dental Corps. U. S. N_- 807</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Suggestion for recording dental conditions.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander H. E. Harvey, Dental Corps, U. S. N-- 807</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">CLINICAL NOTES :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A CASE OF CUTANEOUS SPOROTRICHOSIS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander R. E. Hoyt, Medical Corps, U. S. N 809</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Report of pellagra in Haiti.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander G. F. Clark, Medical Corps, U. S. N__ 813</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Acute rheumatic fever.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant W. M. Alberty, Medical Corps, U. S. N 814</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A case of poisoning by oil of chenopodium.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant B. F. Norwood, Medical Corps, U. S. N 818</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Brushing the teeth.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander H. E. Harvey, Dental Corps, U. S. N<span>  </span><span> </span>824</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">TWENTY-EIGHT CASES OF PNEUMONIA.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant J. R. Jeffrey, Medical Corps, U. S. N 825</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A CASE OF TUBERCULOUS MENINGITIS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander S. P. Taylor, Medical Corps, U. S. N— 830</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Cholecystectomy <span> </span>and pyelotomy in

Guam.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander A. H. Robnett, Medical Corps, U. S. N 831</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Elephantiasis of the scrotum.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant L. W. Breene, Medical Corps, U. S. N., and W. Zur Linden,

chief pharmacist, Medical Corps, U. S. N 884</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Rules for massage.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander W. S. Bainbridge, Medical Corps, U. S. N. R. F— 835</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PROGRESS IN MEDICAL SCIENCES :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">General medicine. —Transfusion of blood—Diabetes mellitus In the Negro

race— Diagnosis of syphilis In malarial subjects —So-called diseases of the

blood— Singultus— The role of the prostate and</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">seminal vesicles in arthritis —Medical aspects of naval aviation — Treating

syphilitics—The etiology of scurvy —Food accessory factors in relation to the

teeth 839</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Surgery. —Immediate surgery in fighting ships —Immediate surgery of war

wounds as practiced in hospital ships —The surgical treatment of empyema by a

closed method—Willems treatment of</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">knee-joint injuries —Observations on primary venereal sores—Resection

of the small intestine for war wounds —Tetanus in the British Army during the

European War 855</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Tropical medicine. —New method of treatment of trypanosomiasis — Differential

diagnosis in tropical fevers —Schistosomiasis in the Yangtse Valley—Carriers of

dysenteriae among soldiers —Liverpool School of Tropical Medicine 870</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Pathology, bacteriology, and animal parasitology. — Cultivation of gonococcus—Aestivo-autumnal

malaria Plasmodia —Virulence of diphtheria-like organisms 885</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Chemistry and pharmacy.—Absorption of calcium salts in man— Improvements

in the Nephelometer-Colorimeter — Substitution of turbidimetry for nephelometry

in certain biochemical methods of analysis— Creatinuria —Phosphoric acid in the

blood of normal infants—Basal metabolism of normal women—Fat-soluble vitamine— Standards

for normal basal metabolism 887</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Eye, ear, nose, and throat.- —Injuries to the ear in modern warfare— Injuries

to the ear in modern warfare— Symptomatology and diagnosis of foreign bodies in

the air and food passages—Etiology and prevention of injuries to the eye

—Mosher-Totl operation on the lachrymal sac —-Tuberculosis of the middle ear

892</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTES AND COMMENTS :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Colles's Fracture—The French view of an American medical congress —Case

Records of the Massachusetts General Hospital— National cancer week- —

Pharmacopoeia of China —Municipal disposal of garbage—American Journal of

Tropical Medicine —Danger of week-end camping in the Tropics — Influenza

epidemic in the British Navy —Benvenuto Cellini—A Consulting Surgeon in the

Near</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">East—Asphyxiation in Garages —Dental service In the British Navy

—Surgeon Captain Lomas, R. N.—Counsels and Ideals from the Writings of William

Osler —John Keats, apothecary and poet — Life and times of Ambroise

Pare—Treatment of ozena —Lead poisoning in the pottery trade—The International

Journal of Gastro-Enterology— Treatment of malarial fever —Formaldehyde

poisoning — Toxic effects of shaking arsphenamine solution —Peking Union Medical

College —Milk standards 901</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">BOOK NOTICES 921</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">INDEX 983</p>

 

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Title: United States Naval Medical Bulletin Vol. 15, Nos. 1-4, 1921

Creator: U.S. Navy. Bureau of Medicine and Surgery

Publisher:

Sponsor:

Contributor:

Date: 1921

Language: eng

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Table of Contents</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Number 1</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PORTRAIT OF SURGEON GENERAL E. R. STITT, U. S. NAVY —Frontispiece</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREFACE vii</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTICE TO SERVICE CONTRIBUTORS vii</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">THE NAVAL HOSPITAL, MARE ISLAND, CALIF. :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">HISTORY OF THE HOSPITAL.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Captain A. Farenholt, Medical Corps, U. S. N 1</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Operating room technique.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander Lucius W. Johnson, Medical Corps, and Bessie C.

Graham, Nurse Corps, U. S. N 10</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">The urological service.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander A. B. Hepler, Medical Corps, U. S. N__ 16</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">The roentgenological service.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant H. R. Coleman, Medical Corps, U. S. N 30</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">The laboratory.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant G. A. Gray, Medical Corps. U. S. N 34</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Features of organization.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander E. C. White, Medical Corps, U. S. N 40</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">General file and record system.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant D. C. Allen, Medical Corps, U. S. N 4T</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Suggested clinical chart.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander M. C. Baker, Medical Corps, U. S. N 49</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">The theater.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Chief Pharmacist T. C. Hart, Medical Corps, U. S. N 50</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Study of one hundred navy desertions.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant A H. Ehrenclou. Medical Corps, U. S. N., and</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Lieutenant W. H. Wilson, Chaplain Corps, U. S. N. R. F 53</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Surgical failures.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander Lucius W. Johnson, Medical Corps,</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">U. S. N 69</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Circumcision.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander Lucius W. Johnson, Medical Corps, U. S. N 77</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A glue cast for fractures of long bones.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant H. R. Coleman, Medical Corps, U. S. N . 79</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Tuberculin in the early diagnosis of tuberculosis.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant G. A. Gray, Medical Corps, U. S. N 81</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Diphtheria at Mare Island, Calif., in 1920.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant G. A. Gray, Medical Corps, U. S. N 84</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Agglutination of human erythrocytes by sera.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant G. A. Gray, Medical Corps, U. S. N., and Pharmacist's

Mate E. C. Upp, U. S. N 8G</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A method of ringing the hanging drop, etc.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Hospital Apprentice First Class D. G. Willard, U. S. N 92</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Preparation of colloidal gold solution.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Marie Karlen. Reserve Nurse Corps, and Pharmacist's Mate First Class

A. E. Bourke, U. S. N 94</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Report of seventy-five refraction cases.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant W. D. Horner, Medical Corps, U. S. N 95</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Empyema cases.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant E. R. Guinan, Medical Corps, U. S. N 99</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Acute mastoiditis. Page.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant C. N. Meador, Medical Corps, U. S. N 106</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Dental foci in the etiology of systemic disease.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant A. H. Ehrenclou, Medical Corps, and Lieutenant</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">B. F. Loveall, Dental Corps, U. S. N 109</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Transfusion in medical cases.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant D. H. Murray, Medical Corps, TJ. S. N 117</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A DENTAL BRANCH OF THE HOSPITAL COBPS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant B. F. Loveall, Dental Corps, U. S. N 118</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A CASE OF TUBERCULOUS PEBICABDITI8.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant A. H. Ehrenclou, Medical Corps, U. S. N 120</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A CASE OF ACUTE ANILINE POISONING.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant A. H. Ehrenclou, Medical Corps, U. S. N 123</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A CASE OF TUBERCULOUS MENINGITIS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant J. J. Sale, Medical Corps, U. S. N 126</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A CASE OF NEUROPARALYTIC KERATITIS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant C. N. Meador, Medical Corps, U. S. N 127</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Vernal conjunctivitis treated with radium.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant W. D. Horner, Medical Corps, U. S. N 1 128</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A case of acute myelitis.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant L. E. Smith, Medical Corps, U. S. N 130</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A case of osteoma of the tibia.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant F. G. Linde, Medical Corps, U. S. N 131</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A DISLOCATED SEMILUNAR CARTHAGE.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant F. G. Linde, Medical Corps, U. S. N 132</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A CASE OF COMPOUND FRACTURE OF TIBIA AND FIBULA.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant F. G. Linde, Medical Corps, U. S. N 132</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A DEATH FROM NITRIC ACID POISONING.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant G. A. Gray, Medical Corps, U.S. N 133</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NECROSIS OF THE MANDIBLE ; TWO CASES.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant B. F. Loveall, Dental Corps, U. S. N 134</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">HISTORICAL.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Alexis Soyer.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Captain J. S. Taylor, Medical Corps, U. S. N 139</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">EDITORIAL.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Morale 175</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SPECIAL ARTICLES.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Venereal statistics of the Army and Navy: A study of certain published

reports.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Captain C. E. RIggs. Medical Corps, U. S. N 179</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Report of one hundred compound fractures due to shell fragments or

machine-gun bullets.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander A. L. Clifton, Medical Corps, U. S. N__ 191</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A Death From Novarsenobenzol.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander R. A. Torrance, Medical Corps, U. S. N 193</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Mercurochrome —220, in dentistry.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander W. L. Darnall, Dental Corps, U. S. N_ 194</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PROGRESS IN MEDICAL SCIENCES.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">General medicine. —Diagnosis and treatment of pulmonary tuberculosis.

—The clinical recognition of syphilis. —Mercury bichloride Intravenously. —

Transduodenal lavage. — Immunization against diphtheria. —Buccal auscultation

197</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Mental and nervous diseases. — Malingering. —Extending the field of

conscious control. —The patient himself. —Anxiety and fear 210</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Surgery. —Blood transfusion. —Dangers of transfusion. —Mixture of ethyl

chloride, chloroform, and ether for anesthesia. — Skin grafting.—Autoplasties

for baldness. —Bladder tumors 217</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Hygiene and sanitation. —Hospital tires.—Coffee and vitamines 223

Tropical medicine. —Sterilization of ova in bilharziasis.—Antimony in the

treatment of bilharziasis 226</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Eye, ear, nose, and throat. —Cause and diagnosis of glaucoma ; treatment

by myotics.— Corneal disease of tubercular origin. —Action of chloral on the

pupil 227</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTES AND COMMENTS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Enlistments. —Professional training of experienced officers.—The case of

the U. S. S. Pittsburgh. —Prostatic lithiasis.—Cessation of respiration 15

hours before death. —Chloropierin to exterminate rats. —The Annual Report of

the Surgeon General, U. S. Navy. —Finding malarial parasites.— Icterus in

malaria.—Excretion of quinine.— Student health at the University of

Iowa.—Conference on war victims. —Pleasure and profit in the Medical Corps of

the Navy. —Law regarding thermometers. —Adhesive plaster. —The essential in

nursing. —Laxative cookies.—Samoa. —The Navy Mutual Aid Association 236</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">BOOK NOTICES 251</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Number 2</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREFACE<span>   </span>VII</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTICE TO SERVICE CONTRIBUTORS VIII</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SPECIAL ARTICLES:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Treatment of influenza.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander J. L. Neilson, Medical Corps, U. S. N 269</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Intravenous use of magnesium sulphate in influenzal pneumonia.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant J. J. Hogan, Medical Corps, U. S. N. R.F.<span>  </span>277</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Accidental injuries from electric currents.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander W. J. Zalesky and Lieutenant W. T. Brown, Medical Corps,

U. S. N 279</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Methods of sterilization in dentistry.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander H. E. Harvey, Dental Corps, U. S. N. 282</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Peptic ulcer.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant C. S. Norburn, Medical Corps, U. S. N 285</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SURVEY OF FIFTY COURT-MARTIAL PRISONERS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant C. H. Castle, Medical Corps, U. S. N. R.F<span>  </span>291</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Hospital training of apprentices.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant A. H. Ehrenclou, Medical Corps, U. S. N 296</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Methods of instructing hospital corpsmen.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander W. M. Kerr. Medical Corps, U. S.N<span>  </span>302</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Standardizing treatment for venereal disease.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander W. D. Owens, Medical Corps, U. S. N 308</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Plan of organization for a naval hospital.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Captain R. P. Crandall and Commander W. A. Angwin, Medical Corps, U.

S. N 316</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">HISTORICAL:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SURGERY IN THE MIDDLE AGES.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Captain J. S. Taylor, Medical Corps, U. S.N<span>  </span>347</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">EDITORIAL:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Calling a spade an implement of horticultural utility 377</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">"To bide the hobbyhorse with the boys " 378</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SIGGESTED DEVICES:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">RETINOSCOPIC LENS HOLDER.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Captain J. S. Taylor, Medical Corps, U. S. N 383</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Strong room for alcohol and narcotics.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Captain A. Farenholt, Medical Corps, U. S. N 385</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Detection of mosquito larvae.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander J. C. Parham, Medical Corps, U. S. N 380</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">CLINICAL NOTES:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Tuberculous meningitis simulating lethargic encephalitis.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander W. A. Bloedorn, Medical Corps, U. S. N 387</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Advancement of ocular muscles by the Fox technique.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander C. B. Camerer, Medical Corps. U.S. N<span>   </span><span> </span>392</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Surgical treatment of "saddle nose" deformity.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander C. B. Camerer, Medical Corps. U. S. N 397</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A HAND PLASTIC.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander Lucius W. Johnson. Medical Corps, U. S. N 399</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Dislocation of first cervical vertebra.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Captain G. T. Smith, Medical Corps, U. S. N 400</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Death from neo-arsphenamine.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander W. .T. Za leaky and Lieutenant J. B. Bellinger, Medical Corps,

U. S. N 401</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Thrombosis of the lateral sinus.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander E. E. Koebbe, Medical Corps, U. S. N_ 403</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Orchitis complicating tonsillitis.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenants J. D. Benjamin and T. C. Quirk, Medical Corps, U. S. N<span>  </span>408</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Operations for trauma of the urethra.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant W. L. Cowles, Medical Corps, U. S. N. R. P 407</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Sea sickness.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander C. E. Henry. Medical Corps, U. S. N. R. F 410</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Treatment of the " West Indian chancroid."</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander W. H. Michael, Medical Corps, U. S. N 412</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PROGRESS IN MEDICAL SCIENCES:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">General medicine. —The arsphenaniines in therapeutics. —Recital absorption

of glucose 415</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Mental and nervous diseases. —lethargic encephalitis. —Theory of hysteria.

—Mental deficiency 420</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Surgery. —Resuscitation in death under anesthesia. —Advances in anesthesia.

— Sloughing in local anesthesia. —Anesthesia in abdominal surgery. —

Suppurating wounds after abdominal section. —Saving suppurating Incisions.

—Abdominal adhesions. —Perforating gastric and duodenal ulcer. — Persistence of

pyloric and duodenal ulcers. — Diverticula of the duodenum.— Orthopedic

treatment of burns. —Postoperative bronchial irritation. —Care of surgical patients.

—End-to-end anastomosis. —Genital tuberculosis.— Radium therapy of cancer of

bladder. — Radium and malignant genitourinary disease.—Bone tumors. —Fracture

of vertebrae. —Penetrating wounds of chest. —Operation for empyema.—Plastic war

surgery in civil life. —The war's contribution to civil surgery 429</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Hygiene and sanitation. —Typhus fever in Serbia 455</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Pathology, bactkriology, and animal parasitology. —Diagnosis of cholera.

—Staining malarial parasites. —Saprophytysm of venereal organisms. — Variation

in size of red cells. —Anophellnes of California. —Reaction from echinococcus fluid

457</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Eye, ear, nose, and throat.— Encephalitis lethargica<span>  </span>487</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTES AND COMMENTS: <span> </span></p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Bronchospirochaetosis. — Starvation edema. —Dried cabbage as an antiscorbutic.

—Miner's nystagmus. —Endocrines and the teeth. — Orientation of bats. — Sugar

production.- -The teeth of the ancient Egyptians. —Treatment of enlarged

thymus. —Plague in Paris.— Antivenereal campaign in Rouen.— Medical school of

the University of Virginia. —Postgraduate study In the Japanese Navy. — National

Academy of Science.—Peking Unjon Medical College. — The dye Industry. — Naval

medical service as a career. —Naval dispensary and hospital defined.— Death of

Anton Weichselbaum. — Action of the Women's Civic League, Maiden, Mass. — Dr.

Russel H. Boggs. — Preservation of leather. —Service publications. —Picric acid

<span> </span>469</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">REPORTS :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Sewage system in Charlotte Amalia.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant R. L. Pettigrew, Civil Engineer Corps, U. S. N. and

Lieutenant E. Peterson. Medical Corps, U. S. N 481</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Application of the Schick reaction to 2,011 naval recruits.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant B. F. Norwood. Medical Corps, U. S. N 486</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Smallpox in Haiti.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander K. C. Melborn, Medical Corps, U. S. N 492</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Sanitary report on Libau, Latvia.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander A. C. Smith and Lieutenant R. P. Parsons,

Medical Corps, U. S. N 492</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Summer school, Hampton Roads, Va.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander K. E. Lowman, Medical Corps, U. S. N 495</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">INFORMATION WANTED 498</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">BOOK NOTICES 499</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Number 3</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTICE TO SERVICE CONTRIBUTORS VI</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">CLINICAL NOTES : Surgical service of the United States Naval Hospital,

New Orleans, La.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander W. J. Riddick and Lieutenant Commander E. A.

Stephens, Medical Corps, U. S.N.<span>    </span><span> </span>507</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A CASE OF HYSTERIA IN THE NAVAL SERVICE.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander W. A. Bloedorn, Medical Corps, U. S. N.<span>   </span>515</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A CASE OF HYSTERICAL CONTRACTURE.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant A. H. Ehrenclou, Medical Corps, U. S. N 521</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">X-RAY PROCEDURE AND TECHNIQUE.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander I. E. Jacobs, Medical Corps, and Chief

Pharmacist's Mate C. B. Worster, U. S. N 524</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Interpretation of abdominal rigidity.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander Lucius W. Johnson, Medical Corps, U. S. N<span>    </span><span> </span>529</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A CASE OF ECHINOCOCCUS CYST.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant C. S. Norburn, Medical Corps, U. S. N 530</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NONCORRODIBLE INSTRUMENTS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander G. C. Thomas, Medical Corps, U. S. N 532</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Aseptic technique for canal instruments.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander H. E. Harvey, Dental Corps, U. S. N 533</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Traumata due to falling.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander H. H. Lane, Medical Corps, U. S. N<span>  </span><span> </span>535</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Administration of neosalvarsan.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant J. B. Bostick, Medical Corps, U. S. N 536</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Diet deficiency in Vincent's angina.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant C. H. Morris, Dental Corps, U. S. N 540</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Vincent's infection of the -mouth.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant (j. g.) J. B. Goodall, Dental Corps, U. S. N. R. F <span> </span>542</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Penetrating wound of the pelvis.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant F. P. Gardner, Medical Corps, U. S. N 544</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Traumatic rupture of spleen —removal.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander F. H. Bowman, Medical Corps, U.S. N., and

Lieutenant Commander E. M. Foote, Medical Corps, U. S. N. R. F 545</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Operation for wrist drop.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant J. I. Yohannan, Medical Corps, U. S. N 547</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A PLASTIC OPERATION ON THE MUSCLES OF THE SHOULDER.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant R. W. Auerbach, Medical Corps, U. S. N 54S</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A SIMPLE OPERATION FOR TRICHIASIS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant H. S. Cragin, Medical Corps, U. S. N. R. F 551</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A CASE OF ADENO-CARCINOMA.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander M. Boland, Medical Corps, U. S. N— 552</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Chancroidal infections.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant W. F. Pearce, Medical Corps, U. S. N 554</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A CA8E OF INNOCENT SYPHILIS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant J. W. Jones, Medical Corps, U. S. N 556</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A CASE OF CARCINOMA OF THE TESTICLE.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant W. J. Corcoran, Medical Corps, U. S. N 557</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Removal of an unusually large tumor.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander E. L. Jones, Medical Corps, U. S. N 558</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">HISTORICAL:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A RETROSPECT OF NAVAL AND MILITARY MEDICINE.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Captain J. S. Taylor, Medical Corps, U. S. N 561</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">EDITORIAL :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Accidental poisoning — Contributing to the Bulletin —The omission of

the—The future of nursing — Comparative values 627</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PROGRESS IN MEDICAL SCIENCES :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">General medicine — Mechanism of hiccough — Gases In arterial blood—Treatment

of arsenic poisoning —Treatment of encephalitis letharglca —New test for

nephritis—Blood in pellagra and beri beri —Ocular symptoms in sinus

disease—Reaction from repeated transfusions —Eye symptoms in epidemic

encephalitis —Diagnosis and treatment of hemorrhoids —Cost of venereal

disease—Future of medicine in the United States 637</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Mental and nervous diseases —The criminal—Brain lesions of dementia

praecox —Follow-up studies on mental patients 652</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Surgery—Trauma of the abdomen— Rubber dam tampon —Diagnosis of gastric

or duodenal ulcers —Postoperative thrombophlebitis — Treatment of fractured

patella —Affections of the tibial tubercle— 655</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Hygiene and Sanitation —Sanitary features of merchant ships 659</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTES AND COMMENTS :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Errata —Centenary of von Helmholtz —Retirement of Filippo Rho, Surgeon

General, Italian Navy—A diagnostic point in tuberculosis —Curing hemorrhoids

—The X-ray and art— Industrial code of<span>  </span>New

York —Preservation of eyesight —Basal metabolism —American Society of Tropical

Medicine —Laboratory work in the Far East— Dentistry in South America

—Fireprooflng of fabrics—The exploration of Mount Everest — Physical

development in Japan — Hiccough and encephalitis lethargica —Use of fish as

food in France — Service items 665</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">REPORTS :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Rat-Proofing at the United States Navy Yard, Key West, Fla.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander P. E. Garrison, Medical Corps, U. S. N 673</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Report of the Fifth Congress of the International Society of Surgery,

Paris.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant S. B. Burk, Medical Corps, U. S. N. R. F. (Inactive) 681</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Smallpox in Port Au Prince, Haiti.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant C. J. Brown, Medical Corps, U. S. N 695</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Medical Department of the United States Naval Torpedo Station,

Alexandria, Va.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander C. C. Kress, Medical Corps, U. S. N 701</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">The Herman-Perutz Reaction.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant G. V. Genzmer, Medical Corps, U. S. N. R. F 708</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">BOOK NOTICES 711</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Number 4</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREFACE V</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTICE TO SERVICE CONTRIBUTORS VI</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SPECIAL ARTICLES :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Color blindness.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Captain E. J. Grow, Medical Corps, U. S. N 717</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Cardiac irregularity.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander E. U. Reed, Medical Corps, U. S. N 732</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Handling of recruits, Marine Barracks, Parris Island.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander J. C. Parham, Medical Corps, U. S. N 740</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Four centuries in the treatment of syphilis.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant L. W. Shaffer, Medical Corps, U. S. N 749</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A Marine Corps field hospital.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander G. F. Cottle, Medical Corps, U. S. N<span>  </span><span> </span>762</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Training and care of the football squad, U. S. Naval Academy, Annapolis,

Md.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant M. H. Roberts, Medical Corps, U. S. N. R. F 770</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Gas poisoning in warfare.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant G. H. Mankin, Medical Corps, U. S. N 775</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Venereal prophylaxis among U. S. Marines at Honolulu.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander H. H. Lane, Medical Corps, U. S. N_. 783</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">HISTORICAL :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">The Manila Galleon.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander W. M. Kerr, Medical Corps, U. S. N. 787</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">EDITORIAL :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">On learning to write-—On several phases of syphilis 801</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SUGGESTED DEVICES :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Dental X-ray film holder.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander H. E. Harvey, Dental Corps. U. S. N_- 807</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Suggestion for recording dental conditions.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander H. E. Harvey, Dental Corps, U. S. N-- 807</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">CLINICAL NOTES :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A CASE OF CUTANEOUS SPOROTRICHOSIS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander R. E. Hoyt, Medical Corps, U. S. N 809</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Report of pellagra in Haiti.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander G. F. Clark, Medical Corps, U. S. N__ 813</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Acute rheumatic fever.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant W. M. Alberty, Medical Corps, U. S. N 814</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A case of poisoning by oil of chenopodium.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant B. F. Norwood, Medical Corps, U. S. N 818</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Brushing the teeth.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander H. E. Harvey, Dental Corps, U. S. N<span>  </span><span> </span>824</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">TWENTY-EIGHT CASES OF PNEUMONIA.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant J. R. Jeffrey, Medical Corps, U. S. N 825</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A CASE OF TUBERCULOUS MENINGITIS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander S. P. Taylor, Medical Corps, U. S. N— 830</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Cholecystectomy <span> </span>and pyelotomy in

Guam.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander A. H. Robnett, Medical Corps, U. S. N 831</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Elephantiasis of the scrotum.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant L. W. Breene, Medical Corps, U. S. N., and W. Zur Linden,

chief pharmacist, Medical Corps, U. S. N 884</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Rules for massage.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander W. S. Bainbridge, Medical Corps, U. S. N. R. F— 835</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PROGRESS IN MEDICAL SCIENCES :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">General medicine. —Transfusion of blood—Diabetes mellitus In the Negro

race— Diagnosis of syphilis In malarial subjects —So-called diseases of the

blood— Singultus— The role of the prostate and</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">seminal vesicles in arthritis —Medical aspects of naval aviation — Treating

syphilitics—The etiology of scurvy —Food accessory factors in relation to the

teeth 839</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Surgery. —Immediate surgery in fighting ships —Immediate surgery of war

wounds as practiced in hospital ships —The surgical treatment of empyema by a

closed method—Willems treatment of</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">knee-joint injuries —Observations on primary venereal sores—Resection

of the small intestine for war wounds —Tetanus in the British Army during the

European War 855</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Tropical medicine. —New method of treatment of trypanosomiasis — Differential

diagnosis in tropical fevers —Schistosomiasis in the Yangtse Valley—Carriers of

dysenteriae among soldiers —Liverpool School of Tropical Medicine 870</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Pathology, bacteriology, and animal parasitology. — Cultivation of gonococcus—Aestivo-autumnal

malaria Plasmodia —Virulence of diphtheria-like organisms 885</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Chemistry and pharmacy.—Absorption of calcium salts in man— Improvements

in the Nephelometer-Colorimeter — Substitution of turbidimetry for nephelometry

in certain biochemical methods of analysis— Creatinuria —Phosphoric acid in the

blood of normal infants—Basal metabolism of normal women—Fat-soluble vitamine— Standards

for normal basal metabolism 887</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Eye, ear, nose, and throat.- —Injuries to the ear in modern warfare— Injuries

to the ear in modern warfare— Symptomatology and diagnosis of foreign bodies in

the air and food passages—Etiology and prevention of injuries to the eye

—Mosher-Totl operation on the lachrymal sac —-Tuberculosis of the middle ear

892</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTES AND COMMENTS :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Colles's Fracture—The French view of an American medical congress —Case

Records of the Massachusetts General Hospital— National cancer week- —

Pharmacopoeia of China —Municipal disposal of garbage—American Journal of

Tropical Medicine —Danger of week-end camping in the Tropics — Influenza

epidemic in the British Navy —Benvenuto Cellini—A Consulting Surgeon in the

Near</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">East—Asphyxiation in Garages —Dental service In the British Navy

—Surgeon Captain Lomas, R. N.—Counsels and Ideals from the Writings of William

Osler —John Keats, apothecary and poet — Life and times of Ambroise

Pare—Treatment of ozena —Lead poisoning in the pottery trade—The International

Journal of Gastro-Enterology— Treatment of malarial fever —Formaldehyde

poisoning — Toxic effects of shaking arsphenamine solution —Peking Union Medical

College —Milk standards 901</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">BOOK NOTICES 921</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">INDEX 983</p>

 

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Hippopotamuses love water, which is why the Greeks named them the "river horse." Hippos spend up to 16 hours a day submerged in rivers and lakes to keep their massive bodies cool under the hot African sun. Hippos are graceful in water, good swimmers, and can hold their breath underwater for up to five minutes. However, they are often large enough to simply walk or stand on the lake floor, or lie in the shallows. Their eyes and nostrils are located high on their heads, which allows them to see and breathe while mostly submerged. Hippos also bask on the shoreline and secrete an oily red substance, which gave rise to the myth that they sweat blood. The liquid is actually a skin moistener and sunblock that may also provide protection against germs. At sunset, hippopotamuses leave the water and travel overland to graze. They may travel 6 miles (10 kilometers) in a night, along single-file pathways, to consume some 80 pounds (35 kilograms) of grass. Considering their enormous size, a hippo's food intake is relatively low. If threatened on land hippos may run for the water—they can match a human's speed for short distances. Hippo calves weigh nearly 100 pounds (45 kilograms) at birth and can suckle on land or underwater by closing their ears and nostrils. Each female has only one calf every two years. Soon after birth, mother and young join schools that provide some protection against crocodiles, lions, and hyenas. Hippos once had a broader distribution but now live in eastern central and southern sub-Saharan Africa, where their populations are in decline. A partially submerged hippopotamus tries to keep cool in the hot African sun. The hippopotamus (Hippopotamus amphibius), or hippo, from the ancient Greek for "river horse" (ἱπποπόταμος), is a large, mostly herbivorous mammal in sub-Saharan Africa, and one of only two extant species in the family Hippopotamidae (the other is the Pygmy Hippopotamus.) After the elephant and rhinoceros, the hippopotamus is the third largest land mammal and the heaviest extant artiodactyl. Despite their physical resemblance to pigs and other terrestrial even-toed ungulates, their closest living relatives are cetaceans (whales, porpoises, etc.) from which they diverged about 55 million years ago. The common ancestor of whales and hippos split from other even-toed ungulates around 60 million years ago. The earliest known hippopotamus fossils, belonging to the genus Kenyapotamus in Africa, date to around 16 million years ago.

The hippopotamus is semi-aquatic, inhabiting rivers, lakes and mangrove swamps, where territorial bulls preside over a stretch of river and groups of 5 to 30 females and young. During the day they remain cool by staying in the water or mud; reproduction and childbirth both occur in water. They emerge at dusk to graze on grass. While hippopotamuses rest near each other in the water, grazing is a solitary activity and hippos are not territorial on land. Hippos are recognizable by their barrel-shaped torso, enormous mouth and teeth, nearly hairless body, stubby legs and tremendous size. It is the third largest land mammal by weight (between 1½ and 3 tonnes), behind the white rhinoceros (1½ to 3½ tonnes) and the three species of elephant (3 to 9 tonnes). The hippopotamus is one of the largest quadrupeds and despite its stocky shape and short legs, it can easily outrun a human. Hippos have been clocked at 30 km/h (19 mph) over short distances. The hippopotamus is one of the most aggressive creatures in the world and is often regarded as one of the most dangerous animals in Africa. They are still threatened by habitat loss and poaching for their meat and ivory canine teeth. There is also a colony of non-zoo hippos in Colombia introduced by Pablo Escobar. The most recent theory of the origins of Hippopotamidae suggests that hippos and whales shared a common semi-aquatic ancestor that branched off from other artiodactyls around 60 million years ago.[13][15] This hypothesized ancestral group likely split into two branches around 54 million years ago.[12] One branch would evolve into cetaceans, possibly beginning about 52 million years ago with the proto-whale Pakicetus and other early whale ancestors collectively known as Archaeoceti, which eventually underwent aquatic adaptation into the completely aquatic cetaceans.[17] The other branch became the anthracotheres, a large family of four-legged beasts, the earliest of whom in the late Eocene would have resembled skinny hippopotamuses with comparatively small and narrow heads. All branches of the anthracotheres, except that which evolved into Hippopotamidae, became extinct during the Pliocene without leaving any descendants.[15]

A rough evolutionary lineage can be traced from Eocene and Oligocene species: Anthracotherium and Elomeryx to the Miocene Merycopotamus and Libycosaurus and the very latest anthracotheres in the Pliocene.[18] Merycopotamus, Libycosaurus and all hippopotamids can be considered to form a clade, with Libycosaurus being more closely related to hippos. Their common ancestor would have lived in the Miocene, about 20 million years ago. Hippopotamids are therefore deeply nested within the family Anthracotheriidae. The Hippopotamidae are believed to have evolved in Africa; the oldest known hippopotamid is the genus Kenyapotamus which lived in Africa from 16 to 8 million years ago. While hippopotamid species spread across Asia and Europe, no hippopotamuses have ever been discovered in the Americas, although various anthracothere genera emigrated into North America during the early Oligocene. From 7.5 to 1.8 million years ago an ancestor to the modern hippopotamus, Archaeopotamus, lived in Africa and the Middle East.[19]

While the fossil record of hippos is still poorly understood, the two modern genera, Hippopotamus and Choeropsis (sometimes Hexaprotodon), may have diverged as far back as 8 million years ago. Taxonomists disagree whether or not the modern Pygmy Hippopotamus is a member of Hexaprotodon —an apparently paraphyletic genus also embracing many extinct Asian hippopotamuses that is more closely related to Hippopotamus, or Choeropsis —an older and basal genus.[18][19]

[edit]Extinct species

Three species of Malagasy Hippopotamus became extinct during the Holocene on Madagascar, one of them within the past 1,000 years. The Malagasy Hippos were smaller than the modern hippopotamus, likely through the process of insular dwarfism.[20] There is fossil evidence that many Malagasy Hippos were hunted by humans, a likely factor in their eventual extinction.[20] Isolated members of Malagasy Hippopotamus may have survived in remote pockets; in 1976, villagers described a living animal called the Kilopilopitsofy, which may have been a Malagasy Hippopotamus.[21]

Two species of Hippopotamus, the European Hippopotamus (H. antiquus) and H. gorgops ranged throughout continental Europe and the British Isles. Both species became extinct before the last glaciation. Ancestors of European Hippos found their way to many islands of the Mediterranean during the Pleistocene.[22] Both species were larger than the modern hippopotamus, averaging about 1 meter (3.3 feet) longer. The Pleistocene also saw a number of dwarf species evolve on several Mediterranean islands including Crete (H. creutzburgi), Cyprus (H. minor), Malta (H. melitensis) and Sicily (H. pentlandi). Of these, the Cyprus Dwarf Hippopotamus, survived until the end of the Pleistocene or early Holocene. Evidence from an archaeological site Aetokremnos, continues to cause debate on whether or not the species was encountered, and was driven to extinction, by man. Hippopotamuses are among the largest living mammals; only elephants and some rhinoceroses and whales are heavier. They can live in the water or on land. Their specific gravity allows them to sink and walk or run along the bottom of a river. Hippos are considered megafauna, but unlike all other African megafauna, hippos have adapted for a semi-aquatic life in freshwater lakes and rivers.[9]:3 A hippo's lifespan is typically 40–50 years.[6]:277 Donna the Hippo, 60, was the oldest living hippo in captivity. She lived at the Mesker Park Zoo in Evansville, Indiana, USA[24][25] until her death on August 1, 2012. The oldest hippo ever recorded was called Tanga; she lived in Munich, Germany, and died in 1995 at the age of 61.[26]

Because of their enormous size, hippopotamuses are difficult to weigh in the wild. Most estimates of the weight come from culling operations that were carried out in the 1960s. The average weights for adult males ranged between 1,500–1,800 kg (3,300–4,000 lb). Females are smaller than their male counterparts, with average weights measuring between 1,300–1,500 kg (2,900–3,300 lb).[9]:12 Older males can get much larger, reaching at least 3,200 kg (7,100 lb) with a few exceptional specimens exceeding 3,600 kg (7,900 lb).[27][28] The heaviest known hippopotamus weighed approximately 4,500 kg (9,900 lb).[29] Male hippos appear to continue growing throughout their lives; females reach a maximum weight at around age 25.[30]

Hippos measure 3.3 to 5.2 meters (11 to 17 ft) long, including a tail of about 56 centimeters (22 in) in length and average about 1.5 meters (5 ft) tall at the shoulder.[31][32] The range of hippopotamus sizes overlaps with the range of the white rhinoceros; use of different metrics makes it unclear which is the largest land animal after elephants. Even though they are bulky animals, hippopotamuses can run faster than a human on land. Estimates of their running speed vary from 30 km/h (18 mph) to 40 km/h (25 mph), or even 50 km/h (30 mph). The hippo can maintain these higher speeds for only a few hundred meters. Despite being semi-aquatic and having webbed feet, an adult hippo is not a particularly good swimmer nor can it float. It is rarely found in deep water; when it is, the animal moves by porpoise-like leaps from the bottom. The eyes, ears, and nostrils of hippos are placed high on the roof of the skull. This allows them to be in the water with most of their body submerged in the waters and mud of tropical rivers to stay cool and prevent sunburn. Their skeletal structure is graviportal, adapted to carrying the animals' enormous weight. Hippopotamuses have small legs (relative to other megafauna) because the water in which they live reduces the weight burden. Unlike most other semi-aquatic animals, the hippopotamus has very little hair.[6]:260 The skin is 6 in (15 cm) thick,[33] providing it great protection against conspecifics and predators. The animals's upper parts are purplish-gray to blue-black while the under parts and areas around the eyes and ears can be brownish-pink.[6]:260 The testes of the males descend only partially and a scrotum is not present. In addition, the penis retracts into the body when not erect. The genitals of the female are unusual in that the vagina is ridged and two large diverticula protrude from the vulval vestibule. The function of these is unknown.[9]:28–29

The hippo's jaw is powered by a large masseter and a well developed digastric; the latter loops up behind the former to the hyoid.[6]:259 The jaw hinge is located far back enough to allow the animal to open its mouth at almost 180°.[9]:17 On the National Geographic Channel television program, "Dangerous Encounters with Brady Barr", Dr. Brady Barr measured the bite force of an adult female hippo at 8100 N (1821 lbf); Barr also attempted to measure the bite pressure of an adult male hippo, but had to abandon the attempt due to the male's aggressiveness.[34] Hippopotamus teeth sharpen themselves as they grind together. The lower canines and lower incisors are enlarged, especially in males, and grow continuously. The incisors can reach 40 cm (16 in) while the canines reach up to 50 cm (20 in).[33]

Their skin secretes a natural sunscreen substance which is red-colored. The secretion is sometimes referred to as "blood sweat," but is neither blood nor sweat. This secretion is initially colorless and turns red-orange within minutes, eventually becoming brown. Two distinct pigments have been identified in the secretions, one red (hipposudoric acid) and one orange (norhipposudoric acid). The two pigments are highly acidic compounds. Both pigments inhibit the growth of disease-causing bacteria; as well, the light absorption of both pigments peaks in the ultraviolet range, creating a sunscreen effect. All hippos, even those with different diets, secrete the pigments, so it does not appear that food is the source of the pigments. Instead, the animals may synthesize the pigments from precursors such as the amino acid tyrosine. Hippopotamus amphibius was widespread in North Africa and Europe during the Eemian[36] and late Pleistocene until about 30,000 years ago. The species was common in Egypt's Nile region during antiquity but has since been extirpated. Pliny the Elder writes that, in his time, the best location in Egypt for capturing this animal was in the Saite nome;[37] the animal could still be found along the Damietta branch after the Arab Conquest in 639. Hippos are still found in the rivers and lakes of the northern Democratic Republic of the Congo, Uganda, Tanzania and Kenya, north through to Ethiopia, Somalia and Sudan, west from Ghana to Gambia, and also in Southern Africa (Botswana, Republic of South Africa, Zimbabwe, Zambia, Mozambique). Genetic evidence suggests that common hippos in Africa experienced a marked population expansion during or after the Pleistocene Epoch, attributed to an increase in water bodies at the end of the era. These findings have important conservation implications as hippo populations across the continent are currently threatened by loss of access to fresh water.[10] Hippos are also subject to unregulated hunting and poaching. In May 2006 the hippopotamus was identified as a vulnerable species on the IUCN Red List drawn up by the World Conservation Union (IUCN), with an estimated population of between 125,000 and 150,000 hippos, a decline of between 7% and 20% since the IUCN's 1996 study. Zambia (40,000) and Tanzania (20,000–30,000) possess the largest populations.[1]

The hippo population declined most dramatically in the Democratic Republic of the Congo.[38] The population in Virunga National Park had dropped to 800 or 900 from around 29,000 in the mid 1970s.[39] The decline is attributed to the disruptions caused by the Second Congo War.[39] The poachers are believed to be former Hutu rebels, poorly paid Congolese soldiers, and local militia groups.[39] Reasons for poaching include the belief that hippos are harmful to society, and also for money.[40] The sale of hippo meat is illegal, but black-market sales are difficult for Virunga National Park officers to track. Invasive potential

In the late 1980s, Pablo Escobar kept four hippos in a private menagerie at his residence in Hacienda Napoles, 100 km east of Medellín, Colombia, after buying them in New Orleans. They were deemed too difficult to seize and move after Escobar's fall, and hence left on the untended estate. By 2007, the animals had multiplied to 16 and had taken to roaming the area for food in the nearby Magdalena River.[41] In 2009, two adults and one calf escaped the herd, and after attacking humans and killing cattle, one of the adults (called "Pepe") was killed by hunters under authorization of the local authorities.[42][43] It is unknown what kind of effects the presence of hippos might have on the ecosystem in Colombia. According to experts interviewed by W Radio Colombia, the animals could survive in the Colombian jungles. It is believed that the lack of control from the Colombian government, which is not used to dealing with this species, could result in human fatalities. Hippos spend most of their days wallowing in the water or the mud, with the other members of their pod. The water serves to keep their body temperature down, and to keep their skin from drying out. With the exception of eating, most of hippopotamuses' lives —from childbirth, fighting with other hippos, to reproduction— occur in the water. Hippos leave the water at dusk and travel inland, sometimes up to 8 kilometers (5 mi), to graze on short grass, their main source of food. They spend four to five hours grazing and can consume 68 kilograms (150 lb) of grass each night.[44] Like almost any herbivore, they will consume many other plants if presented with them, but their diet in nature consists almost entirely of grass, with only minimal consumption of aquatic plants.[45] Hippos have (rarely) been filmed eating carrion, usually close to the water. There are other reports of meat-eating, and even cannibalism and predation.[46] The stomach anatomy of a hippo is not suited to carnivory, and meat-eating is likely caused by aberrant behavior or nutritional stress.[9]:84

The diet of hippos consists mostly of terrestrial grasses, even though they spend most of their time in the water. Most of their defecation occurs in the water, creating allochthonous deposits of organic matter along the river beds. These deposits have an unclear ecological function.[45] Because of their size and their habit of taking the same paths to feed, hippos can have a significant impact on the land they walk across, both by keeping the land clear of vegetation and depressing the ground. Over prolonged periods hippos can divert the paths of swamps and channels.[47]

Adult hippos move at speeds up to 8 km/h (5 mph) in water. Adult hippos typically resurface to breathe every three to five minutes. The young have to breathe every two to three minutes.[9]:4 The process of surfacing and breathing is automatic, and even a hippo sleeping underwater will rise and breathe without waking. A hippo closes its nostrils when it submerges into the water. As with fish and turtles on a coral reef, hippo occasionally visit cleaning stations and signal by wide-open mouth their readiness for being cleaned of parasites by certain species of fish. This situation is an example of mutualism in which the hippo benefits from the cleansing while the fish receive food.[ Studying the interaction of male and female hippopotamuses has long been complicated by the fact that hippos are not sexually dimorphic and thus females and young males are almost indistinguishable in the field.[49] Although hippos like to lie close to each other, they do not seem to form social bonds except between mothers and daughters, and are not social animals. The reason they huddle close together is unknown.[9]:49

Hippopotamuses are territorial only in water, where a bull presides over a small stretch of river, on average 250 meters in length, and containing ten females. The largest pods can contain over 100 hippos.[9]:50 Other bachelors are allowed in a bull's stretch, as long as they behave submissively toward the bull. The territories of hippos exist to establish mating rights. Within the pods, the hippos tend to segregate by gender. Bachelors will lounge near other bachelors, females with other females, and the bull on his own. When hippos emerge from the water to graze, they do so individually.[9]:4

Hippopotamuses appear to communicate verbally, through grunts and bellows, and it is thought that they may practice echolocation, but the purpose of these vocalizations is currently unknown. Hippos have the unique ability to hold their head partially above the water and send out a cry that travels through both water and air; hippos above and under water will respond.[ Female hippos reach sexual maturity at five to six years of age and have a gestation period of 8 months. A study of endocrine systems revealed that female hippopotamuses may begin puberty as early as 3 or 4 years of age.[51] Males reach maturity at around 7.5 years. A study of hippopotamus reproductive behavior in Uganda showed that peak conceptions occurred during the end of the wet season in the summer, and peak births occurred toward the beginning of the wet season in late winter. This is because of the female's estrous cycle; as with most large mammals, male hippopotamus spermatozoa is active year round. Studies of hippos in Zambia and South Africa also showed evidence of births occurring at the start of the wet season.[9]:60–61 After becoming pregnant, a female hippopotamus will typically not begin ovulation again for 17 months.[51]

Mating occurs in the water with the female submerged for most of the encounter,[9]:63 her head emerging periodically to draw breath. Baby hippos are born underwater at a weight between 25 and 45 kg (60–110 lb) and an average length of around 127 cm (50 in) and must swim to the surface to take their first breath. A mother typically gives birth to only one hippo, although twins also occur. The young often rest on their mothers' backs when in water that is too deep for them, and they swim underwater to suckle. They also will suckle on land when the mother leaves the water. Weaning starts between six and eight months after birth and most calves are fully weaned after a year.[9]:64 Like many other large mammals, hippos are described as K-strategists, in this case typically producing just one large, well-developed infant every couple of years (rather than large numbers of small, poorly developed young several times per year as is common among small mammals such as rodents. Hippopotamuses are by nature very aggressive animals, especially when young calves are present. Frequent targets of their aggression include crocodiles, which often inhabit the same river habitat as hippos. Nile crocodiles, lions and spotted hyenas are known to prey on young hippos.[53] Hippos are very aggressive towards humans, whom they commonly attack whether in boats or on land with no apparent provocation.[54] They are widely considered to be one of the most dangerous large animals in Africa.[55][56]

To mark territory, hippos spin their tails while defecating to distribute their excrement over a greater area.[57] Likely for the same reason, hippos are retromingent – that is, they urinate backwards.[58] When in combat, male hippos use their incisors to block each others attacks, and their lower canines to inflict damage.[6]:260 Hippos rarely kill each other, even in territorial challenges. Usually a territorial bull and a challenging bachelor will stop fighting when it is clear that one hippo is stronger. When hippos become overpopulated, or when a habitat starts to shrink, bulls will sometimes attempt to kill infants, but this behavior is not common under normal conditions.[52] Some incidents of hippo cannibalism have been documented, but it is believed to be the behavior of distressed or sick hippos, and not healthy behavior. The earliest evidence of human interaction with hippos comes from butchery cut marks upon hippo bones at Bouri Formation dated around 160,000 years ago.[59] Later rock paintings and engravings showing hippos being hunted have been found in the mountains of the central Sahara dated 4,000–5,000 years ago near Djanet in the Tassili n'Ajjer Mountains.[9]:1 The ancient Egyptians recognized the hippo as a ferocious denizen of the Nile.

The hippopotamus was also known to the Greeks and Romans. The Greek historian Herodotus described the hippopotamus in The Histories (written circa 440 BC) and the Roman Historian Pliny the Elder wrote about the hippopotamus in his encyclopedia Naturalis Historia (written circa 77 AD).[37][60] Hippopotamus was one of the many exotic animals brought to fight gladiators in Rome by the emperor Philip I the Arab to commemorate Rome's 1000 years anniversary in 248 AD. Silver coins with hippo's image were minted that year.[citation needed]

Zulu warriors preferred to be as brave as a hippopotamus, since even lions were not considered as brave. "In 1888, Captain Baden-Powell was part of a column searching for the Zulu chief Dinizulu, who was leading the Usutu people in revolt against the British colonists. The column was joined by John Dunn, a white Zulu chief, who led an impi (army) of 2000 Zulu warriors to join the British." [61]

The words of the Zulu anthem sounded like this:

"Een-gonyama Gonyama! "Invooboo! Yah-bo! Yah-bo! Invooboo!"

"John Dunn was at the head of his impi. [Baden Powell] asked him to translate the Zulu anthem his men had been singing. Dunn laughed and replied: "He is a lion. Yes, he is better than a lion—he is a hippopotamus. Hippopotamuses have long been popular zoo animals. The first zoo hippo in modern history was Obaysch who arrived at the London Zoo on May 25, 1850, where he attracted up to 10,000 visitors a day and inspired a popular song, the Hippopotamus Polka.[63] Hippos have remained popular zoo animals since Obaysch, and generally breed well in captivity. Their birth rates are lower than in the wild, but this is attributed to zoos' not wanting to breed as many hippos as possible, since hippos are large and relatively expensive animals to maintain.[9]:129[63]

Like many zoo animals, hippos were traditionally displayed in concrete exhibits. In the case of hippos, they usually had a pool of water and patch of grass. In the 1980s, zoo designers increasingly designed exhibits that reflected the animals' native habitats. The best known of these, the Toledo Zoo Hippoquarium, features a 360,000 gallon pool for hippos.[64] In 1987, researchers were able to tape, for the first time, an underwater birth (as in the wild) at the Toledo Zoo. The exhibit was so popular that the hippos became the logo of the Toledo Zoo. A red hippo represented the Ancient Egyptian god Set; the thigh is the 'phallic leg of set' symbolic of virility. Set's consort Tawaret was also seen as part hippo.[66] The hippopotamus-headed Tawaret was a goddess of protection in pregnancy and childbirth, because ancient Egyptians recognized the protective nature of a female hippopotamus toward her young.[67] The Ijo people wore masks of aquatic animals like the hippo when practicing their water spirit cults.[68] The Behemoth from the Book of Job, 40:15–24 is also thought to be based on a hippo.[69]

Hippos have been the subjects of various African folktales. According to a Bushmen story; when the Creator assigned each animal their place in nature, the hippos wanted to live in the water, but were refused out of fear that they might eat all the fish. After begging and pleading, the hippos were finally allowed to live in the water on the conditions that they would eat grass instead of fish and would fling their dung so that it can be inspected for fish bones.[70] In a Ndebele tale, the hippo originally had long, beautiful hair but was set on fire by a jealous hare and had to jump into a nearby pool. The hippo lost most of his hair and was too embarrassed to leave the water.[70]

Ever since Obaysch inspired the Hippopotamus Polka, hippos have been popular animals in Western culture for their rotund appearance that many consider comical.[63] Stories of hippos like Huberta who became a celebrity in South Africa in the 1930s for trekking across the country;[71] or the tale of Owen and Mzee, a hippo and tortoise who developed an intimate bond; have amused people who have bought hippo books, merchandise, and many a stuffed hippo toy.[72][73] Hippos were mentioned in the novelty Christmas song "I Want a Hippopotamus for Christmas" that became a hit for child star Gayla Peevey in 1953.[74] They also feature in the songs "The Hippopotamus" and "Hippo Encore" by Flanders and Swann, with the famous refrain Mud, Mud, Glorious Mud. They even inspired a popular board game, Hungry Hungry Hippos. Hippos have also been popular cartoon characters, where their rotund frame is used for humorous effect. The Disney film Fantasia featured a ballerina hippopotamus dancing to the opera, La Gioconda.[38] Other cartoon hippos have included Hanna-Barbera's Peter Potamus, the book and TV series George and Martha, Flavio and Marita on the Animaniacs, Pat of the French duo Pat et Stanley, The Backyardigan's Tasha, and Gloria and Moto-Moto from the Madagascar franchise. A Sesame Street cartoon from the early 1970s features a hippo who lives in the country and likes it quiet, while being disturbed when the mouse who likes it loud moves in with her.[citation needed]

The hippopotamus characters "Happy Hippos" were created in 1988 by the French designer Andre Roche [77] based in Munich, to be hidden in the "Kinder Surprise egg" of the Italian chocolate company Ferrero SpA. These characters were not placid like real hippos[contradiction] but rather cute and lively, and had such a success that they reappeared several times in different products of this company in the following years, increasing their popularity worldwide each time.[citation needed] The Nintendo Company published in the years 2001 and 2007 Game Boy adventures of them. In the game of chess, the hippopotamus lends its name to the Hippopotamus Defense, an opening system, which is generally considered weak.The River Horse is a popular outdoor sculpture at George Washington University, Washington, D.C. Botswana, Moremi National Park, Moremi Game reserve, private Reserve, Farm, chobe National park, Chobe Game Reserve, Zambia, Zambezi River, Livingstone, Zimbabwe, Kenya, Tanzania, Wildlife Conservation Project, Maramba River Lodge, South Africa, Krugger National Park. art beach blue bw california canada canon china city concert de england europe family festival film flower flowers food france friends green instagramapp iphoneography italy japan live london music nature new newyork night nikon nyc paris park party people photography portrait red sky snow square squareformat street summer sunset travel trip uk usa vacation water wedding white winter

Go to the Book with image in the Internet Archive

Title: United States Naval Medical Bulletin Vol. 16, Nos. 1-6, 1922

Creator: U.S. Navy. Bureau of Medicine and Surgery

Publisher:

Sponsor:

Contributor:

Date: 1922-01

Language: eng

  

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Table of Contents</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Number 1</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREFACE v</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTICE TO SERVICE CONTRIBUTORS vi</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SPECIAL ARTICLES:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Mosquito eradication.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander A. H. Allen, Medical Corps, U. S. N 1 </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Hospital morale.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Colonel E. L. Munson, Medical Corps, U. S. A 8</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">The pathologist as an essential factor in clinical diagnosis.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander J. Harper, Medical Corps, U. S. N 14</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Tonsillectomy, a surgical procedure.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander G. B. Trible, Medical Corps, U. S. N 17</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Cholelithiasis.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander W. A. Brums, Medical Corps, U. S. N.R. F 25</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">HISTORICAL :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">With Anson to Juan Fernandez, Part I.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander W. M. Kerr, Medical Corps, U. S. N 35 </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">EDITORIAL:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">U. S. Naval Medical Bulletin —On a correspondence course for Naval

Medical Officers —On The Danger Of Using Strong Solutions Of Phenol In The Ear 43</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">IN MEMORIAM:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Andrew Reginold Wentworth, 1859-1921 49</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">HONORS AND DISTINCTIONS 51</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">CLINICAL NOTES :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">BRONCHO-PNEUMONIA AND BRONCHOSTENOSIS FOLLOWING APPENDECTOMY.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander I. W. Jacobs, Medical Corps, U. S. N_ 57</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Report of four surgical cases.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander J. J. A. McMullin, Medical Corps, U. S. N 58</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Chronic cholecystitis.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant C. S. Norburn, Medical Corps, U. S. N 63</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">One hundred mastoid operations.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant J. W. Green, Medical Corps, U. S. N 89</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PROGRESS IN MEDICAL SCIENCES :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">General medicine. — Study of transfused blood.— Oral administration of

pituitary extract. —Causes and treatment of high blood pressure.—Pernicious

anemia. —Differential diagnosis between varicella and variola. — Predisposing

factor in diphtheria. —Chronic nephritis 71</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Surgery. —First-aid work on shore with Royal Naval Division. — Surgery

of naval wounded in hospital yachts and small craft. —Non-surgical drainage of

the biliary tract S9 Tropical medicine. —Course of migration of ascaris larvae.

—Treatment of fluke diseases. —Laboratory observations on malaria. — Leprosy.

—Tuberculosis in Hongkong. —Feeding habits of stegomyia calopus. —Mononuclear

leucocyte count in malaria 97</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Chemistry. —Experimental studies in diabetes. —Experimental studies in

diabetes. —Experiments on raw white of egg. —Antiscorbutic action of raw

potato. —Diet in hyperthyroidism. —Botulism. — Pituitary extract and histamine

in diabetes insipidus. —Protein in the cerebrospinal fluid. —Urine in pellagra.

—Acidosis in operative surgery. —Fats and Lipoids in blood after hemorrhage. —

Albumin, lymphocytic cells, and tubercle bacilli in sputum. — Nitrous oxide and

cholemia.— Lipoids in treatment of drug addiction disease.— Modification of

action of adrenaline by chloroform. — Anesthetic and convulsant effects of

gasoline vapors. —Absorption of local anesthetics through the genito-urlnary

organs. — Occult blood in the feces. —lTse of iodine for disinfecting the skin.

— Food value of various fats. —Chloride metabolism. —Urine hemolysis

coefficient. —Hemolytic substances in human urine. — Glucemia and glucosuria.

—Pharmacology of some benzyl esters.—Indican In water as an aid to hygienic

water analysis. —Relation of dextrose of blood to antipyrine. — Toxic effects

of chlorine antiseptics in</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">dogs. —Reaction to epiuephrin administered by rectum. — Renal

excretion. — Effect of water diuresis on the elimination of certain urinary

constituents 100</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Eye, eak, nose, and throat. —Eye disease due to syphilis and trypanosomiasis

among negroes of Africa. —Lung abscess following tonsillectomy 111</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTES AND COMMENTS:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Montaigne and medicine. —Venereal prophylaxis in Pacific Fleet. —

Benzyl benzoate. — Expedition of London School of Tropical Medicine to British

Guiana. —National board of medical examiners. — Papers by naval medical

officers. —Chaulmoogra oil in tuberculosis.—An operating room 100 years ago ,

133</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NURSE CORPS :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Instruction at Oteen.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Miss E. L. Hehir, Chief Nurse, U. S. N 121</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Letter From Surgeon General To Director Of Department Of Nursing,

American Red Cross 122</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">DIGEST OF DECISIONS 125</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">BOOK NOTICES 131</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">QUERIES 139</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREVENTIVE MEDICINE STATISTICS, LETTERS, ORDERS, NEW LEGISLATION,

MOVEMENTS OF OFFICERS AND NURSES 141</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Number 2</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREFACE v</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTICE TO SERVICE CONTRIBUTORS vi</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SPECIAL ARTICLES :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Size of the normal heart, a teleroentgen study.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander H. W. Smith and Lieutenant Commander W. A. Bloedorn,

Medical Corps, U. S. N 218 Physical development of midshipmen.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant E. B. Taylor, Medical Corps, U. S. N 239</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Some elements of leadership.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By E. L. Munson, Colonel, Medical Corps, U. S. A 251</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">HISTORICAL:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">With Anson to Juan Fernandez, part II.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander W. M. Kerr, Medical Corps, U. S. N<span>  </span>265</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">EDITORIAL :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">On the making of abstracts —on the expression of visual acuity in

medical reports 280</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SUGGESTED DEVICES :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A FORM " X " CARD.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Captain A. Farenholt, Medical Corps, U. S. N 283</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">CLINICAL NOTES :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Results of refraction of seventy-six midshipmen.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant F. A. Hughes, Medical Corps, U. S. N 285</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Recurrence in a case of hydatid disease.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant C. S. Norburn, Medical Corps, U. S. N 288</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A DIAGNOSTIC SIGN DIFFERENTIATING BETWEEN ERUPTIONS CAUSED BY COWPOX

VACCINATION AND THOSE DUE TO SMALLPOX AND CHICKEN POX.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander P. R. Stalnaker, Medical Corps, U. S. N 290</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Report of three "hallux valgus" (bunion ) operations, using Mayo's

technique.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander A. H. Robnett, Medical Corps, U. S. N 291</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">REPORTS :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">The hospital standardization program of the American College of Surgeons.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander R. C. Holcomb, Medical Corps, U. S. N 293</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PROGRESS IN MEDICAL SCIENCES.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">General Medicine. —Chronic myocarditis and its management. — Experiments

on the preservation of lemon juice and prevention of scurvy. —Scurvy : A system

of prevention for a polar expedition based on present-day knowledge. —Venous

puncture by means of steel needles.— Wassermann reaction 301</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Surgery. —First aid work on shore with Royal Naval Division.— Hypertrophic

tuberculosis of the ileocecal region. —Importance of examination of patients by

the anesthetist previous to anesthesia. —Experimental and histological

investigation of rectal fistulas. —Treatment of fractures of the humerus by

suspension and traction. — Fractures of the head and neck of the radius 310</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Tropical Medicine.—Oriental Sores. —Afebrile quartan malaria with

urticaria. —Three schistosomes in Natal which possibly attack man.—Cultivation

of trichomonas hominis. —Acute bacillnry dysentery. —Monilias of the

gastro-intestinal tract in relationship to sprue.—Hookworm infection in Brazil.

—Relapsing fever in Panama. —Treatment of kala-azar with some antimonial

preparations. —Human infection with Isospora hominis. —Etiology of gangosa and

its relation to papulocircinate yaws 324 Physiological Chemistry. —Ion

migration between cells and plasma. —Experimental rickets in rats. —Extraction

and concentration of vitamines. —Respiration and blood alkali during carbon

monoxide asphyxia. —Antiketogenesis. —The Effect of heat and oxidation upon

antiscorbutic vitamine.—Production of rickets by diets low in phosphorus and

fat-soluble A. vitamines. —Effect of muscular exercise upon certain common

blood constituents. — Comparative influence of green and dried plant tissue,

cabbage, orange juice, and cod liver oil on calcium assimilation. —Method for

the determination of sugar in normal urine. —Parathyroids and creatinine.

—Variations in the acid-base balance of the blood. — Thiocyanate content of the

saliva and urine in pellagra 329</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Eye, ear, nose, and throat.—Use of scarlet red emulsion in atrophic

rhinitis (ozena). Accessory sinus blindness 329</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTES AND COMMENTS:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Spiders in Medicine. —Meeting of the American Academy of Ophthalmology

and Oto-laryngology. —Meeting of the American Dietetic Association. —Japanese

medical world. —Some submarine notes. — School of Tropical Medicine at

Calcutta. —Army method of han dling syphilis. —Prophylactic vaccination for the

prevention of pneumonia 339</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NURSE CORPS 351</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">DIGEST OF DECISIONS 353</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">BOOK NOTICES 355</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">QUERIES 361</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTES ON PREVENTIVE MEDICINE, PREVENTIVE MEDICINE STATISTICS, LETTERS,

ORDERS, NEW LEGISLATION, MOVE MENTS OF OFFICERS AND NURSES 363</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Number 3</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREFACE<span>  </span>v</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTICE TO SERVICE CONTRIBUTORS VI</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SPECIAL ARTICLES :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Revaccination Against Smallpox And A Discussion Of Immunity Following

Cowpox Vaccination.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant E. Peterson, Medical Corps, U. S. N 411</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Some elements of leadership.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Colonel E. L. Munson, Medical Corps, U. S. N 433</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Hyperthyroidism.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander T. W. Reed, Medical Corps, U. S. N 454</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">HISTORICAL:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">The history of anesthesia in America.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Captain J. S. Taylor, Medical Corps, U. S. N 461</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A history of blood transfusion.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander W. M. Kerr, Medical Corps, U. S. N__ 465</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">EDITORIAL :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">On education for our idle hours. On line of duty 477</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SUGGESTED DEVICES :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">The technique of making and staining frozen sections.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander J. Harper, Medical Corps, U. S. N 481</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">CLINICAL NOTES :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Neurosyphilis.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander H. Butts and Lieutenant W. M. Alberty, Medical

Corps, U. S. N 483</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Treatment of surgical ulcers of stomach and duodenum.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander J. J. A. McMullin, Medical Corps, U. S. N 497</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Foreign body in the right lower bronchus.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant J. W. Green, Medical Corps, U. S. N 506</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PROGRESS IN MEDICAL SCIENCES :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">General medicine. —Treatment of gastric ulcer. —Meningococcus

infection. —Syphilis of the heart. — Standard of cure in gonorrhea. —

Provocative procedures in diagnosis of syphilis.—Intraspinal treatment of

neurosyphilis. —Dissemination of spirochseta pallida from the primary focus of

infection. —Abdominal syphilis.—Pulmonary syphilis.—Diagnosis and treatment of

early syphilis. —Reinfection and curability in syphilis. —Local and general

spirochetosis. —Use of arsphenamine in nonsyphilitic diseases.—Prophylaxis of

syphilis with arsphenamine 509</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Surgery. —Epitheliomata of thymic origin.—Surgical treatment of

epithelioma of the Hp. —Light and heat treatment of epididymitis-- 521</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Tropical medicine. — Recent progress in medical zoology. — Intravenous

injection of antimony tartrate in bilharzia disease.—Complexion of malaria

cases. —Standard treatment of malaria 524</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Physiological chemistry. —Determination of the basal metabolism from

the carbon-dioxide elimination.—Supplementary values of proteins. — Studies in

the vitamine content. — Sampling bottle for Sins analysis. —Fat-soluble

vitamine. —Effect of hydrochloric acid ingestion upon composition of urine in

man 530</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Eye, ear, nose, and throat.—Conditions predisposing to hemorrhage in

tonsil operations. —Statistical record of serious and fatal hemorrhage

following operation on the tonsil 540</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTES AND COMMENTS:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Tenth revision of the United States Pharmacopoeia.— Vaccine in the

prevention of pneumonia. -—Three old books. —Removal of stains from wash goods.

—Health of the French Mediterranean fleet during the war. —Treatment of

poisoning due to the venom of a snake. —Annual health report of the German Navy

543</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NURSE CORPS 561</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">DIGEST OF DECISIONS 567</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">BOOK NOTICES 569</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">QUERIES 572</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREVENTIVE MEDICINE, STATISTICS, LETTERS, ORDERS, NEW LEGISLATION,

MOVEMENTS OF OFFICERS AND NURSES 574</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Number 4</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREFACE , v</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTICE TO SERVICE CONTRIBUTORS VI</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SPECIAL ARTICLES:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Medical aspects of gas warfare.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant G. H. Mankin, Medical Corps, U. S. N 641</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">The alcohol question in Sweden.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander J. S. Taylor, Medical Corps, U. S. N 649</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">The social service worker and the ex-service man.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant J. T. Boone, Medical Corps, U. S. N 653</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Review of the reorganization of the sanitary and public health work in

the Dominican Republic under the United States military government of Santo

Domingo.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander R. Hayden, Medical Corps, U. S. N 657</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Some lessons of the World War in medicine and surgery from the German

viewpoint.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander W. S. Bainbridge, Medical Corps, U. S. N. R, F 672</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">HISTORICAL :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">James Inderwick, Surgeon, United States Navy, 1818-1815.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Captain F. L. Pleadwell, Medical Corps, U. S. N 699</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">EDITORIAL :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">The three horsemen and the body louse 713</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">CLINICAL NOTES:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Note on the use of Mercurochrome-220 within the peritoneum.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander Lucius W. Johnson, Medical Corps,</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">U. S. N 717</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Ten-second sterilization.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander H. E. Harvey, Dental Corps, U. S. N. 717</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">The use of Mercurochrome-220 in infected wounds.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant W. L. Martin, Medical Corps, U. S. N 718</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Notes on motor points.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander W. S. Bainbridge, Medical Corps, U. S. N. R. F__ 719</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PROGRESS IN MEDICAL SCIENCES: </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Tropical medicine. —Treatment of human trypanosomiasis with

tryparsamide. —Wassermann reaction in malaria. —Wassermann reaction in malarial

fevers. — Rat repression by sexual selection. — Case of tubercular leprosy

treated by intravenous injections of stibenyl. —Bismuth-emetine treatment for

amebic dysentery and amebiasis. —Malaria incidence on the Canal

Zone.—Experiment of leper segregation in the Philippines.— Detection of Lamblla

lntestlnalls by means of duodenal tube. —Balantidium coll and pernicious

anemia. —Tropical myositis. —Differential diagnosis of the common intestinal

amebae of man.—Contributions to the biology of the Danish culicidae. —Treatment

of sleeping sickness. —Bilharzia disease treated with tartar emetic.

—Iso-agglutination group percentages of Filipino bloods.—Public health in the

Dominican Republic , 721</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Chemistry. —Metabolism of the man of the Tropics. —Disturbances in the

development of mammalian embryos caused by radium emanation. —Ammonia content

of the blood and its bearing on the mechanism of acid neutralization in the

animal organism 735</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTES AND COMMENTS:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Dispersion of flies by flight.—International Association of the History

of Medicine. —Incineration of latrine contents. —Far Eastern Association of

Tropical Medicine. —Care of the sick and wounded of the North Russia

Expeditionary Force. —Manufacture of soft soap. —the upkeep of rats. —Erratum

739</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NURSE CORPS 749</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">DIGEST OF DECISIONS 7B9</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">BOOK NOTICES 768</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">QUERIES<span>   </span>767</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREVENTIVE MEDICINE, STATISTICS, LETTERS, ORDERS, NEW LEGISLATION,

MOVEMENTS OF OFFICERS AND NURSES 769</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Number 5</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREFACE V</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTICE TO SERVICE CONTRIBUTORS vi</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SPECIAL ARTICLES :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">ON THE ENDOCRINE GLANDS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Surgeon Captain Masaharu Kojlma, Imperial Japanese Navy. 821</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Aviation medicine in the United States Navy.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant J. F. Neuberger, Medical Corps, U. S. N 834</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Pyelonephritis : A critical review of one hundred cases.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander O. C. Foote, Medical Corps, U. S. N— 844</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Recurrent hernia.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander Lucius W. Johnson, Medical Corps, U. S. N 849</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Meningococcus septicemia.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander W. A. Bloedorn, Medical Corps, U. S. N 855</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">HISTORICAL:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Peter St. Medard, surgeon in the Navy of the United States.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander W. M. Kerr, Medical Corps, U. S. N. 867</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">The study of medicine in Strasbourg.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Captain J. S. Taylor, Medical Corps, U. S. N 874</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">EDITORIAL :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">On the acquisition of useless knowledge. —ON the conservation of gauze

877</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">CLINICAL NOTES :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Report of a case of shark bite.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander C. R. Baker and Lieutenant C. W. Rose, Medical

Corps, U. S. N 881</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A practical treatment of acute ulcerative gingivitis.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant C. R. Wells, Dental Corps, U. S. N 885</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">REPORTS: </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A report of the international standardization of sera 885</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PROGRESS IN MEDICAL SCIENCES:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">General Medicine. —Metabolism in pellagra. —-One thousand one hundred

goiters in one thousand seven hundred eighty-three persons. —Diphtheria carriers

and their treatment with mercurochrome.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">—Method for determination of death by drowning. — Strain in

Spirochetes. —Hereditary blood qualities 889</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Surgery. —Peri-arterial sympathetlcs. —Factors in bone repair.

—Operations on the gall bladder and bile ducts. —Operative procedures for

different kinds of goiter. —Varicose ulcers. —Cancer of the tongue 896</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Tropical Medicine.—La maladie des oedemes a Java. —Dysentery.— Dysentery.

—Natural immunity of wild rats to plague.— Charcot-Leyden crystals in the

stools as an aid to the diagnosis of entamoebic</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">dysentery. —Glycosuria of malarial origin. —Dermatitis venenata

produced by an irritant present in stem sap of the mango. —Treatment of

trichuriasis with Leche de Higueron. — Malaria in Eastern Cuba. —Dhobie itch

produced by inoculating with a culture of Epidermophyton rubrtim. —Ueber eineu

Fall von Filaria loa 901</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTES AND COMMENTS :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">The immunization of adults with the diphtheria toxin-antitoxin mixture.

— Smallpox in the colony of Bahamas. — Meeting of Royal Society of Tropical

Medicine and Hygiene. —Curative effects of chaulmoogra oil derivatives on

leprosy. — Virulence of tubercle bacilli under changing environment. —Malaria

in Bulgaria. — Methods of drainage. — Use of white lead in paints. —A method of

preventive inoculation for smallpox. — Paper on hospital ship ventilation. —</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Papers by medical officers of the Navy 907</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NURSE CORPS 919</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">DIGEST OF DECISIONS 923</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">BOOK NOTICES 929</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">QUERIES 935</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREVENTIVE MEDICINE, STATISTICS, LETTERS, ORDERS, NEW LEGISLATION,

MOVEMENTS OF OFFICERS AND NURSES 937</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Number 6</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREFACE v</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTICE TO SERVICE CONTRIBUTORS vi</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SPECIAL ARTICLES :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Hydrogen-ion concentration.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander C. W. O. Bunker. Medical Corps, U. S. N 973</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Aviation medicine in the United States Navy.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant J. F. Neuberger, Medical Corps, U. S. N 083</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Developments in the diagnosis and treatment of syphilis.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant L. W. Shaffer, Medical Corps, U. S. N 1011</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">HISTORICAL:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">The old anatomical school at Padua.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander W. M. Kerr, Medical Corps, U. S. N- 1015</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">EDITORIAL:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">On carbon monoxide asphyxia. —On the habit of reading 1029</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SUGGESTED DEVICES :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">The method of preparing colloidal gold solution used at the U. S. Naval

Medical School.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant J. Harper, Medical Corps, U. S. N., and Chief Pharmacist

C. Schaffer. Medical Corps, U. S. N 1037</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PROGRESS IN MEDICAL SCIENCES:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">General Medicine. —Prognostic significance of persistent high blood

pressure. — Standardization of the Wassermann reaction. —Modern conceptions of

the treatment of syphilis. —Treatment of neurosyphilis. —Treatment of visceral

syphilis. —New technique for staining Treponema pallida. —Method of

demonstration of spirochteta pallida in the tissues 1041</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Surgery. —Postoperative pulmonary complications 1051</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Tropical Medicine. —Activities of infective hookworm larvae in the

soil. —Use of carbon letrachlorid for removal of hookworms — Hemotoxins from

parasitic worms. — Specific treatment of malaria. —Malaria epidemic in Naras in

1918. —Dysentery. — Une nouvelle maladie a bacilles acido-resistants qui n'est

ni la tuberculose, ni la lepre. —Malaria epidemic caused by M. Sinensis. —

Vesical bilharziasis, indigenous to Portugal. —An exceptional tropical

ulceration 1053</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Physiological Chemistry. —Action of antispasmodic drugs on the

bronchus. —Methanol on trial.— Nature of beriberi and related diseases. —Ethyl

alcohol, caffeine, and nicotine on the behavior of rats in a maze. —Biliary

obstruction required to produce Jaundice.—Transfused blood.— Anthelmintics and

hookworm treat ment.—Chemotherapy. —Influence of morphine in experimental

septicemia.— Fumigation with formaldehyde. —Lesions in bones of rats suffering

from uncomplicated berberi 1062</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Eye, ear, nose, and throat. —Nose, throat, and ear requirements of

airmen. —Septicemia and death following streptococcus tonsillitis.— Gangosa.—

Iritis caused by focal infection.— Episcleritis.. 1065</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTES AND COMMENTS :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Toxic effects of picric acid. —Chemical warfare. — Destruction of the

dirigible ZR-2.—Outbreaks of plague in South Africa. —Relation of species of

rat fleas to the spread of plague. —Diary of William</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Clift. —Medicine in art. —Therapeutic index of silver arsphenamin.

—Antiscorbutic vitamins contained in dehydrated fruits. — Hookworm survey.

—Treatment of amoebic dysentery 1071</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">REPORTS :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Report of the health of the Royal Air Force for the year 1920. 1083</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NURSE CORPS 1095</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">DIGEST OF DECISIONS 1099</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">BOOK NOTICES 1103</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">QUERIES 1111</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREVENTIVE MEDICINE STATISTICS, LETTERS, ORDERS 1115</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">INDEX i</p>

  

If you have questions concerning reproductions, please contact the Contributing Library.

 

Note: The colors, contrast and appearance of these illustrations are unlikely to be true to life. They are derived from scanned images that have been enhanced for machine interpretation and have been altered from their originals.

 

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See all images from this book

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Notice the pink rosy endocrine part of the pancreas. The beta cells secrete insulin and the alpha cells secrete glucagon for uptake by the surround capillaries.

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Title: United States Naval Medical Bulletin Vol. 16, Nos. 1-6, 1922

Creator: U.S. Navy. Bureau of Medicine and Surgery

Publisher:

Sponsor:

Contributor:

Date: 1922-01

Language: eng

  

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Table of Contents</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Number 1</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREFACE v</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTICE TO SERVICE CONTRIBUTORS vi</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SPECIAL ARTICLES:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Mosquito eradication.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander A. H. Allen, Medical Corps, U. S. N 1 </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Hospital morale.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Colonel E. L. Munson, Medical Corps, U. S. A 8</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">The pathologist as an essential factor in clinical diagnosis.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander J. Harper, Medical Corps, U. S. N 14</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Tonsillectomy, a surgical procedure.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander G. B. Trible, Medical Corps, U. S. N 17</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Cholelithiasis.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander W. A. Brums, Medical Corps, U. S. N.R. F 25</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">HISTORICAL :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">With Anson to Juan Fernandez, Part I.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander W. M. Kerr, Medical Corps, U. S. N 35 </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">EDITORIAL:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">U. S. Naval Medical Bulletin —On a correspondence course for Naval

Medical Officers —On The Danger Of Using Strong Solutions Of Phenol In The Ear 43</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">IN MEMORIAM:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Andrew Reginold Wentworth, 1859-1921 49</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">HONORS AND DISTINCTIONS 51</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">CLINICAL NOTES :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">BRONCHO-PNEUMONIA AND BRONCHOSTENOSIS FOLLOWING APPENDECTOMY.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander I. W. Jacobs, Medical Corps, U. S. N_ 57</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Report of four surgical cases.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander J. J. A. McMullin, Medical Corps, U. S. N 58</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Chronic cholecystitis.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant C. S. Norburn, Medical Corps, U. S. N 63</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">One hundred mastoid operations.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant J. W. Green, Medical Corps, U. S. N 89</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PROGRESS IN MEDICAL SCIENCES :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">General medicine. — Study of transfused blood.— Oral administration of

pituitary extract. —Causes and treatment of high blood pressure.—Pernicious

anemia. —Differential diagnosis between varicella and variola. — Predisposing

factor in diphtheria. —Chronic nephritis 71</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Surgery. —First-aid work on shore with Royal Naval Division. — Surgery

of naval wounded in hospital yachts and small craft. —Non-surgical drainage of

the biliary tract S9 Tropical medicine. —Course of migration of ascaris larvae.

—Treatment of fluke diseases. —Laboratory observations on malaria. — Leprosy.

—Tuberculosis in Hongkong. —Feeding habits of stegomyia calopus. —Mononuclear

leucocyte count in malaria 97</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Chemistry. —Experimental studies in diabetes. —Experimental studies in

diabetes. —Experiments on raw white of egg. —Antiscorbutic action of raw

potato. —Diet in hyperthyroidism. —Botulism. — Pituitary extract and histamine

in diabetes insipidus. —Protein in the cerebrospinal fluid. —Urine in pellagra.

—Acidosis in operative surgery. —Fats and Lipoids in blood after hemorrhage. —

Albumin, lymphocytic cells, and tubercle bacilli in sputum. — Nitrous oxide and

cholemia.— Lipoids in treatment of drug addiction disease.— Modification of

action of adrenaline by chloroform. — Anesthetic and convulsant effects of

gasoline vapors. —Absorption of local anesthetics through the genito-urlnary

organs. — Occult blood in the feces. —lTse of iodine for disinfecting the skin.

— Food value of various fats. —Chloride metabolism. —Urine hemolysis

coefficient. —Hemolytic substances in human urine. — Glucemia and glucosuria.

—Pharmacology of some benzyl esters.—Indican In water as an aid to hygienic

water analysis. —Relation of dextrose of blood to antipyrine. — Toxic effects

of chlorine antiseptics in</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">dogs. —Reaction to epiuephrin administered by rectum. — Renal

excretion. — Effect of water diuresis on the elimination of certain urinary

constituents 100</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Eye, eak, nose, and throat. —Eye disease due to syphilis and trypanosomiasis

among negroes of Africa. —Lung abscess following tonsillectomy 111</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTES AND COMMENTS:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Montaigne and medicine. —Venereal prophylaxis in Pacific Fleet. —

Benzyl benzoate. — Expedition of London School of Tropical Medicine to British

Guiana. —National board of medical examiners. — Papers by naval medical

officers. —Chaulmoogra oil in tuberculosis.—An operating room 100 years ago ,

133</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NURSE CORPS :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Instruction at Oteen.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Miss E. L. Hehir, Chief Nurse, U. S. N 121</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Letter From Surgeon General To Director Of Department Of Nursing,

American Red Cross 122</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">DIGEST OF DECISIONS 125</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">BOOK NOTICES 131</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">QUERIES 139</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREVENTIVE MEDICINE STATISTICS, LETTERS, ORDERS, NEW LEGISLATION,

MOVEMENTS OF OFFICERS AND NURSES 141</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Number 2</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREFACE v</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTICE TO SERVICE CONTRIBUTORS vi</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SPECIAL ARTICLES :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Size of the normal heart, a teleroentgen study.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander H. W. Smith and Lieutenant Commander W. A. Bloedorn,

Medical Corps, U. S. N 218 Physical development of midshipmen.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant E. B. Taylor, Medical Corps, U. S. N 239</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Some elements of leadership.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By E. L. Munson, Colonel, Medical Corps, U. S. A 251</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">HISTORICAL:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">With Anson to Juan Fernandez, part II.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander W. M. Kerr, Medical Corps, U. S. N<span>  </span>265</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">EDITORIAL :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">On the making of abstracts —on the expression of visual acuity in

medical reports 280</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SUGGESTED DEVICES :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A FORM " X " CARD.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Captain A. Farenholt, Medical Corps, U. S. N 283</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">CLINICAL NOTES :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Results of refraction of seventy-six midshipmen.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant F. A. Hughes, Medical Corps, U. S. N 285</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Recurrence in a case of hydatid disease.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant C. S. Norburn, Medical Corps, U. S. N 288</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A DIAGNOSTIC SIGN DIFFERENTIATING BETWEEN ERUPTIONS CAUSED BY COWPOX

VACCINATION AND THOSE DUE TO SMALLPOX AND CHICKEN POX.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander P. R. Stalnaker, Medical Corps, U. S. N 290</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Report of three "hallux valgus" (bunion ) operations, using Mayo's

technique.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander A. H. Robnett, Medical Corps, U. S. N 291</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">REPORTS :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">The hospital standardization program of the American College of Surgeons.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander R. C. Holcomb, Medical Corps, U. S. N 293</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PROGRESS IN MEDICAL SCIENCES.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">General Medicine. —Chronic myocarditis and its management. — Experiments

on the preservation of lemon juice and prevention of scurvy. —Scurvy : A system

of prevention for a polar expedition based on present-day knowledge. —Venous

puncture by means of steel needles.— Wassermann reaction 301</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Surgery. —First aid work on shore with Royal Naval Division.— Hypertrophic

tuberculosis of the ileocecal region. —Importance of examination of patients by

the anesthetist previous to anesthesia. —Experimental and histological

investigation of rectal fistulas. —Treatment of fractures of the humerus by

suspension and traction. — Fractures of the head and neck of the radius 310</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Tropical Medicine.—Oriental Sores. —Afebrile quartan malaria with

urticaria. —Three schistosomes in Natal which possibly attack man.—Cultivation

of trichomonas hominis. —Acute bacillnry dysentery. —Monilias of the

gastro-intestinal tract in relationship to sprue.—Hookworm infection in Brazil.

—Relapsing fever in Panama. —Treatment of kala-azar with some antimonial

preparations. —Human infection with Isospora hominis. —Etiology of gangosa and

its relation to papulocircinate yaws 324 Physiological Chemistry. —Ion

migration between cells and plasma. —Experimental rickets in rats. —Extraction

and concentration of vitamines. —Respiration and blood alkali during carbon

monoxide asphyxia. —Antiketogenesis. —The Effect of heat and oxidation upon

antiscorbutic vitamine.—Production of rickets by diets low in phosphorus and

fat-soluble A. vitamines. —Effect of muscular exercise upon certain common

blood constituents. — Comparative influence of green and dried plant tissue,

cabbage, orange juice, and cod liver oil on calcium assimilation. —Method for

the determination of sugar in normal urine. —Parathyroids and creatinine.

—Variations in the acid-base balance of the blood. — Thiocyanate content of the

saliva and urine in pellagra 329</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Eye, ear, nose, and throat.—Use of scarlet red emulsion in atrophic

rhinitis (ozena). Accessory sinus blindness 329</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTES AND COMMENTS:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Spiders in Medicine. —Meeting of the American Academy of Ophthalmology

and Oto-laryngology. —Meeting of the American Dietetic Association. —Japanese

medical world. —Some submarine notes. — School of Tropical Medicine at

Calcutta. —Army method of han dling syphilis. —Prophylactic vaccination for the

prevention of pneumonia 339</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NURSE CORPS 351</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">DIGEST OF DECISIONS 353</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">BOOK NOTICES 355</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">QUERIES 361</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTES ON PREVENTIVE MEDICINE, PREVENTIVE MEDICINE STATISTICS, LETTERS,

ORDERS, NEW LEGISLATION, MOVE MENTS OF OFFICERS AND NURSES 363</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Number 3</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREFACE<span>  </span>v</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTICE TO SERVICE CONTRIBUTORS VI</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SPECIAL ARTICLES :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Revaccination Against Smallpox And A Discussion Of Immunity Following

Cowpox Vaccination.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant E. Peterson, Medical Corps, U. S. N 411</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Some elements of leadership.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Colonel E. L. Munson, Medical Corps, U. S. N 433</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Hyperthyroidism.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander T. W. Reed, Medical Corps, U. S. N 454</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">HISTORICAL:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">The history of anesthesia in America.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Captain J. S. Taylor, Medical Corps, U. S. N 461</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A history of blood transfusion.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander W. M. Kerr, Medical Corps, U. S. N__ 465</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">EDITORIAL :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">On education for our idle hours. On line of duty 477</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SUGGESTED DEVICES :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">The technique of making and staining frozen sections.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander J. Harper, Medical Corps, U. S. N 481</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">CLINICAL NOTES :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Neurosyphilis.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander H. Butts and Lieutenant W. M. Alberty, Medical

Corps, U. S. N 483</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Treatment of surgical ulcers of stomach and duodenum.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander J. J. A. McMullin, Medical Corps, U. S. N 497</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Foreign body in the right lower bronchus.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant J. W. Green, Medical Corps, U. S. N 506</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PROGRESS IN MEDICAL SCIENCES :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">General medicine. —Treatment of gastric ulcer. —Meningococcus

infection. —Syphilis of the heart. — Standard of cure in gonorrhea. —

Provocative procedures in diagnosis of syphilis.—Intraspinal treatment of

neurosyphilis. —Dissemination of spirochseta pallida from the primary focus of

infection. —Abdominal syphilis.—Pulmonary syphilis.—Diagnosis and treatment of

early syphilis. —Reinfection and curability in syphilis. —Local and general

spirochetosis. —Use of arsphenamine in nonsyphilitic diseases.—Prophylaxis of

syphilis with arsphenamine 509</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Surgery. —Epitheliomata of thymic origin.—Surgical treatment of

epithelioma of the Hp. —Light and heat treatment of epididymitis-- 521</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Tropical medicine. — Recent progress in medical zoology. — Intravenous

injection of antimony tartrate in bilharzia disease.—Complexion of malaria

cases. —Standard treatment of malaria 524</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Physiological chemistry. —Determination of the basal metabolism from

the carbon-dioxide elimination.—Supplementary values of proteins. — Studies in

the vitamine content. — Sampling bottle for Sins analysis. —Fat-soluble

vitamine. —Effect of hydrochloric acid ingestion upon composition of urine in

man 530</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Eye, ear, nose, and throat.—Conditions predisposing to hemorrhage in

tonsil operations. —Statistical record of serious and fatal hemorrhage

following operation on the tonsil 540</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTES AND COMMENTS:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Tenth revision of the United States Pharmacopoeia.— Vaccine in the

prevention of pneumonia. -—Three old books. —Removal of stains from wash goods.

—Health of the French Mediterranean fleet during the war. —Treatment of

poisoning due to the venom of a snake. —Annual health report of the German Navy

543</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NURSE CORPS 561</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">DIGEST OF DECISIONS 567</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">BOOK NOTICES 569</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">QUERIES 572</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREVENTIVE MEDICINE, STATISTICS, LETTERS, ORDERS, NEW LEGISLATION,

MOVEMENTS OF OFFICERS AND NURSES 574</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Number 4</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREFACE , v</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTICE TO SERVICE CONTRIBUTORS VI</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SPECIAL ARTICLES:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Medical aspects of gas warfare.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant G. H. Mankin, Medical Corps, U. S. N 641</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">The alcohol question in Sweden.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander J. S. Taylor, Medical Corps, U. S. N 649</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">The social service worker and the ex-service man.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant J. T. Boone, Medical Corps, U. S. N 653</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Review of the reorganization of the sanitary and public health work in

the Dominican Republic under the United States military government of Santo

Domingo.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander R. Hayden, Medical Corps, U. S. N 657</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Some lessons of the World War in medicine and surgery from the German

viewpoint.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander W. S. Bainbridge, Medical Corps, U. S. N. R, F 672</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">HISTORICAL :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">James Inderwick, Surgeon, United States Navy, 1818-1815.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Captain F. L. Pleadwell, Medical Corps, U. S. N 699</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">EDITORIAL :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">The three horsemen and the body louse 713</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">CLINICAL NOTES:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Note on the use of Mercurochrome-220 within the peritoneum.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander Lucius W. Johnson, Medical Corps,</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">U. S. N 717</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Ten-second sterilization.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander H. E. Harvey, Dental Corps, U. S. N. 717</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">The use of Mercurochrome-220 in infected wounds.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant W. L. Martin, Medical Corps, U. S. N 718</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Notes on motor points.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander W. S. Bainbridge, Medical Corps, U. S. N. R. F__ 719</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PROGRESS IN MEDICAL SCIENCES: </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Tropical medicine. —Treatment of human trypanosomiasis with

tryparsamide. —Wassermann reaction in malaria. —Wassermann reaction in malarial

fevers. — Rat repression by sexual selection. — Case of tubercular leprosy

treated by intravenous injections of stibenyl. —Bismuth-emetine treatment for

amebic dysentery and amebiasis. —Malaria incidence on the Canal

Zone.—Experiment of leper segregation in the Philippines.— Detection of Lamblla

lntestlnalls by means of duodenal tube. —Balantidium coll and pernicious

anemia. —Tropical myositis. —Differential diagnosis of the common intestinal

amebae of man.—Contributions to the biology of the Danish culicidae. —Treatment

of sleeping sickness. —Bilharzia disease treated with tartar emetic.

—Iso-agglutination group percentages of Filipino bloods.—Public health in the

Dominican Republic , 721</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Chemistry. —Metabolism of the man of the Tropics. —Disturbances in the

development of mammalian embryos caused by radium emanation. —Ammonia content

of the blood and its bearing on the mechanism of acid neutralization in the

animal organism 735</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTES AND COMMENTS:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Dispersion of flies by flight.—International Association of the History

of Medicine. —Incineration of latrine contents. —Far Eastern Association of

Tropical Medicine. —Care of the sick and wounded of the North Russia

Expeditionary Force. —Manufacture of soft soap. —the upkeep of rats. —Erratum

739</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NURSE CORPS 749</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">DIGEST OF DECISIONS 7B9</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">BOOK NOTICES 768</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">QUERIES<span>   </span>767</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREVENTIVE MEDICINE, STATISTICS, LETTERS, ORDERS, NEW LEGISLATION,

MOVEMENTS OF OFFICERS AND NURSES 769</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Number 5</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREFACE V</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTICE TO SERVICE CONTRIBUTORS vi</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SPECIAL ARTICLES :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">ON THE ENDOCRINE GLANDS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Surgeon Captain Masaharu Kojlma, Imperial Japanese Navy. 821</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Aviation medicine in the United States Navy.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant J. F. Neuberger, Medical Corps, U. S. N 834</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Pyelonephritis : A critical review of one hundred cases.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander O. C. Foote, Medical Corps, U. S. N— 844</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Recurrent hernia.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander Lucius W. Johnson, Medical Corps, U. S. N 849</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Meningococcus septicemia.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander W. A. Bloedorn, Medical Corps, U. S. N 855</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">HISTORICAL:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Peter St. Medard, surgeon in the Navy of the United States.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander W. M. Kerr, Medical Corps, U. S. N. 867</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">The study of medicine in Strasbourg.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Captain J. S. Taylor, Medical Corps, U. S. N 874</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">EDITORIAL :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">On the acquisition of useless knowledge. —ON the conservation of gauze

877</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">CLINICAL NOTES :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Report of a case of shark bite.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander C. R. Baker and Lieutenant C. W. Rose, Medical

Corps, U. S. N 881</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A practical treatment of acute ulcerative gingivitis.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant C. R. Wells, Dental Corps, U. S. N 885</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">REPORTS: </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A report of the international standardization of sera 885</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PROGRESS IN MEDICAL SCIENCES:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">General Medicine. —Metabolism in pellagra. —-One thousand one hundred

goiters in one thousand seven hundred eighty-three persons. —Diphtheria carriers

and their treatment with mercurochrome.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">—Method for determination of death by drowning. — Strain in

Spirochetes. —Hereditary blood qualities 889</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Surgery. —Peri-arterial sympathetlcs. —Factors in bone repair.

—Operations on the gall bladder and bile ducts. —Operative procedures for

different kinds of goiter. —Varicose ulcers. —Cancer of the tongue 896</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Tropical Medicine.—La maladie des oedemes a Java. —Dysentery.— Dysentery.

—Natural immunity of wild rats to plague.— Charcot-Leyden crystals in the

stools as an aid to the diagnosis of entamoebic</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">dysentery. —Glycosuria of malarial origin. —Dermatitis venenata

produced by an irritant present in stem sap of the mango. —Treatment of

trichuriasis with Leche de Higueron. — Malaria in Eastern Cuba. —Dhobie itch

produced by inoculating with a culture of Epidermophyton rubrtim. —Ueber eineu

Fall von Filaria loa 901</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTES AND COMMENTS :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">The immunization of adults with the diphtheria toxin-antitoxin mixture.

— Smallpox in the colony of Bahamas. — Meeting of Royal Society of Tropical

Medicine and Hygiene. —Curative effects of chaulmoogra oil derivatives on

leprosy. — Virulence of tubercle bacilli under changing environment. —Malaria

in Bulgaria. — Methods of drainage. — Use of white lead in paints. —A method of

preventive inoculation for smallpox. — Paper on hospital ship ventilation. —</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Papers by medical officers of the Navy 907</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NURSE CORPS 919</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">DIGEST OF DECISIONS 923</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">BOOK NOTICES 929</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">QUERIES 935</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREVENTIVE MEDICINE, STATISTICS, LETTERS, ORDERS, NEW LEGISLATION,

MOVEMENTS OF OFFICERS AND NURSES 937</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Number 6</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREFACE v</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTICE TO SERVICE CONTRIBUTORS vi</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SPECIAL ARTICLES :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Hydrogen-ion concentration.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander C. W. O. Bunker. Medical Corps, U. S. N 973</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Aviation medicine in the United States Navy.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant J. F. Neuberger, Medical Corps, U. S. N 083</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Developments in the diagnosis and treatment of syphilis.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant L. W. Shaffer, Medical Corps, U. S. N 1011</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">HISTORICAL:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">The old anatomical school at Padua.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant Commander W. M. Kerr, Medical Corps, U. S. N- 1015</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">EDITORIAL:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">On carbon monoxide asphyxia. —On the habit of reading 1029</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SUGGESTED DEVICES :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">The method of preparing colloidal gold solution used at the U. S. Naval

Medical School.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieutenant J. Harper, Medical Corps, U. S. N., and Chief Pharmacist

C. Schaffer. Medical Corps, U. S. N 1037</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PROGRESS IN MEDICAL SCIENCES:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">General Medicine. —Prognostic significance of persistent high blood

pressure. — Standardization of the Wassermann reaction. —Modern conceptions of

the treatment of syphilis. —Treatment of neurosyphilis. —Treatment of visceral

syphilis. —New technique for staining Treponema pallida. —Method of

demonstration of spirochteta pallida in the tissues 1041</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Surgery. —Postoperative pulmonary complications 1051</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Tropical Medicine. —Activities of infective hookworm larvae in the

soil. —Use of carbon letrachlorid for removal of hookworms — Hemotoxins from

parasitic worms. — Specific treatment of malaria. —Malaria epidemic in Naras in

1918. —Dysentery. — Une nouvelle maladie a bacilles acido-resistants qui n'est

ni la tuberculose, ni la lepre. —Malaria epidemic caused by M. Sinensis. —

Vesical bilharziasis, indigenous to Portugal. —An exceptional tropical

ulceration 1053</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Physiological Chemistry. —Action of antispasmodic drugs on the

bronchus. —Methanol on trial.— Nature of beriberi and related diseases. —Ethyl

alcohol, caffeine, and nicotine on the behavior of rats in a maze. —Biliary

obstruction required to produce Jaundice.—Transfused blood.— Anthelmintics and

hookworm treat ment.—Chemotherapy. —Influence of morphine in experimental

septicemia.— Fumigation with formaldehyde. —Lesions in bones of rats suffering

from uncomplicated berberi 1062</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Eye, ear, nose, and throat. —Nose, throat, and ear requirements of

airmen. —Septicemia and death following streptococcus tonsillitis.— Gangosa.—

Iritis caused by focal infection.— Episcleritis.. 1065</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTES AND COMMENTS :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Toxic effects of picric acid. —Chemical warfare. — Destruction of the

dirigible ZR-2.—Outbreaks of plague in South Africa. —Relation of species of

rat fleas to the spread of plague. —Diary of William</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Clift. —Medicine in art. —Therapeutic index of silver arsphenamin.

—Antiscorbutic vitamins contained in dehydrated fruits. — Hookworm survey.

—Treatment of amoebic dysentery 1071</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">REPORTS :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Report of the health of the Royal Air Force for the year 1920. 1083</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NURSE CORPS 1095</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">DIGEST OF DECISIONS 1099</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">BOOK NOTICES 1103</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">QUERIES 1111</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREVENTIVE MEDICINE STATISTICS, LETTERS, ORDERS 1115</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">INDEX i</p>

  

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Title: United States Naval Medical Bulletin Vol. 20, Nos. 1-6, 1924

Creator: U.S. Navy. Bureau of Medicine and Surgery

Publisher:

Sponsor:

Contributor:

Date: 1924-01

Language: eng

  

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Table of Contents</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> Number 1</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> PREFACE -------------------------------- - - ------ ------- V</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTICE TO SERVICE CONTRIBUTORS____________________________ VI</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SPECIAL ARTICLES:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Climatic Bubo.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander C. S. Butler, Medical Corps, U. S. Navy______ 1</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTES ON 350 APPENDECTOMIES.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. Commander Lucius W. Johnson, Medical Corps, U. S .. Navy------------------------

-- 7</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">CLINICAL TRIAL OF THE ELLIS TEST FOR TUBERCULOSIS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. D. Ferguson, Medical Corps, U. S. Navy____________ 17</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">CANCER IN ST. CROIX, VIRGIN ISLANDS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. C. B. Van Gaasbeek, Medical Corps, U. S. Navy______ 31</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SUGAR IN URINE.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Lieut. Commander C. W. 0. Bunker, Medical Corps, U. S. Navy, and

Pharmacist's Mate R. L. Thrasher, first class, U. S. Navy------------------

--------------- -------------------- 35</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">CLINICAL NOTES :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">ENDOTHELIOMA.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. L. H. Williams, Medical Corps, U. S. Navy__________ 39</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">GLANDERS IN MAN.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. L. H. Williams and Lieut. R. C. Satterlee, Medical Corps, U.

S. Navy__________________ 41</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">ACUTE APPENDICITIS WITHIN A HERNIA SAC.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. C. B. Van Gaasbeek, Medical Corps, U. S. Navy______ 43</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">CHANCRE OF THE PALMAR SURFACE OF THE HAND.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. (J. G.) J. E. Root, jr., Medical Corps, U. S. Navy____ 44</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">RECURRENT DIFFUSE SCLERODERMA, A CASE OF.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. C. W. Lane, Medical Corps, U. S. Navy_____________ 45</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">ACUTE YELLOW ATROPHY OF LIVER, A CASE OF.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. G. L. McClintock, Medical Corps, U. S. Navy________ 49</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTES AND COMMENTS:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Meeting of the Association of Military Surgeons.-Protection of capital

ships against poison gas.-Thomas Wakley and the Lancet.- Diathermy in

pneumonia.-Prophylactic injection of normal serum against measles.-Lamblial

dysentery treated with carbon tetrachloride.-Endocrine survey____________ 53</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NAVY NURSE CORPS--------------------------------------------- 75</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">INSTRUCTIONS TO MEDICAL OFFICERS:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Shortage in petty-officer ratings in Hospital Corps.-Haemostatic forceps

and surgical needles carried in stock at the medical supply depot-Form N. M. S.

F. (revised) .-Policy of U. S. Employees' Compensation Commission regarding

employees suffering from occupational diseases; now considered compensable and

entitled to treatment.-Hospital accounting.-Examination report, Hospital Corps,

U.S. Navy; Form N. M. S. H. C. 1.-Analysis of the naval hospital ration for

1923 (continental hospitals only).-Reprints of the bureau's circular letters

for office files.-Additional data required on the Form F card in all cases of

injury.-Health records retained in files.-Wampoles hypno-bromic

compound.-Wampoles hypno-bromic compound, analysis requested_____________________

81</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">BOOK NOTICES---------------------------------------------------- 103</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREVENTIVE MEDICINE, STATISTICS:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PNEUMONIA, BRONCHITIS, AND TONSILLITIS SEASON. HOUSING, VENTILATION,

AND CONTACT.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. Commander J. R. Phelps, Medical Corps, U. S. Navy__ 107</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Mass immunity to diseases.-Human intestinal parasites in

Guam.Prevention of venereal disease in England.-Vital statistics_______ 127</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Number 2</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREFACE--------- - - - - --- --- - -- - ---- - -- - -- - ---- --------

---- - - -- -v</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTICE TO SERVICE CONTRIBUTORS --- -- -- -- -- - - ------ - -- - vi</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SPECIAL ARTICLE :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">DETECTION OF THE PSYCHOPATH AND CLASSIFICATION OF NAVAL RECRUITS</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">IN ACCORDANCE WITH THEIR INTELLIGENCE.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. A. W. Stearns, Medical Corps, United States Navy _<span>  </span>149</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">INSULIN TREATMENT OF DIABETES MELLITUS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. Commander W. D. Owens, Medical Corps, United States Navy __________________

_ 170</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOVOCAINE ANESTHESIA.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. Commander G. F. Cottle, Medical Corps, United States Navy

________________ 184</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">OBSERVATIONS CONCERNING YAWS IN HAITI.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. P. W. Wilson, Medical Corps, United States Navy _ _<span>  </span>190</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">RELATION OF THE CLINICAL LABORATORY TO THE MODERN HOSPITAL.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. H. S. Sumerlin, Medical Corps, United States Navy _<span>   </span>196</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">GAS MASK FOR HEAD AND CHEST INJURY CASES.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. F. F. Lane, Medical Corps, United States Navy_____ 200</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">CLINICAL NOTES:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">IMPROVED TECHNIC IN SPINAL PUNCTURE.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. Commander T. W. Raison, Medical Corps, United States Navy____________

205</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">TRAUMATIC HEMATOMA OF SPERMATIC CORD.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. L. H. Williams, Medical Corps, United States Navy__ 206</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">CYSTOSCOPY AND REPORT OF THREE UNUSUAL CASES.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. L. B. Marshall, Medical Corps, United States Navy__ 207</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTES AND COMMENTS:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Value of psychometric tests in the Navy-Need of physiotherapy – Two physicians

of Tortola-The all-purpose canister gas mask<span> 

</span>- Etiology of gout-Bulletin of the National Board of Medical Examiner</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">·-Practical objectives in health work-Alcohol taxation and alcoholism

in Denmark-Revision of the pharmacopaeia-Phlebotomy in the monasteries-New

method of treating syphilis-Operating-room lighting_____ ______ ____ ____ __

___ ____ __ ___ __ ___ ____ 213</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NURSE CORPS:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Nursing in the Philippine Islands-Cooperation with all departments_ 231</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">BOOK NOTICES __ _ 235</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREVENTIVE MEDICINE, STATISTICS:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">ERADICATION OF VERMIN ON BOARD SHIP_______________________ 247</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SPPLEMENTARY REPORT: REVIEW OF LITERATURE RELATING TO PROPHYLAXIS OF

MEASLES.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Dr. T. W. Kemmerer, United States Public Health Service__ 268</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SWIMMING POOLS IN DETROIT---EPIDEMIOLOGICAL CONSIDERATIONS__ 271</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">ADOPTION OF NEW HOUSING ORDINANCE BY THE CITY OF SAN DIEGO, CALIF_274</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">MEDICAL DEPARTMENT ACTIVITIES AT NAVAL TRAINING STATIONS__ 275</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Number 3</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREFACE ------------------------ v</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTICE TO SERVICE CONTRIBUTORS- VI</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SPECIAL ARTICLES:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">AVIATION ACCIDENTS AND METHODS OF PREVENTION.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. J. F. Neuberger, Medical Corps, U. S. Navy__________ 285</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTES AND COMMENTS :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Aviation accidents.-Aeroplane accidents from the British viewpoint.-

The estimation of physical efficiency.-The air ambulance in war.---Gas warfare

in the air.-Ophthalmology in its relation to</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">aviation.-Notes on aviation medicine in France.-Fellowship in the American

College of Surgeons.- Vaccination against smallpox -The instruction of hospital

corpsmen__ 331</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NAVY NURSE CORPS:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTES ON A COURSE FOR INSTRUCTORS OF NURSING-- 363</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREVENTIVE MEDICINE, STATISTICS:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">REMARKS ON THE EPIDEMIOLOGY OF SMALLPOX AND THE PREVENTIVE VALUE OF

VACCINATION WITH COWPOX VIRUS.- MEDICAL OFFICER RECOMMENDS ADOPTION OF A

REGISTER FOR COWPOX VACCINATIONS.- REPORT OF A CASE OF CEREBROSPINAL FEVER AT

THE UNITED STATES NAVAL TRAINING STATION, NEWPORT, R. I.-MEDICAL BULLETIN OF THE

DESTROYER SQUADRONS OF THE BATTLE FLEET.-PROPHYLAXIS OF VENEREAL

DISEASE.-BACILLARY DYSENTERY IN GUAM.-PORTABLE</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">CANVAS SACK STEAM DISINFECTORS AVAILABLE ___________ 395</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Number 4</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREFACE - --- ------ - - --- --- --------- - --- V</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTICE TO SERVICE CONTRIBUTORS__ _________ VI 1</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SPECIAL ARTICLES:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">ELECTROCARDIOGRAPH IN PROGNOSIS VALUE OF.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. Commander W. a. Bloedorn and Lieut. L . J. Roberts, Medical

Corps, United States Navy____ 423</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">ETHYLENE FOR GENERAL ANESTHESIA, USE OF.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander<span>  </span>C. W. Moots,

Medical Corps, United States Naval Reserve Force _ -----.- - - --------

------------- - - - ----------- 429</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">HYDRONEPHROSIS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. Commander R Cuthbertson, Medical Corps, United States Navy

------------ 431</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">UNSUSPECTED SYPHILIS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. Commander W. H. Connor, Medical Corps, United States

Navy_______ 439</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">RISE OF LOCAL ANESTHESIA.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Dr. Charles A. Ingraham ___________ ____________ ___________ 445</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">CLINICAL NOTES:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SARCOMA.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. R. M. Choisser, Medical Corps, United States Navy 451</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">AVULSION OF SCROTUM, LEFT TESTICAL AND SHEATH OF PENIS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. Commander G. F. Cottle, Medical Corps, United States Navy

-------------------------------- 457</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">HYDATIDIFORM MOLE, CASE OF.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. Commander C. C. Kress and Lieut. H. C. Bishop, jr., Medical

Corps, United States Navy____ 460</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTES AND COMMENTS:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Mental tests for recruits-Fish poisons-An eighteenth century country

practice-medical expedition to the South Seas-How to use a refrigerator-

Anaphylactic reaction from typhoid prophylaxis ------------- 463</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NAVY NURSE CORPS:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Relation of the dietetic department to the medical service of a </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">hospital_____________________________________________ 477</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">BOOK NOTICES -------------------------------- 483</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREVENTIVE MEDICINE. STATISTICS:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">The prevention and control of cerebrospinal fever in the British Army as

reviewed in the official history of the war ____________ 493</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Comments relating to health conditions, from the annual report of the

commander of the United States naval detachment in Turkish waters--Toxic effect

of hydrogen sulphide-Eradication of ants from ships of the United Fruit

Co.-Physical examination of food handlers in New York City- Venereal diseases

and prophylaxis in the United States Asiatic Fleet- Typhoid fever report-

Dysentery and the tendency to report ill-defined cases under a dysentery title

- Remarks relating- to the use of nomenclature titles____ _____ 515</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Number 5</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREFACE -- ------- ------------------------------------------------- v</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTICE TO SERVICE CONTRIBUTORS __________________________ _ vi</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SPECIAL ARTICLES : </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">MEDICAL DEPARTMENT OF THE MARINE CORPS, EAST COAST EXPEDITIONARY FORCE,

DURING THE FALL MANEUVERS OF 1923, AN ACCOUNTOF</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. Commander W. Chambers, Medical Corps, U. S. N.____ 531</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PYELOGRAPHY.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Commander W. S. Pugh, Medical Corps, U.S. N. (ret.)______ 559</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">HYDRONEPHROSIS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. (J. G.) R B. Engle. Medical Corps. U. S. N. 567</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">BICHLORIDE OF MERCURY POISONING WITH CALCIUM SULPHIDE AS A CHEMICAL

ANTIDOTE – A PRELIMINARY REPORT OF THE TREATMENT OF.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. J. M. McCants, Medical Corps, U. S. N. _______________ 572</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">CONSTRUCTION OF VULCANITE PARTIAL DENTURES.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. L. M. Desmond, Dental Corps, U. S. N.---------------- 578</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">CLINICAL NOTES:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">CHRONIC DUODENAL ULCER.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. (J. G.) O. A. Smith, Medical Corps, U. S. N. __________ 581</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">MALIGNANT ENDOCARDITIS FOLLOWING FRACTURE OF THE RIBS, A CARE REPORT.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. (J. G.) B. M. Summers, Medical Corps. U. S. N. ______ 586</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">INCONTINENCE OF URINE.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. (J. G) E. M. Harris, jr., Medical Corps, U. S. N. ______ 591</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">REPORT OF A DEATH OCCURING DURING TREATMENT FOR LEPROSY WITH

CHAULMOOGRA OIL DERIVATIVES.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. F. L. McDaniel, Medical Corps, U. S. N. ______________ 594</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTES AND COMMENTS:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">German hospital ship during the ·world War – Misconduct ruling__ 597</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NAVY NURSE CORPS:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Notes on dietetics taken at Miss Farmer's School of Cookery, Boston, Mass.

----------------- 605</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">INSTRUCTIONS ISSUED BY THE BUREAU OF MEDICINE AND SURGERY:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Patients suffering with tuberculosis or neuropsychiatric diseases and conditions

who are veterans of the Spanish-American War, Boxer Rebellion, and the

Philippine lnsurrection, now under treatment but who are not beneficiaries of

the Veterans' Bureau as veterans of the World War, and who are not at present

members of the regular military and naval establishments--Hospital Corps

Handbook. U.S. Navy, 1923, issue of-Adoption of revised Nomenclature of Diseases

and Injuries, Medical Department. U.S. Navy-Classified expenditures and per

diem cost in naval hospitals (continental), during the quarter ending September

30, 1923--Paragraphs 1280 and 1281, Naval Courts and Boards,

1923-Epidemiological study of influenza, the common cold and other respiratory

disorders, now being carried on by the U. S. Public Health Service, request for

cooperation by medical officers of the Navy-Influenza, the common cold, and

other respiratory disorders - Schedule of wages for civilian employees,

effective .January 1. 1924 -Laboratory courses for nurses of the U.S. Navy -

Enlistment of men not physically qualified - <span> </span>Administration of triple antityphoid

vaccine-Classified expenditures and per item cost in naval hospitals

(continental) during October, 1923 - Form F cards in cases of patients taken up

as from change of diagnosis - Form “ X " - Abstract of enlistments- Addition

of diagnostic title number 1973, “Urticaria," to</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Navy Nomenclature of Diseases and Injuries-Care in handling

concentrated spirit of nitrous ether- <span> </span>Equalization

bill - Modification of present allotment system-Instrument, plastic filling.

Black’s, Nos. 1 to 7, addition to Supply Table, Part II – Assignment of light

duty to hospital patients- Form N. M. S. H. C. S.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">forwarding of, in the case of hospital corpsmen whose records have been

closed fo1· desertion and convicted of absence without leave, or absence over

leave, 01· restored to duty-American Red Cross-Disciplinary regulations

referring to beneficiaries of the U. S. Veterans' Bureau in naval hospitals--Complement

fixation tests for syphilis-Transportation of Insane patients-Closer relation

between medical officers on recruiting duty and the Bureau of Medicine and

Surgery-Memorandum for medical officers on recruiting duty-. Applicants for

appointment in the Navy Nurse Corp, physical examination of--Change in the

Manual of the Medical Department - --- --------------- - ----- -------- ----- -

- - -- __ 617</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">BOOK NOTICES __ --------- - --- --- - ------ --- ---- ----- --- - -----

- - 653</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREVENTIVE MEDICINE STATISTICS:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Resuscitation apparatus - Follow-up treatment of syphilis- Accident statistics

injuries and poisonings-Methods used in the prevention and control of

communicable diseases at the naval training station, Hampton Roads, Va.-

Venereal disease experience of the U.S. S. Detroit during her

"shakedown" cruise—Typhoid fever report-Eradication of vermin : note

from the Marine Barracks, Washington, D. C.- Food poisoning- Improved sanitary quality

of foods now marketed compared with conditions ten years ago, as observed in

Detroit-Physiological effects of high temperatures and high relative

humidity-Supplementary report on tentative bacteriological standards for

swimming pools in Detroit-Correct reporting of cases remaining at the end of

the calendar year 1923 ---------------------- 659</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Number 6</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;"> </p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREFACE ________ v</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTICE TO SERYICE CONTRIBUTORS ----------------------------- vi</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SPECIAL ARTICLES:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">DIAGNOSIS OF EARLY PULMONARY TUBERCULOSIS</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. W. L. Rathbun, Medical Corps, U. S. Naval Reserve Force

____________ 685</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PULMONARY TUBERCULOSIS, EARLY DIAGNOSIS AND TREATMENT OF.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. Commander J. B. Pollard, Medical Corps, U. S. Navy_ 691</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">EXTENSIVE SUPERFICIAL BURNS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. Commander G. W. Shepard, ledical Corps, U. S. Navy_ 697</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">SULPHARSPHENAMINE, A REPORT ON ITS USE AT THE MAYO CLINIC, ROCHESTER.

MINN.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. Commander R. Hayden, Medical Corps, U. S. Navy.__ _<span>  </span>702</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">LEPROSY IN THE HAWAIIAN ISLANDS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. J. M. McCants, Medical Corps, U. S. Navy ________ _ 705</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">CLINICAL NOTES:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">KONDOLEON OPERATION AND FILARIASIS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. Commander H. M. Stenhouse. Medical Corps, U. S. Navy

____________ <span> </span>715</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">MAXILLARY SINUSITIS OF DENTAL ORIGIN.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. E. B. Howell, Dental Corps, U. S. Navy_____________ 716</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">REPORT OF A CASE OF LARGE "SOLITARY" TUBERCULOUS ABSCESS OF LIVER.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. L. F. Robinson. Medical Corps, U. S. Naval Reserve Force-------------------------------

719</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">ADVANCED TUBERCULOSIS UNSUCCESSFULLY TREATED BY ARTIFICIAL PNEUMOTHORAX,

COMPLICATED BY PYO-PNEUMOTHORAX AND TREATMENT BY THORACOPLASTY, A CASE OF.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. (Junior Grade) E. W. Gutzmer, Medical Corps, U. S. Navy

---------------------------------- 721</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NOTES AND COMMENTS :</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">A correction.-Value and limitations of the Rontgen ray in the diagnosis

of pulmonary affections. - Sulpharsphenamine on board ship.-A note on

interpretation of dental radiographs __________ - 727</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">NAVY NURSE CORPS:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">MY FIRST DUTY ABOARD SHIP. THE U. S. S.

"RELIEF"-------------- 739</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">BOOK NOTICES--------------------------------- 751</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">PREVENTIVE MEDICINE, STATISTICS:</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">STUDIES OF SUBMARINE VENTILATION IN TROPICAL WATERS.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. Commander R. F. Jones and Lieut. G. H. Mankin, Medical Corps,

U. S. Navy ----------- 759</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">STUDIES BY THE UNIITED STATES PUBLIC HEALTH SERVICE REGARDING CHEMICAL

AND PHYSIOLOGICAL ASPECTS OF INDUSTRIAL FATIGUE__ 795</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">EPIDEMIOLOGICAL REPORT OF AN OUTBREAK OF<span>  </span>BACILLARY DYSENTERY AT THE MARINE BARRACKS,

RIFLE RANGE, SANTO DOMINGO CITY, DOMINICAN REPUBLIC.</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">By Lieut. H. B. LaFavre, medical Corps, U. S. Navy____________ 797</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">Bacillary dysentery among Marine Corps and Nay personnel serving with

the gendarmerie of Haiti.- Bacillary dysentery in Guam. Needless noise a

detriment to health and efficiency.-Naval training stations, notes

from.-Venereal disease conditions from the U. S. S. "Pittsburgh,"

report on.-Fatal accident attributed to rusty surface of a revolving

shaft-Admissions for injuries and poisonings,</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">January and February, 1924------------------------- 800</p>

 

<p class="MsoNormal" style="margin-bottom:.0001pt;line-height:normal;">INDEX<span>  </span>…. I</p>

  

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I am living with Multiple Endocrine Neoplasia 2a. It's a rare genetic disorder that I was born with. It causes Medullary Thyroid Cancer, which has no cure, tumors of the adrenal glands and hyperparathyroidism. As tired as I get, I am a distance runner and use running to keep my mind and body healthy. I also run to raise money for research for my rare disease. I speak at events, educating people about the need for more research and treatment options for people like me. Every day is new and unique. Every day is rare! I try to live fully and completely on each one of those unique days.

Fish, any of approximately 34,000 species of vertebrate animals (phylum Chordata) found in the fresh and salt waters of the world. Living species range from the primitive jawless lampreys and hagfishes through the cartilaginous sharks, skates, and rays to the abundant and diverse bony fishes. Most fish species are cold-blooded; however, one species, the opah (Lampris guttatus), is warm-blooded.

 

The term fish is applied to a variety of vertebrates of several evolutionary lines. It describes a life-form rather than a taxonomic group. As members of the phylum Chordata, fish share certain features with other vertebrates. These features are gill slits at some point in the life cycle, a notochord, or skeletal supporting rod, a dorsal hollow nerve cord, and a tail. Living fishes represent some five classes, which are as distinct from one another as are the four classes of familiar air-breathing animals—amphibians, reptiles, birds, and mammals. For example, the jawless fishes (Agnatha) have gills in pouches and lack limb girdles. Extant agnathans are the lampreys and the hagfishes. As the name implies, the skeletons of fishes of the class Chondrichthyes (from chondr, “cartilage,” and ichthyes, “fish”) are made entirely of cartilage. Modern fish of this class lack a swim bladder, and their scales and teeth are made up of the same placoid material. Sharks, skates, and rays are examples of cartilaginous fishes. The bony fishes are by far the largest class. Examples range from the tiny seahorse to the 450-kg (1,000-pound) blue marlin, from the flattened soles and flounders to the boxy puffers and ocean sunfishes. Unlike the scales of the cartilaginous fishes, those of bony fishes, when present, grow throughout life and are made up of thin overlapping plates of bone. Bony fishes also have an operculum that covers the gill slits.

 

The study of fishes, the science of ichthyology, is of broad importance. Fishes are of interest to humans for many reasons, the most important being their relationship with and dependence on the environment. A more obvious reason for interest in fishes is their role as a moderate but important part of the world’s food supply. This resource, once thought unlimited, is now realized to be finite and in delicate balance with the biological, chemical, and physical factors of the aquatic environment. Overfishing, pollution, and alteration of the environment are the chief enemies of proper fisheries management, both in fresh waters and in the ocean. (For a detailed discussion of the technology and economics of fisheries, see commercial fishing.) Another practical reason for studying fishes is their use in disease control. As predators on mosquito larvae, they help curb malaria and other mosquito-borne diseases.

 

Fishes are valuable laboratory animals in many aspects of medical and biological research. For example, the readiness of many fishes to acclimate to captivity has allowed biologists to study behaviour, physiology, and even ecology under relatively natural conditions. Fishes have been especially important in the study of animal behaviour, where research on fishes has provided a broad base for the understanding of the more flexible behaviour of the higher vertebrates. The zebra fish is used as a model in studies of gene expression.

 

There are aesthetic and recreational reasons for an interest in fishes. Millions of people keep live fishes in home aquariums for the simple pleasure of observing the beauty and behaviour of animals otherwise unfamiliar to them. Aquarium fishes provide a personal challenge to many aquarists, allowing them to test their ability to keep a small section of the natural environment in their homes. Sportfishing is another way of enjoying the natural environment, also indulged in by millions of people every year. Interest in aquarium fishes and sportfishing supports multimillion-dollar industries throughout the world.

 

Fishes have been in existence for more than 450 million years, during which time they have evolved repeatedly to fit into almost every conceivable type of aquatic habitat. In a sense, land vertebrates are simply highly modified fishes: when fishes colonized the land habitat, they became tetrapod (four-legged) land vertebrates. The popular conception of a fish as a slippery, streamlined aquatic animal that possesses fins and breathes by gills applies to many fishes, but far more fishes deviate from that conception than conform to it. For example, the body is elongate in many forms and greatly shortened in others; the body is flattened in some (principally in bottom-dwelling fishes) and laterally compressed in many others; the fins may be elaborately extended, forming intricate shapes, or they may be reduced or even lost; and the positions of the mouth, eyes, nostrils, and gill openings vary widely. Air breathers have appeared in several evolutionary lines.

 

Many fishes are cryptically coloured and shaped, closely matching their respective environments; others are among the most brilliantly coloured of all organisms, with a wide range of hues, often of striking intensity, on a single individual. The brilliance of pigments may be enhanced by the surface structure of the fish, so that it almost seems to glow. A number of unrelated fishes have actual light-producing organs. Many fishes are able to alter their coloration—some for the purpose of camouflage, others for the enhancement of behavioral signals.

 

Fishes range in adult length from less than 10 mm (0.4 inch) to more than 20 metres (60 feet) and in weight from about 1.5 grams (less than 0.06 ounce) to many thousands of kilograms. Some live in shallow thermal springs at temperatures slightly above 42 °C (100 °F), others in cold Arctic seas a few degrees below 0 °C (32 °F) or in cold deep waters more than 4,000 metres (13,100 feet) beneath the ocean surface. The structural and, especially, the physiological adaptations for life at such extremes are relatively poorly known and provide the scientifically curious with great incentive for study.

 

Almost all natural bodies of water bear fish life, the exceptions being very hot thermal ponds and extremely salt-alkaline lakes, such as the Dead Sea in Asia and the Great Salt Lake in North America. The present distribution of fishes is a result of the geological history and development of Earth as well as the ability of fishes to undergo evolutionary change and to adapt to the available habitats. Fishes may be seen to be distributed according to habitat and according to geographical area. Major habitat differences are marine and freshwater. For the most part, the fishes in a marine habitat differ from those in a freshwater habitat, even in adjacent areas, but some, such as the salmon, migrate from one to the other. The freshwater habitats may be seen to be of many kinds. Fishes found in mountain torrents, Arctic lakes, tropical lakes, temperate streams, and tropical rivers will all differ from each other, both in obvious gross structure and in physiological attributes. Even in closely adjacent habitats where, for example, a tropical mountain torrent enters a lowland stream, the fish fauna will differ. The marine habitats can be divided into deep ocean floors (benthic), mid-water oceanic (bathypelagic), surface oceanic (pelagic), rocky coast, sandy coast, muddy shores, bays, estuaries, and others. Also, for example, rocky coastal shores in tropical and temperate regions will have different fish faunas, even when such habitats occur along the same coastline.

 

Although much is known about the present geographical distribution of fishes, far less is known about how that distribution came about. Many parts of the fish fauna of the fresh waters of North America and Eurasia are related and undoubtedly have a common origin. The faunas of Africa and South America are related, extremely old, and probably an expression of the drifting apart of the two continents. The fauna of southern Asia is related to that of Central Asia, and some of it appears to have entered Africa. The extremely large shore-fish faunas of the Indian and tropical Pacific oceans comprise a related complex, but the tropical shore fauna of the Atlantic, although containing Indo-Pacific components, is relatively limited and probably younger. The Arctic and Antarctic marine faunas are quite different from each other. The shore fauna of the North Pacific is quite distinct, and that of the North Atlantic more limited and probably younger. Pelagic oceanic fishes, especially those in deep waters, are similar the world over, showing little geographical isolation in terms of family groups. The deep oceanic habitat is very much the same throughout the world, but species differences do exist, showing geographical areas determined by oceanic currents and water masses.

 

All aspects of the life of a fish are closely correlated with adaptation to the total environment, physical, chemical, and biological. In studies, all the interdependent aspects of fish, such as behaviour, locomotion, reproduction, and physical and physiological characteristics, must be taken into account.

 

Correlated with their adaptation to an extremely wide variety of habitats is the extremely wide variety of life cycles that fishes display. The great majority hatch from relatively small eggs a few days to several weeks or more after the eggs are scattered in the water. Newly hatched young are still partially undeveloped and are called larvae until body structures such as fins, skeleton, and some organs are fully formed. Larval life is often very short, usually less than a few weeks, but it can be very long, some lampreys continuing as larvae for at least five years. Young and larval fishes, before reaching sexual maturity, must grow considerably, and their small size and other factors often dictate that they live in a habitat different than that of the adults. For example, most tropical marine shore fishes have pelagic larvae. Larval food also is different, and larval fishes often live in shallow waters, where they may be less exposed to predators.

 

After a fish reaches adult size, the length of its life is subject to many factors, such as innate rates of aging, predation pressure, and the nature of the local climate. The longevity of a species in the protected environment of an aquarium may have nothing to do with how long members of that species live in the wild. Many small fishes live only one to three years at the most. In some species, however, individuals may live as long as 10 or 20 or even 100 years.

 

Fish behaviour is a complicated and varied subject. As in almost all animals with a central nervous system, the nature of a response of an individual fish to stimuli from its environment depends upon the inherited characteristics of its nervous system, on what it has learned from past experience, and on the nature of the stimuli. Compared with the variety of human responses, however, that of a fish is stereotyped, not subject to much modification by “thought” or learning, and investigators must guard against anthropomorphic interpretations of fish behaviour.

 

Fishes perceive the world around them by the usual senses of sight, smell, hearing, touch, and taste and by special lateral line water-current detectors. In the few fishes that generate electric fields, a process that might best be called electrolocation aids in perception. One or another of these senses often is emphasized at the expense of others, depending upon the fish’s other adaptations. In fishes with large eyes, the sense of smell may be reduced; others, with small eyes, hunt and feed primarily by smell (such as some eels).

 

Specialized behaviour is primarily concerned with the three most important activities in the fish’s life: feeding, reproduction, and escape from enemies. Schooling behaviour of sardines on the high seas, for instance, is largely a protective device to avoid enemies, but it is also associated with and modified by their breeding and feeding requirements. Predatory fishes are often solitary, lying in wait to dart suddenly after their prey, a kind of locomotion impossible for beaked parrot fishes, which feed on coral, swimming in small groups from one coral head to the next. In addition, some predatory fishes that inhabit pelagic environments, such as tunas, often school.

 

Sleep in fishes, all of which lack true eyelids, consists of a seemingly listless state in which the fish maintains its balance but moves slowly. If attacked or disturbed, most can dart away. A few kinds of fishes lie on the bottom to sleep. Most catfishes, some loaches, and some eels and electric fishes are strictly nocturnal, being active and hunting for food during the night and retiring during the day to holes, thick vegetation, or other protective parts of the environment.

 

Communication between members of a species or between members of two or more species often is extremely important, especially in breeding behaviour (see below Reproduction). The mode of communication may be visual, as between the small so-called cleaner fish and a large fish of a very different species. The larger fish often allows the cleaner to enter its mouth to remove gill parasites. The cleaner is recognized by its distinctive colour and actions and therefore is not eaten, even if the larger fish is normally a predator. Communication is often chemical, signals being sent by specific chemicals called pheromones.

 

Many fishes have a streamlined body and swim freely in open water. Fish locomotion is closely correlated with habitat and ecological niche (the general position of the animal to its environment).

 

Many fishes in both marine and fresh waters swim at the surface and have mouths adapted to feed best (and sometimes only) at the surface. Often such fishes are long and slender, able to dart at surface insects or at other surface fishes and in turn to dart away from predators; needlefishes, halfbeaks, and topminnows (such as killifish and mosquito fish) are good examples. Oceanic flying fishes escape their predators by gathering speed above the water surface, with the lower lobe of the tail providing thrust in the water. They then glide hundreds of yards on enlarged, winglike pectoral and pelvic fins. South American freshwater flying fishes escape their enemies by jumping and propelling their strongly keeled bodies out of the water.

 

So-called mid-water swimmers, the most common type of fish, are of many kinds and live in many habitats. The powerful fusiform tunas and the trouts, for example, are adapted for strong, fast swimming, the tunas to capture prey speedily in the open ocean and the trouts to cope with the swift currents of streams and rivers. The trout body form is well adapted to many habitats. Fishes that live in relatively quiet waters such as bays or lake shores or slow rivers usually are not strong, fast swimmers but are capable of short, quick bursts of speed to escape a predator. Many of these fishes have their sides flattened, examples being the sunfish and the freshwater angelfish of aquarists. Fish associated with the bottom or substrate usually are slow swimmers. Open-water plankton-feeding fishes almost always remain fusiform and are capable of rapid, strong movement (for example, sardines and herrings of the open ocean and also many small minnows of streams and lakes).

 

Bottom-living fishes are of many kinds and have undergone many types of modification of their body shape and swimming habits. Rays, which evolved from strong-swimming mid-water sharks, usually stay close to the bottom and move by undulating their large pectoral fins. Flounders live in a similar habitat and move over the bottom by undulating the entire body. Many bottom fishes dart from place to place, resting on the bottom between movements, a motion common in gobies. One goby relative, the mudskipper, has taken to living at the edge of pools along the shore of muddy mangrove swamps. It escapes its enemies by flipping rapidly over the mud, out of the water. Some catfishes, synbranchid eels, the so-called climbing perch, and a few other fishes venture out over damp ground to find more promising waters than those that they left. They move by wriggling their bodies, sometimes using strong pectoral fins; most have accessory air-breathing organs. Many bottom-dwelling fishes live in mud holes or rocky crevices. Marine eels and gobies commonly are found in such habitats and for the most part venture far beyond their cavelike homes. Some bottom dwellers, such as the clingfishes (Gobiesocidae), have developed powerful adhesive disks that enable them to remain in place on the substrate in areas such as rocky coasts, where the action of the waves is great.

 

The methods of reproduction in fishes are varied, but most fishes lay a large number of small eggs, fertilized and scattered outside of the body. The eggs of pelagic fishes usually remain suspended in the open water. Many shore and freshwater fishes lay eggs on the bottom or among plants. Some have adhesive eggs. The mortality of the young and especially of the eggs is very high, and often only a few individuals grow to maturity out of hundreds, thousands, and in some cases millions of eggs laid.

 

Males produce sperm, usually as a milky white substance called milt, in two (sometimes one) testes within the body cavity. In bony fishes a sperm duct leads from each testis to a urogenital opening behind the vent or anus. In sharks and rays and in cyclostomes the duct leads to a cloaca. Sometimes the pelvic fins are modified to help transmit the milt to the eggs at the female’s vent or on the substrate where the female has placed them. Sometimes accessory organs are used to fertilize females internally—for example, the claspers of many sharks and rays.

 

In the females the eggs are formed in two ovaries (sometimes only one) and pass through the ovaries to the urogenital opening and to the outside. In some fishes the eggs are fertilized internally but are shed before development takes place. Members of about a dozen families each of bony fishes (teleosts) and sharks bear live young. Many skates and rays also bear live young. In some bony fishes the eggs simply develop within the female, the young emerging when the eggs hatch (ovoviviparous). Others develop within the ovary and are nourished by ovarian tissues after hatching (viviparous). There are also other methods utilized by fishes to nourish young within the female. In all live-bearers the young are born at a relatively large size and are few in number. In one family of primarily marine fishes, the surfperches from the Pacific coast of North America, Japan, and Korea, the males of at least one species are born sexually mature, although they are not fully grown.

 

Some fishes are hermaphroditic—an individual producing both sperm and eggs, usually at different stages of its life. Self-fertilization, however, is probably rare.

 

Successful reproduction and, in many cases, defense of the eggs and the young are assured by rather stereotypical but often elaborate courtship and parental behaviour, either by the male or the female or both. Some fishes prepare nests by hollowing out depressions in the sand bottom (cichlids, for example), build nests with plant materials and sticky threads excreted by the kidneys (sticklebacks), or blow a cluster of mucus-covered bubbles at the water surface (gouramis). The eggs are laid in these structures. Some varieties of cichlids and catfishes incubate eggs in their mouths.

 

Some fishes, such as salmon, undergo long migrations from the ocean and up large rivers to spawn in the gravel beds where they themselves hatched (anadromous fishes). Some, such as the freshwater eels (family Anguillidae), live and grow to maturity in fresh water and migrate to the sea to spawn (catadromous fishes). Other fishes undertake shorter migrations from lakes into streams, within the ocean, or enter spawning habitats that they do not ordinarily occupy in other ways.

 

The basic structure and function of the fish body are similar to those of all other vertebrates. The usual four types of tissues are present: surface or epithelial, connective (bone, cartilage, and fibrous tissues, as well as their derivative, blood), nerve, and muscle tissues. In addition, the fish’s organs and organ systems parallel those of other vertebrates.

 

The typical fish body is streamlined and spindle-shaped, with an anterior head, a gill apparatus, and a heart, the latter lying in the midline just below the gill chamber. The body cavity, containing the vital organs, is situated behind the head in the lower anterior part of the body. The anus usually marks the posterior termination of the body cavity and most often occurs just in front of the base of the anal fin. The spinal cord and vertebral column continue from the posterior part of the head to the base of the tail fin, passing dorsal to the body cavity and through the caudal (tail) region behind the body cavity. Most of the body is of muscular tissue, a high proportion of which is necessitated by swimming. In the course of evolution this basic body plan has been modified repeatedly into the many varieties of fish shapes that exist today.

 

The skeleton forms an integral part of the fish’s locomotion system, as well as serving to protect vital parts. The internal skeleton consists of the skull bones (except for the roofing bones of the head, which are really part of the external skeleton), the vertebral column, and the fin supports (fin rays). The fin supports are derived from the external skeleton but will be treated here because of their close functional relationship to the internal skeleton. The internal skeleton of cyclostomes, sharks, and rays is of cartilage; that of many fossil groups and some primitive living fishes is mostly of cartilage but may include some bone. In place of the vertebral column, the earliest vertebrates had a fully developed notochord, a flexible stiff rod of viscous cells surrounded by a strong fibrous sheath. During the evolution of modern fishes the rod was replaced in part by cartilage and then by ossified cartilage. Sharks and rays retain a cartilaginous vertebral column; bony fishes have spool-shaped vertebrae that in the more primitive living forms only partially replace the notochord. The skull, including the gill arches and jaws of bony fishes, is fully, or at least partially, ossified. That of sharks and rays remains cartilaginous, at times partially replaced by calcium deposits but never by true bone.

 

The supportive elements of the fins (basal or radial bones or both) have changed greatly during fish evolution. Some of these changes are described in the section below (Evolution and paleontology). Most fishes possess a single dorsal fin on the midline of the back. Many have two and a few have three dorsal fins. The other fins are the single tail and anal fins and paired pelvic and pectoral fins. A small fin, the adipose fin, with hairlike fin rays, occurs in many of the relatively primitive teleosts (such as trout) on the back near the base of the caudal fin.

 

The skin of a fish must serve many functions. It aids in maintaining the osmotic balance, provides physical protection for the body, is the site of coloration, contains sensory receptors, and, in some fishes, functions in respiration. Mucous glands, which aid in maintaining the water balance and offer protection from bacteria, are extremely numerous in fish skin, especially in cyclostomes and teleosts. Since mucous glands are present in the modern lampreys, it is reasonable to assume that they were present in primitive fishes, such as the ancient Silurian and Devonian agnathans. Protection from abrasion and predation is another function of the fish skin, and dermal (skin) bone arose early in fish evolution in response to this need. It is thought that bone first evolved in skin and only later invaded the cartilaginous areas of the fish’s body, to provide additional support and protection. There is some argument as to which came first, cartilage or bone, and fossil evidence does not settle the question. In any event, dermal bone has played an important part in fish evolution and has different characteristics in different groups of fishes. Several groups are characterized at least in part by the kind of bony scales they possess.

 

Scales have played an important part in the evolution of fishes. Primitive fishes usually had thick bony plates or thick scales in several layers of bone, enamel, and related substances. Modern teleost fishes have scales of bone, which, while still protective, allow much more freedom of motion in the body. A few modern teleosts (some catfishes, sticklebacks, and others) have secondarily acquired bony plates in the skin. Modern and early sharks possessed placoid scales, a relatively primitive type of scale with a toothlike structure, consisting of an outside layer of enamel-like substance (vitrodentine), an inner layer of dentine, and a pulp cavity containing nerves and blood vessels. Primitive bony fishes had thick scales of either the ganoid or the cosmoid type. Cosmoid scales have a hard, enamel-like outer layer, an inner layer of cosmine (a form of dentine), and then a layer of vascular bone (isopedine). In ganoid scales the hard outer layer is different chemically and is called ganoin. Under this is a cosminelike layer and then a vascular bony layer. The thin, translucent bony scales of modern fishes, called cycloid and ctenoid (the latter distinguished by serrations at the edges), lack enameloid and dentine layers.

 

Skin has several other functions in fishes. It is well supplied with nerve endings and presumably receives tactile, thermal, and pain stimuli. Skin is also well supplied with blood vessels. Some fishes breathe in part through the skin, by the exchange of oxygen and carbon dioxide between the surrounding water and numerous small blood vessels near the skin surface.

 

Skin serves as protection through the control of coloration. Fishes exhibit an almost limitless range of colours. The colours often blend closely with the surroundings, effectively hiding the animal. Many fishes use bright colours for territorial advertisement or as recognition marks for other members of their own species, or sometimes for members of other species. Many fishes can change their colour to a greater or lesser degree, by movement of pigment within the pigment cells (chromatophores). Black pigment cells (melanophores), of almost universal occurrence in fishes, are often juxtaposed with other pigment cells. When placed beneath iridocytes or leucophores (bearing the silvery or white pigment guanine), melanophores produce structural colours of blue and green. These colours are often extremely intense, because they are formed by refraction of light through the needlelike crystals of guanine. The blue and green refracted colours are often relatively pure, lacking the red and yellow rays, which have been absorbed by the black pigment (melanin) of the melanophores. Yellow, orange, and red colours are produced by erythrophores, cells containing the appropriate carotenoid pigments. Other colours are produced by combinations of melanophores, erythrophores, and iridocytes.

 

The major portion of the body of most fishes consists of muscles. Most of the mass is trunk musculature, the fin muscles usually being relatively small. The caudal fin is usually the most powerful fin, being moved by the trunk musculature. The body musculature is usually arranged in rows of chevron-shaped segments on each side. Contractions of these segments, each attached to adjacent vertebrae and vertebral processes, bends the body on the vertebral joint, producing successive undulations of the body, passing from the head to the tail, and producing driving strokes of the tail. It is the latter that provides the strong forward movement for most fishes.

 

The digestive system, in a functional sense, starts at the mouth, with the teeth used to capture prey or collect plant foods. Mouth shape and tooth structure vary greatly in fishes, depending on the kind of food normally eaten. Most fishes are predacious, feeding on small invertebrates or other fishes and have simple conical teeth on the jaws, on at least some of the bones of the roof of the mouth, and on special gill arch structures just in front of the esophagus. The latter are throat teeth. Most predacious fishes swallow their prey whole, and the teeth are used for grasping and holding prey, for orienting prey to be swallowed (head first) and for working the prey toward the esophagus. There are a variety of tooth types in fishes. Some fishes, such as sharks and piranhas, have cutting teeth for biting chunks out of their victims. A shark’s tooth, although superficially like that of a piranha, appears in many respects to be a modified scale, while that of the piranha is like that of other bony fishes, consisting of dentine and enamel. Parrot fishes have beaklike mouths with short incisor-like teeth for breaking off coral and have heavy pavementlike throat teeth for crushing the coral. Some catfishes have small brushlike teeth, arranged in rows on the jaws, for scraping plant and animal growth from rocks. Many fishes (such as the Cyprinidae or minnows) have no jaw teeth at all but have very strong throat teeth.

 

Some fishes gather planktonic food by straining it from their gill cavities with numerous elongate stiff rods (gill rakers) anchored by one end to the gill bars. The food collected on these rods is passed to the throat, where it is swallowed. Most fishes have only short gill rakers that help keep food particles from escaping out the mouth cavity into the gill chamber.

 

Once reaching the throat, food enters a short, often greatly distensible esophagus, a simple tube with a muscular wall leading into a stomach. The stomach varies greatly in fishes, depending upon the diet. In most predacious fishes it is a simple straight or curved tube or pouch with a muscular wall and a glandular lining. Food is largely digested there and leaves the stomach in liquid form.

 

Between the stomach and the intestine, ducts enter the digestive tube from the liver and pancreas. The liver is a large, clearly defined organ. The pancreas may be embedded in it, diffused through it, or broken into small parts spread along some of the intestine. The junction between the stomach and the intestine is marked by a muscular valve. Pyloric ceca (blind sacs) occur in some fishes at this junction and have a digestive or absorptive function or both.

 

The intestine itself is quite variable in length, depending upon the fish’s diet. It is short in predacious forms, sometimes no longer than the body cavity, but long in herbivorous forms, being coiled and several times longer than the entire length of the fish in some species of South American catfishes. The intestine is primarily an organ for absorbing nutrients into the bloodstream. The larger its internal surface, the greater its absorptive efficiency, and a spiral valve is one method of increasing its absorption surface.

 

Sharks, rays, chimaeras, lungfishes, surviving chondrosteans, holosteans, and even a few of the more primitive teleosts have a spiral valve or at least traces of it in the intestine. Most modern teleosts have increased the area of the intestinal walls by having numerous folds and villi (fingerlike projections) somewhat like those in humans. Undigested substances are passed to the exterior through the anus in most teleost fishes. In lungfishes, sharks, and rays, it is first passed through the cloaca, a common cavity receiving the intestinal opening and the ducts from the urogenital system.

 

Oxygen and carbon dioxide dissolve in water, and most fishes exchange dissolved oxygen and carbon dioxide in water by means of the gills. The gills lie behind and to the side of the mouth cavity and consist of fleshy filaments supported by the gill arches and filled with blood vessels, which give gills a bright red colour. Water taken in continuously through the mouth passes backward between the gill bars and over the gill filaments, where the exchange of gases takes place. The gills are protected by a gill cover in teleosts and many other fishes but by flaps of skin in sharks, rays, and some of the older fossil fish groups. The blood capillaries in the gill filaments are close to the gill surface to take up oxygen from the water and to give up excess carbon dioxide to the water.

 

Most modern fishes have a hydrostatic (ballast) organ, called the swim bladder, that lies in the body cavity just below the kidney and above the stomach and intestine. It originated as a diverticulum of the digestive canal. In advanced teleosts, especially the acanthopterygians, the bladder has lost its connection with the digestive tract, a condition called physoclistic. The connection has been retained (physostomous) by many relatively primitive teleosts. In several unrelated lines of fishes, the bladder has become specialized as a lung or, at least, as a highly vascularized accessory breathing organ. Some fishes with such accessory organs are obligate air breathers and will drown if denied access to the surface, even in well-oxygenated water. Fishes with a hydrostatic form of swim bladder can control their depth by regulating the amount of gas in the bladder. The gas, mostly oxygen, is secreted into the bladder by special glands, rendering the fish more buoyant; the gas is absorbed into the bloodstream by another special organ, reducing the overall buoyancy and allowing the fish to sink. Some deep-sea fishes may have oils, rather than gas, in the bladder. Other deep-sea and some bottom-living forms have much-reduced swim bladders or have lost the organ entirely.

 

The swim bladder of fishes follows the same developmental pattern as the lungs of land vertebrates. There is no doubt that the two structures have the same historical origin in primitive fishes. More or less intermediate forms still survive among the more primitive types of fishes, such as the lungfishes Lepidosiren and Protopterus.

 

The circulatory, or blood vascular, system consists of the heart, the arteries, the capillaries, and the veins. It is in the capillaries that the interchange of oxygen, carbon dioxide, nutrients, and other substances such as hormones and waste products takes place. The capillaries lead to the veins, which return the venous blood with its waste products to the heart, kidneys, and gills. There are two kinds of capillary beds: those in the gills and those in the rest of the body. The heart, a folded continuous muscular tube with three or four saclike enlargements, undergoes rhythmic contractions and receives venous blood in a sinus venosus. It passes the blood to an auricle and then into a thick muscular pump, the ventricle. From the ventricle the blood goes to a bulbous structure at the base of a ventral aorta just below the gills. The blood passes to the afferent (receiving) arteries of the gill arches and then to the gill capillaries. There waste gases are given off to the environment, and oxygen is absorbed. The oxygenated blood enters efferent (exuant) arteries of the gill arches and then flows into the dorsal aorta. From there blood is distributed to the tissues and organs of the body. One-way valves prevent backflow. The circulation of fishes thus differs from that of the reptiles, birds, and mammals in that oxygenated blood is not returned to the heart prior to distribution to the other parts of the body.

 

The primary excretory organ in fishes, as in other vertebrates, is the kidney. In fishes some excretion also takes place in the digestive tract, skin, and especially the gills (where ammonia is given off). Compared with land vertebrates, fishes have a special problem in maintaining their internal environment at a constant concentration of water and dissolved substances, such as salts. Proper balance of the internal environment (homeostasis) of a fish is in a great part maintained by the excretory system, especially the kidney.

 

The kidney, gills, and skin play an important role in maintaining a fish’s internal environment and checking the effects of osmosis. Marine fishes live in an environment in which the water around them has a greater concentration of salts than they can have inside their body and still maintain life. Freshwater fishes, on the other hand, live in water with a much lower concentration of salts than they require inside their bodies. Osmosis tends to promote the loss of water from the body of a marine fish and absorption of water by that of a freshwater fish. Mucus in the skin tends to slow the process but is not a sufficient barrier to prevent the movement of fluids through the permeable skin. When solutions on two sides of a permeable membrane have different concentrations of dissolved substances, water will pass through the membrane into the more concentrated solution, while the dissolved chemicals move into the area of lower concentration (diffusion).

 

The kidney of freshwater fishes is often larger in relation to body weight than that of marine fishes. In both groups the kidney excretes wastes from the body, but the kidney of freshwater fishes also excretes large amounts of water, counteracting the water absorbed through the skin. Freshwater fishes tend to lose salt to the environment and must replace it. They get some salt from their food, but the gills and skin inside the mouth actively absorb salt from water passed through the mouth. This absorption is performed by special cells capable of moving salts against the diffusion gradient. Freshwater fishes drink very little water and take in little water with their food.

 

Marine fishes must conserve water, and therefore their kidneys excrete little water. To maintain their water balance, marine fishes drink large quantities of seawater, retaining most of the water and excreting the salt. Most nitrogenous waste in marine fishes appears to be secreted by the gills as ammonia. Marine fishes can excrete salt by clusters of special cells (chloride cells) in the gills.

 

There are several teleosts—for example, the salmon—that travel between fresh water and seawater and must adjust to the reversal of osmotic gradients. They adjust their physiological processes by spending time (often surprisingly little time) in the intermediate brackish environment.

 

Marine hagfishes, sharks, and rays have osmotic concentrations in their blood about equal to that of seawater and so do not have to drink water nor perform much physiological work to maintain their osmotic balance. In sharks and rays the osmotic concentration is kept high by retention of urea in the blood. Freshwater sharks have a lowered concentration of urea in the blood.

 

Endocrine glands secrete their products into the bloodstream and body tissues and, along with the central nervous system, control and regulate many kinds of body functions. Cyclostomes have a well-developed endocrine system, and presumably it was well developed in the early Agnatha, ancestral to modern fishes. Although the endocrine system in fishes is similar to that of higher vertebrates, there are numerous differences in detail. The pituitary, the thyroid, the suprarenals, the adrenals, the pancreatic islets, the sex glands (ovaries and testes), the inner wall of the intestine, and the bodies of the ultimobranchial gland make up the endocrine system in fishes. There are some others whose function is not well understood. These organs regulate sexual activity and reproduction, growth, osmotic pressure, general metabolic activities such as the storage of fat and the utilization of foodstuffs, blood pressure, and certain aspects of skin colour. Many of these activities are also controlled in part by the central nervous system, which works with the endocrine system in maintaining the life of a fish. Some parts of the endocrine system are developmentally, and undoubtedly evolutionarily, derived from the nervous system.

 

As in all vertebrates, the nervous system of fishes is the primary mechanism coordinating body activities, as well as integrating these activities in the appropriate manner with stimuli from the environment. The central nervous system, consisting of the brain and spinal cord, is the primary integrating mechanism. The peripheral nervous system, consisting of nerves that connect the brain and spinal cord to various body organs, carries sensory information from special receptor organs such as the eyes, internal ears, nares (sense of smell), taste glands, and others to the integrating centres of the brain and spinal cord. The peripheral nervous system also carries information via different nerve cells from the integrating centres of the brain and spinal cord. This coded information is carried to the various organs and body systems, such as the skeletal muscular system, for appropriate action in response to the original external or internal stimulus. Another branch of the nervous system, the autonomic nervous system, helps to coordinate the activities of many glands and organs and is itself closely connected to the integrating centres of the brain.

 

The brain of the fish is divided into several anatomical and functional parts, all closely interconnected but each serving as the primary centre of integrating particular kinds of responses and activities. Several of these centres or parts are primarily associated with one type of sensory perception, such as sight, hearing, or smell (olfaction).

 

The sense of smell is important in almost all fishes. Certain eels with tiny eyes depend mostly on smell for location of food. The olfactory, or nasal, organ of fishes is located on the dorsal surface of the snout. The lining of the nasal organ has special sensory cells that perceive chemicals dissolved in the water, such as substances from food material, and send sensory information to the brain by way of the first cranial nerve. Odour also serves as an alarm system. Many fishes, especially various species of freshwater minnows, react with alarm to a chemical released from the skin of an injured member of their own species.

 

Many fishes have a well-developed sense of taste, and tiny pitlike taste buds or organs are located not only within their mouth cavities but also over their heads and parts of their body. Catfishes, which often have poor vision, have barbels (“whiskers”) that serve as supplementary taste organs, those around the mouth being actively used to search out food on the bottom. Some species of naturally blind cave fishes are especially well supplied with taste buds, which often cover most of their body surface.

 

Sight is extremely important in most fishes. The eye of a fish is basically like that of all other vertebrates, but the eyes of fishes are extremely varied in structure and adaptation. In general, fishes living in dark and dim water habitats have large eyes, unless they have specialized in some compensatory way so that another sense (such as smell) is dominant, in which case the eyes will often be reduced. Fishes living in brightly lighted shallow waters often will have relatively small but efficient eyes. Cyclostomes have somewhat less elaborate eyes than other fishes, with skin stretched over the eyeball perhaps making their vision somewhat less effective. Most fishes have a spherical lens and accommodate their vision to far or near subjects by moving the lens within the eyeball. A few sharks accommodate by changing the shape of the lens, as in land vertebrates. Those fishes that are heavily dependent upon the eyes have especially strong muscles for accommodation. Most fishes see well, despite the restrictions imposed by frequent turbidity of the water and by light refraction.

 

Fossil evidence suggests that colour vision evolved in fishes more than 300 million years ago, but not all living fishes have retained this ability. Experimental evidence indicates that many shallow-water fishes, if not all, have colour vision and see some colours especially well, but some bottom-dwelling shore fishes live in areas where the water is sufficiently deep to filter out most if not all colours, and these fishes apparently never see colours. When tested in shallow water, they apparently are unable to respond to colour differences.

 

Sound perception and balance are intimately associated senses in a fish. The organs of hearing are entirely internal, located within the skull, on each side of the brain and somewhat behind the eyes. Sound waves, especially those of low frequencies, travel readily through water and impinge directly upon the bones and fluids of the head and body, to be transmitted to the hearing organs. Fishes readily respond to sound; for example, a trout conditioned to escape by the approach of fishermen will take flight upon perceiving footsteps on a stream bank even if it cannot see a fisherman. Compared with humans, however, the range of sound frequencies heard by fishes is greatly restricted. Many fishes communicate with each other by producing sounds in their swim bladders, in their throats by rasping their teeth, and in other ways.

 

A fish or other vertebrate seldom has to rely on a single type of sensory information to determine the nature of the environment around it. A catfish uses taste and touch when examining a food object with its oral barbels. Like most other animals, fishes have many touch receptors over their body surface. Pain and temperature receptors also are present in fishes and presumably produce the same kind of information to a fish as to humans. Fishes react in a negative fashion to stimuli that would be painful to human beings, suggesting that they feel a sensation of pain.

 

An important sensory system in fishes that is absent in other vertebrates (except some amphibians) is the lateral line system. This consists of a series of heavily innervated small canals located in the skin and bone around the eyes, along the lower jaw, over the head, and down the mid-side of the body, where it is associated with the scales. Intermittently along these canals are located tiny sensory organs (pit organs) that apparently detect changes in pressure. The system allows a fish to sense changes in water currents and pressure, thereby helping the fish to orient itself to the various changes that occur in the physical environment.

  

  

Navajo Technical University (NTU) was awarded $220,000 for 24 months, in 2018, under the U.S. Department of Agriculture (USDA) National Institute of Food and Agriculture (NIFA) Tribal College Research Grant Program, for the Fabrication and Education of Multi-Purpose Nano Electrochemical Sensor to Detect Endocrine Disruptors (Bisphenol Compounds) and Glucose in Navajo Nation project, that is led by NTU Chemistry Associate Professor Dr. Thiagarajan Soundappan, in Crownpoint, NM, on Sept. 9, 2019. Bisphenol also known as BPA can be found items such as receipts from thermal printers, and certain plastic bottles and containers. The research funding provides equipment and staff for the Electrochemical Research wet-laboratory in this one-year old facility.

  

Robinson Tom (Navajo) (SEEN) and Michael Nelwood are making BPA bio sensors that detect both BPA and glucose without the use of a needle or blood sample. The higher number of diabetes and high use of plastic containers in the Navajo Nation is a clear need for this type of sensor. The lack of nutritional and varied food sources on the reservation (food desert) lowers the community’s immune defense, making them vulnerable to diseases caused attributed to BPA contact and high glucose.

  

Tom also has experience with radon detection research for USDA, and DoD research developing more efficient battlefield batteries for U.S. servicemen. On a personal side, he has family members who are dealing with diabetes, so his motivation to develop the BPA/glucose sensors are close to him. Nellwood will take over research operations when Tom graduates next semester. Not only will the research be turned over, the will carry on with the in-demand community awareness sessions that teach the tribal community about the health concerns.

 

Both are U.S. Army veterans.

  

NTU was initially established in 1979 as the Navajo Skill Center and is the Navajo Nation’s first university. A highly respected land-grant institution, NTU offers technical, vocational, and academic degrees, as well as community education, in a student-oriented, hands-on learning environment with state-of-the-art classroom equipment.

  

In 1994, 29 tribal colleges received land-grant university (LGU) status, giving them access to federal government resources that would improve the lives of Native students through higher education and help propel American Indians toward self-sufficiency. These resources also support innovative research, education, and extension programs that positively impact agriculture and food production. The 1994 Land-Grants often serve as the primary institution of scientific inquiry, knowledge and learning for reservation communities.

 

USDA Photo by Lance Cheung, with permission from NTU.

  

For more information, please see:

 

nifa.usda.gov/program/tribal-college-research-grant-program

 

nifa.usda.gov/resource/first-20-years-1994-land-grant-institutions

  

Navajo Technical University (NTU) was awarded $220,000 for 24 months, in 2018, under the U.S. Department of Agriculture (USDA) National Institute of Food and Agriculture (NIFA) Tribal College Research Grant Program, for the Fabrication and Education of Multi-Purpose Nano Electrochemical Sensor to Detect Endocrine Disruptors (Bisphenol Compounds) and Glucose in Navajo Nation project, that is led by NTU Chemistry Associate Professor Dr. Thiagarajan Soundappan, in Crownpoint, NM, on Sept. 9, 2019. Bisphenol also known as BPA can be found items such as receipts from thermal printers, and certain plastic bottles and containers. The research funding provides equipment and staff for the Electrochemical Research wet-laboratory in this one-year old facility.

  

Robinson Tom (Navajo) and Michael Nelwood (SEEN) are making BPA bio sensors that detect both BPA and glucose without the use of a needle or blood sample. The higher number of diabetes and high use of plastic containers in the Navajo Nation is a clear need for this type of sensor. The lack of nutritional and varied food sources on the reservation (food desert) lowers the community’s immune defense, making them vulnerable to diseases caused attributed to BPA contact and high glucose.

  

Tom also has experience with radon detection research for USDA, and DoD research developing more efficient battlefield batteries for U.S. servicemen. On a personal side, he has family members who are dealing with diabetes, so his motivation to develop the BPA/glucose sensors are close to him. Nellwood will take over research operations when Tom graduates next semester. Not only will the research be turned over, the will carry on with the in-demand community awareness sessions that teach the tribal community about the health concerns.

 

Both are U.S. Army veterans.

  

NTU was initially established in 1979 as the Navajo Skill Center and is the Navajo Nation’s first university. A highly respected land-grant institution, NTU offers technical, vocational, and academic degrees, as well as community education, in a student-oriented, hands-on learning environment with state-of-the-art classroom equipment.

  

In 1994, 29 tribal colleges received land-grant university (LGU) status, giving them access to federal government resources that would improve the lives of Native students through higher education and help propel American Indians toward self-sufficiency. These resources also support innovative research, education, and extension programs that positively impact agriculture and food production. The 1994 Land-Grants often serve as the primary institution of scientific inquiry, knowledge and learning for reservation communities.

 

USDA Photo by Lance Cheung, with permission from NTU.

  

For more information, please see:

 

nifa.usda.gov/program/tribal-college-research-grant-program

 

nifa.usda.gov/resource/first-20-years-1994-land-grant-institutions