z en ° nn P m ii- (.") - — O en > ■ ■ r- 1 — CO /^ \^i* 4v Qnnivnw ^/ ' common in mammals. Eating of their own feces, coprophagy, is not infrequent, and is especially notable in one of the highest types — the Chim- panzee. Perhaps occasionally coprophagy may be due to some defect in diet. There is no instinctive disgust at excrement in the lower animals any more than there is in the uneducated child. Nevertheless, eating feces cannot be healthful, and probably does not occur in nature ; and occurs only in the human with mental disease. Some of the insane acts of animals if prevalent in the wild would probably cause the extinction of the race. Such are killing of the 3'oung by the father and by the mother ; killing of the female by the male, usually during rutting time, in some instances reminding one of Sadism in man. This kind of sexual killing does not often occur in the wild. The female has a better chance to escape, and the male probably does not feel so inclined to damage her when he chooses her himself as when she is chosen for him by his gaoler. When the mother devours her young it is usually shortly after birth. I have, however, the record of a Jungle cat {Felis chaus) who ate two of her FOREWORD 7 kittens when they were seven weeks old. Some of the domestic animals devour their young ; the sow often does it, and occasionally the bitch. Sucking, gnawing and eating parts of itself or of a cage-mate is not uncommon in a variety of animals. Bears lick their paws until they are sore ; a monkey may gradu- ally gnaw away its tail from the tip to the body ; an ocelot {Felts chibigonason) bit open his scrotum and devoured his testicle; a Tasmanian devil (Sarcophilus ursinus) bit off one of his front feet at the wrist; a monkey may gradually gnaw away its fingers ; and numerous other self-inflicted mutilations occur. Often there is a local irritating cause, as skin disease, lice, or freezing. But in many cases no local cause can be found, as no local cause can be found for thumb-sucking or nail-biting in the human. The surgery done by monkeys on their frozen fingers and toes is interesting. After the flesh has sloughed the monkey bites off the protruding phalanges, apparently without pain, so that satisfactory well-covered stumps are made. Animals often mutilate their cage-mates in an amicable way as distinguished from fighting. A bear may lick its mate's ears until the hair and skin are gone. A monkey may eat its mate's tail or patches of its skin, the victim lying placidly while the process goes on. Many animals are addicted to perverted acts on their own or their mate's sexual organs. It is probable that the phenomena just mentioned are due to confinement, idleness and ennui, and that they do not often happen in nature where an animal is kept busy seeking his food, fighting and avoiding his enemies, attending to his mate or mates, and meeting the various vicissitudes of his environment. It should be remembered, however, that the members of a wild species vary in intelligence and temperament, as humans do. There are morons and perverts among 8 FOREWORD animals in the wild ; but not being coddled by the normal members of the species, they have a poorer chance than has the subnormal human of surviving and of transmit- ting their peculiarities. Fear, ennui, loneliness and nostalgia, by affecting the minds of captive animals, react on their physical condi- tion. Some animals have the fear of man bred in them. The young often show it from time of birth. This is especially common in animals that have survived for gen- erations in proximity to man. It is one reason for their survival. The mother and father may have become tame and gentle in capti\dty and yet the young one may be a wild thing from birth. Such fear is sometimes uncontrol- lable, an apparently slight cause making the animal dash itself against the fence of the enclosure. It is not mere speculation to discuss the physical effects of the emotions on the animal body. It has been shown that fear, anger, and grief bring about distinct measurable physical changes. Dr. Corson-AVhite has found that the red cor- puscles are increased by over two million per cubic centimetre in the blood of a cat frightened by a dog bark- ing at it. The amount of blood sugar is also increased. Such observations are suggestive in a consideration of the changes that may occur in a captive animal sub- jected to acute and chronic fear. The monotony of a captive animal 's life is broken only by feeding, the sight and sounds of others in the same building or nearby, and by visitors. Many animals show their appreciation and pleasure when visitors approach, and some of the more intelligent animals, bears and monkeys and some birds, *' show off " apparently to keep the visitors there. When there is nothing doing, some stand swaying their heads, like a weaving horse, or pacing the cage, inanely tagging at each turn the side of the cage with the head or other part of the body — often so persist- ently that a sore is produced. Nearly all animals are social and suffer from loneliness when kept by themselves. FOREWORD This is true even of the lowly forms. The keeper of the reptile house reported that a giant tortoise became despondent and refused to eat when his companion, a leopard tortoise, was taken from him, and that he braced up as soon as the leopard tortoise was returned. It is not necessary that the companion be of the same species, or even of the same family. A lion or a tiger may be satis- fied with a little dog for a companion, and there was an African rhinoceros at the Philadelphia Garden that was very discontented and unliappy when alone and became perfectly satisfied when she was given a domestic goat as a cage-mate; and the huge rhinoceros stood for a good deal of butting and bullying from the goat without retaliating. A sympathetic keeper may do much to relieve the loneliness of the animals in his care. Nostalgia, or homesickness, has been felt by all men. Some have died of it. The tradition among writers is that it affects young people and those who have been living nearest to a state of nature. In this country the American Indian and the negro are affected more than the whites. Much was written of it after the Franco- Prussian War and the American Civil War. It is a real condition, capable in extreme cases of causing death and of so weakening the sufferer as to make him more suscep- tible to the invasion of other diseases. At the present day we hear less of it among civilized people than formerly, perhaps because the conception of home has been broad- ened by modem methods of intercommunication. The wild animal's conception of home is narrow; he comes directly from it into an environment where he may see many other animals, but not one of his own kind. Pre- disposing causes of nostalgia are stronger with him than with the human. That home means a great deal to animals is shown by the migration of birds — the return of the carrier pigeon, and of the lost dog, and of the swallow, which returns every year to the same nesting place. 10 FOREWORD All animals long for the things of nature — open air, earth, grass and water. They are thrilled when their feet touch the sod. Even the hippopotamus gambols when he leaves his concrete house and his feet touch earth and grass. The face and carriage of many animals cannot express feelings as in the human, though it is not unreasonable to assume that animals may indicate feelings by expression understood by their mates, though not understood or even noticed by man. When they can express it in a human way their feelings may be read. The dejection of nos- talgia is especially sho\\ai by anthropoid apes. Gorillas have been noted for it from the earliest writers. The orang is prone to it, shows it by his attitude and expres- sion, and sometimes dies of it. It is stated in A Handbook of the Management of Animals in Captivity in Lower Bengal, p. 130, that elephants have been observed to shed tears abundantly if forced to leave their old home and surroundings. How much other animals who cannot express homesickness may feel it, and how often it is a cause of unhappiness, depression and predisposition to disease, it is impossible to say. ]\Iost wild animals in captivity are sterile. The reason is not kno^\Ti. It shows the profound effect of captivity. It would be difficult to determine whether the sterility of a mating is the fault of the male or the female. There is no apparent rule for sterility. Some families are always sterile in captivity, others are fertile, even with very unfavorable surroundings. The deer, horses, hippopotamuses, pigs, goats, sheep and oxen, are good breeders; while antelopes, rhinoceroses, giraffes, ele- phants, are poor breeders. Some members of a family may be good, others poor. The lion and puma breed fairly well; the tiger, leopard and jaguar, very poorly. Bears breed well, but the mother usually destroys her young. FOREWORD 11 We cannot mate mid animals and birds simply by putting males and females together in the same cage. Domestic mammals and birds usually mate under such conditions, but mid ones often refuse. Many mammals and probably all birds that are not polyandrous or polygamous reserve the right to select their mates, and if the sexes are put together by man they may view each other with indifference or with animosity. There are many males and females of the same species of mammals at the Zoological Garden that will not consent to live together. A male monkey in a cage with several females will very often select one female for his mate and will have nothing to do with the others. Among monkeys fertility varies greatly. It is not practical to determine the ratio among the various kinds, as some kinds are much commoner in zoological collec- tions than others. I think that in general the Old World monkeys (Cercopithecidce) are better breeders in cap- tivity than those of the New World (Cehidce). The anthropoid apes are very poor breeders indeed; of the many gibbons, orangs, and chimpanzees, that for years have been captive in Europe and America, it is probable that only the chimpanzee has bred, and that very rarely. Refusal to mate, sterility, infanticide by father and mother, and sexual killing keep down reproduction in zoological gardens; and the number of young ones is a good indication of the character of a garden and of the provisions made for the happiness, comfort and health of the animals. With the birds in a zoological garden the conditions for nesting and laying are not good. Caged birds have no material for a nest, no privacy and rarely lay an egg. The outdoor water birds and the outdoor upland birds with natural surroundings, with secluded retreats, lay and hatch very well. Birds like mammals apparently are indifferent to publicity when copulating, but seek 12 FOREWORD seclusion for laying and nesting — from maternal fear for the safety of the young. The sexual instinct in indoor caged birds in a zoologi- cal garden is dormant. Very few copulate and very few lay eggs; pigeons and Mexican conures {Conurus holo- cMorus) are exceptions to this general rule. Probably because the sexual instinct is dormant the males never fight over the females among perching birds, and very rarely kill each other. In some species of finches, however, as the chestnut-eared {gn. Amadina), the females fight among themselves if there are not enough males. Ovoviviparous reptiles breed more often in captivity than one would expect ; and egg-laying snakes often lay eggs, which of course are only hatched artificially. Birds suffer less than mammals from the psychologi- cal effect of captivity. The mental development of a bird is much lower. With few exceptions, like the ruffed grouse, the bird accepts captivity easily and becomes tame, though he ^dll not stand being touched. He views his keeper and visitors with indifference or friendliness. If a bird house is bright, cheerful and sunny, all the inmates thrive and appear to be happy. These conditions undoubtedly affect the health of the bird, as is evidenced by their plumage; bright colors that are lost in a dark and gloomy house are retained and developed when the house is cheerful and sunny. There are some birds, how- ever, that never retain their colors in the captivity of a zoological garden. Among them are the scarlet ibis, the American flamingo, and the roseate spoonbill. It has been suggested that the loss of color is due to the lack of something in the diet, mineral or organic, that the bird gets in its natural habitat. Tame scarlet ibises living with the chickens about the dwellings of natives in Venezuela retain their brilliant color. The material of the beautiful red color on the under surface of the wings of the touracou contains copper, yet these FOREWORD 13 birds retain this color very well in captivity, even after several moultings. The source of the copper has long been uncertain. In nature the birds are fruit-eaters, and their diet in cap- tivity consists of bone meal, zweibach, corn meal, wliite potatoes, eggs and carrots — foods that are usually assumed to contain no copper ; and no copper utensils are used in the preparation of the food. Dr. John Marshall, however, writes me that all the common cereals contain minute quantities of copper; and Dr. Leon A. Ryan, University of Pennsylvania Medical Bulletin, June, 1907, states that copper may be found in animal tissues. Dr. E. P. Corson-White has found traces of copper in the bone meal used at the Philadelphia Zoological Garden. The copper in the red color of the touracou's wing therefore comes from the food. It is probable that a bright and cheerful bird house does not influence the color of birds by the direct action of light on the color as much as indirectly by improv- ing the health and spirits of the birds. Coloration in birds is a very complicated proposition. It depends upon age, sex, season, health, light, heat, moisture, mode of life, and food. No one bird house can combine all the conditions necessary for the retention of natural colors in every species. The desert species from a habitat of intense light and dryness require for their color a dif- ferent environment from the forest species, from a habitat of shade and moisture. The suppression of sexual feeling in captive birds may influence color. In nature the finest colors are attained by mating birds. It may be said that all animals — except those of noc- turnal habit — have a feeling of joy and well-being in fine weather and bright surroundings that reacts favorably on the general health. The variability of the breeding period induced by captivity in many animals may be mentioned with sterility. It was shown some years ago in the Philadel- 14 FOREWORD phia Garden by the European brown bear wliich in one year gave birth on January 16th, and in the following year on July 25th. It is another evidence of the profound effect of captivity on the captive animal. I know of no observations of the effect of captivity on the period of gestation. There is considerable mortality among captive animals from killing of cage-mates. I do not refer to sexual killing, already mentioned, or to fights over a female. Often males, with no females near, cannot be kept together ; probably sexual jealousy is at the bottom of it. Antelope and deer are especially inclined to scrap. Even a large enclosure \\dll not save the weaker male ; the stronger follows him with horrible persistency, some- times for days, around and around the enclosure, often at a walk, but always on the offensive, at least during the day ; until, careless from weariness, the weaker is caught unawares and finished by a horn-thrust in the side. Both birds and mammals often kill their mates when the mate is sick, or " down " from injury or disease. All animals hate sickness and death, and show their dislike by attacking or shunning it. Birds may get on happily together for months until one becomes sick, and as he crouches in a corner with ruffled feathers the others pick on him and finish him. The same is true of manmials, the sick one being horned or tramped to death by the mate with whom he had formerly been on most friendly terms. The keeper often reports an animal ''killed by its mate," whereas the mate has only given the coup de grace. This brutality is not universal. Rarely a parrakeet will stand guard over his sick and dying mate; and we have seen a ratel — of a ferocious family — stand guard over and resist the removal of his sick companion. The diagnosis of disease in wild animals is unsatis- factory ; usually impossible ; clinical study as we know it in the human is impossible. We know that the animal is sick, but not why. A certain group of symptoms accom- FOREWORD 15 panies all diseases — dull, rough coat or feathers, refusal to eat, weakness in the hind quarters, and finally getting down. They rarely show symptoms of pain — or at least we cannot read the sjonptoms. The pain of acute pan- creatitis in man is violent, yet many animals die with it and we cannot tell that they suffer. Animals do not suffer as much as the human, and they stand the ravages of disease better than the human. At autopsy we often wonder how the animal could have lived with the condi- tions that are found. A monkey may be apparently well until a few days before his death, though his lungs and abdominal organs may be a mass of tubercle. A small red howler monkey (Alonata seniculus) was in apparent good health, playful and lively until twenty-four hours before his death from acute pancreatitis, though his stomach and intestines contained fifty-one nematode worms, some of which were eight inches in length. As diagnosis is unsatisfactory, so is treatment. Usually all we can do is to treat symptoms ; and by the time disease has advanced to the point of becoming exter- nally noticeable, it has usually gone beyond the reach of medical treatment. It must also be remembered that drugs vary very much in their action in different families of animals. Nux vomica will not kill the gallinaceous birds of North America, and Tenant says that in Ceylon the hornbill feeds on the fruit of strychnos nux vomica. The pigeon is immune to opium. The FelidcB are said to be unusually susceptible to carbolic acid ; veratrum viride is harmless to sheep and elk, but poisonous to the horse ; dogs can take with impunity large quantities of cyanide of potassium. These statements are true when the drugs are administered by mouth — the usual way of giving them to wild animals. The action may be different if the drugs are administered intravenously or subcutaneously. Variations in effect when they are administered by mouth are often due to chemical variations in the digestive secre- tions. It is probable that the action of cyanide of potash 16 FOREWORD on dogs depends on the amount of hydrochloric acid in the digestive tract. "When worms or their eggs are found in the stools vermifuges are used, and with some animals especially liable to infestation by intestinal worms, periodic doses of vermifuges are given as a prophylactic. Turpentine is given to the zebra at fixed intervals for the round worm ; santonin, male fern and areca nut to the carnivora for the various worms that are so common in the intestinal tracts of these animals. The work of the Laboratory of Pathology is throwing light on the subject of diagnosis, and though from the character of the clinical material diagnosis can never be as satisfactory as in the human, yet we may fairly hope for improvement. Prophylaxis is our chief reliance, and always will be. DISEASE IN CAPTIVE WILD MAMMALS AND BIRDS SECTION I INTRODUCTION " We have also parks and enclosures of all sorts, of beasts and birds; which we use not only for view and rareness, but likewise for dissections and trials, that thereby we may take light what may be wrought upon the body of man." The purpose of a menagerie under the auspices of a zoological society can scarcely be put into better words than those found in this quotation from Sir Francis Bacon's New Atlantis. Apt as this description of the mythical island's collection may be, it is but a reflection of the teachings of Plato 's original legend of a perfected community, and the practical applications of these teach- ings by Aristotle in his Anatomy and Physiology of Animals. The history of human study shows a constant investigation of lower forms of life, ever broadening in its scope, ever more satisfying in its explanation of biologic problems and ever increasing in value from an economic standpoint. If, however, all animals are to be subjected to ''dis- sections and trials" there inevitably will come under observation many specimens presenting variations from the accepted mean or standard or even from an average for their kind and therefore approacliing what may be called pathological. The desire to explain the abnormal has had the effect, during the half century since Virchow defined cellular pathology and Darwin systematized the world's knowl- edge of comparative biology, of directing attention to comparative pathology and of stimulating the study of 17 18 DISEASE IN WILD MAMMALS AND BIRDS veterinary medicine. Moreover in the past twenty-five years much work has been done and many isolated pub- lications have appeared upon the diseases of wild animals, notably Bland-Sutton's work, Evolution and Disease (1895), a thoroughly scientific and most charmingly writ- ten book, but rather elementary in its approach of the subject of pathology, and Wood Hutcliinson's Diseases of Animals, a more or less popularly presented treatise. I am unaware, however, of any systematic monograph upon the subject wherein we may find data showing the char- acter of pathology in the various animal groups or the incidence of the various lesions. The reports of some zoological gardens contain the result of medical and pathological data collected for the report period. The publication of greatest merit and value is that from the Zoological Society of London, whose huge collection studied by a large official personnel makes it possible to present valuable data. The New York Zoological Park uses its material in a similar manner and has been able to explain some of the knotty problems so frequently met in wdld animal collections. Here at Philadelphia it has been our practice now for twenty years to perform an autopsy upon every mammal and bird that dies, and upon all of the large or important reptiles. There is no aquarium connected with the Garden. The office of the society keeps a record of the arrival and a general description of every animal so that a brief history of the specimen is usually available. The keepers are required to observe their charges regularly and closely and to report any abnormalities to the officials of the Garden. Somewhat detailed discussions upon signs of sickness will be given at appropriate places, where also a few remarks upon treatment wiU be included, but as this work is not intended to be a treatise on therapy and since this subject does not differ from that referable to domes- ticated animals, little space will be devoted thereto. Upon death a complete autopsy is performed and the INTRODUCTION 19 findings are recorded upon a printed form from which, when the histological, bacteriological and parasitological studies have been completed, a set of cross index catalogue cards are typed; these are divided into the principal diagnoses and determinations. The report of the Zoo- logical Society, appearing at the end of their fiscal year, February 28th, contains a resume of the observations for the year, together with notes of interesting cases and experimental work. There have accumulated the records of nearly six thousand autopsies and upon them as a basis has been founded the following report of the incidence and nature of pathological manifestations in the various animal groups, using also as additional data, published reports from other gardens. The book might be described as a collection of our studies, parts of which have appeared as separate articles, but most of which are entirely new, put together with as much connection as the subject matter will permit. The zoological and pathological literature has been consulted very extensively, but except for the reports of zoological societies and the publications of special students, it usually rep- resents isolated notes by travellers and veterinarians so that many articles may have been overlooked. Therefore no claim of perfect completeness of reference is made, the statements resting chiefly upon our own records. The subject will be approached from the stand- point of description and incidence, but it is inevitable that comparisons and contrasts must be noted. Into the realm of evolution (1) I shall not venture because I appreciate a lack of adequate preparation for such an attempt, and because, even if such were not the case, the material at hand is lacking in data upon fishes, many kinds of reptiles and invertebrates. ( 1 ) Those who are interested in the subject of disease in its effect on evolution are referred to Morley Roberts, Proceedings, Zoological Society, London, 1918, p. 247. 20 DISEASE IN WILD MAMMALS AND BIRDS A direct and practicable application of these data will be in the direction of explaining some of the pathological states in domestic animals and man. There are indeed many disease entities or syndromes in these groups for which no useful hypothesis has been advanced, while for others a partial explanation has been offered, usually, however, inadequate wherewith to form the basis of rational prevention or therapy. Thus, for example, essential emphysema seems to be limited to the animals of civilization ; on the other hand, the anatomical basis of exophthalmic goitre may be seen throughout nearly the whole animal kingdom yet the clinical phenomena belong characteristically to man, and are occasionally seen atypically in the dog. While it may be impossible to give a complete comparative anatomy and physiology for each of the pathological states, the attempt will be made to treat all subjects analogically through the zoo- logical orders. The experimental pathologist may find the records of the Garden useful in his work. For example, he can know that rodents are not prominent among the orders shomng spontaneous arteriosclerosis, but that nephritis occurs among them in about a quarter of natural deaths ; or he may learn that the Primates have a good cardiac reserve while the Marsupialia have not. Too often experimental work is not based upon facts including natural probabilities. A collection of pathological data such as is presented in the following pages may be of assistance to vet- erinarians and managers of zoological gardens in the diagnosis of sickness in animals, both wild and domesti- cated. We do not presume to offer a system of veterinary medicine, but it is possible to introduce certain objective findings of practical hygienic and therapeutic value. Such observations are, however, limited and in our experience at the Philadelphia Garden the diagnosis of disease in a wild animal, excepting of course those which are per- INTRODUCTION 21 fectly self-evident, is more often speculation and conjecture than at all well grounded. It is not uncommon for animals to come to autopsy presenting a perfect galaxy of abnormalities, yet the closest antemortem observation failed to reveal unusual conduct or appear- ance. On the other hand specimens are frequently opened whose organs fail to contain any lesions discoverable even by careful study. Dr. Henry Chapman, sometime prosector to the Society, once made a remark in this con- nection— "Why do they die or how can they live so long." Space is given to this phase of the observation of wild animals in order to emphasize the difficulties of interpret- ing their conditions, but of course it should be understood that certain data of value may be gained by close atten- tion to the details of their normal behavior and to changes which occur indicating that something is wrong. The naturalist and the trained animal keeper are, in our opinion, better judges of a wild animal's condition than is the veterinarian, unless he be at the same time a zoologist and have long experience with a menagerie. My own observation of dogs and horses leads me to think that more acumen is needed to interpret the actions of wild animals since they seem to have greater natural reserve, and of course in regard to them there are many more variables since we see fewer specimens of each species than we know familiarly among domestic varie- ties. The principal objects for observation are, as in veterinary medicine, the eyes, the hair and skin, the mucous surfaces, the droppings, the condition of the abdomen, the appetite and the desire for water. Physical examination is limited to tractable beasts and those which can be caught and handled without danger to the per- sonnel or unusual fright and damage to themselves. In the interpretations of physical signs in tractable animals, such as many ungulates and some monkeys, the experi- ence of the trained veterinarian is of the greatest value, but this fails amongst carnivores and birds. It might be 22 DISEASE IN WILD MAMMALS AND BIRDS said that anesthetics could be used for a thorough exam- ination, but this would be undesirable for a seriously sick animal and it is, in our experience, none too safe a pro- cedure although often perfectly practicable. Animals do not like to be molested much as they may seem to enjoy attention, and when it is possible it is our practice to avoid handling them. It might be contended that observations upon diseased states in captive animals would not represent natural developments, in other words, not that which occurs in the wild. Such indeed may be true in regard to the infec- tious diseases, but since we are imperfectly informed as to the pathology of the wild state, we are obliged to accept and use the best substitute at hand. Moreover it seems perfectly fair to consider as characteristic for an animal or group, the physical and even physiological expressions of morbid agencies as we know them, even though the animals be at the time under conditions not natural to them. It would be perhaps incorrect to say that cirrhosis of the liver occurs in .6 per cent, of animals in the mid as is the case for our autopsies, since incorrect food and infections are potent in its causation ; on the other hand, our experience and some few data from naturalists and pathologists make it conceivable that tumors occur to this number in native states. The incidence of tumors in wild rodents is quite 'well know^n. Degenerations and fibroses, the result of parasitism, are knowm to exist throughout the entire animal kingdom. Further to illustrate how pathology is distributed in wild life, Plimmer's experience (2) with 500 rats {M. decumanus) might be cited. He found the following: Tubercle 3 times, tape worm cysts 10, Tryp. lewisi 49, empyema 2, tumor of jaw from old injury 1, pleuritis and hydrothorax 1. Bacteria w^ere found in 71 rats, 40 times in the lungs, 31 times in the spleen ; saccharomyces w^ere found 16 times in the lungs. Dr. W. L. Abbott reports to us personally that he (2) Proceedings, Zoological Society, London, 1911. INTRODUCTION 23 has repeatedly found coiled exproventricular worms in the wild specimens he has collected. Not only are we informed of some isolated and individual pathological states but the existence of epizootics of communicable disease among wild life is well authenticated. The simple citation of the extermination of deer in one section of Colorado by pleuropneumonia will suffice to illustrate this point. Other examples are, however, interesting. The occurrence of changes in the jaw bone almost certainly those of actinomycosis is reported by Blair, the specimens being shot in the ^\'ild and believed never to have been near civiUzation. The white-tailed deer of the Swan River Valley in Montana, are know^i to be constant carriers of liver-flukes. It would seem therefore that it is not unfair to use material gathered from animals under somewhat unnatural conditions as representing the reaction of the zoological orders to pathogenic agencies. Such conclu- sions must however be made very guardedly, for it is probable that not over ten per cent, of the total number of mammalian and avian species are to be observed in captivity. Because of the number of orders and the great variety of genera included in the present study it is probable nevertheless that the lesions are fairly representative of the whole animal kingdom. However, the nimibers and percentages given should be read to indicate the probabilities and should not be interpreted as implying the mortality relationships since different varieties have differing powers of resistance to the same pathological state. The margin of safety in any given group for one or several dif- ferent disease entities cannot at present be stated with any degree of precision but this factor is doubtless very great. The work of physiologists suggests that there is a reserve power in the human lung sufficient to sustain life until five-sixths of the functionating organ is useless, and 24 DISEASE IN WILD MAMMALS AND BIRDS I shall quote a case of an opossum wherein only one-tenth of the respirable surface seemed to have remained; we have repeatedly seen both lungs of a monkey apparently entirely solid. Such physical vital incompatibilities might be exemplified by many other cases, but when one reviews the physiological margin of safety, inexplicable and contradictory instances are equally numerous. 1 have seen a male deer run a doe against the fence and butt her, without result, whereas in an apparently similar occurrence the animal would be dead in a short time. Numerous instances of slight enteritis of a short stretch of duodenum or ileum have killed, with almost nothing to be found microscopically, and on many occasions we have been chagrined in being unable to discover the cause of death. The capacity of self-healing is a variable one, but seems in direct proportion to the quietness and seclusion possible for the animal and inversely to the chance of bacterial infection. The effect of captivity has been the subject of much speculation. For the preservation of health it would seem that animals require periods of rest and activity, thor- ough elimination, possibly a moderate exercise of their procreative functions, but most of all, appropriate food obtained by the physical effort we term chase. All but the very last condition is supplied in a measure in well managed collections. The degenerating effect of the absence of chase must be admitted. An interesting and suggestive example of this was noted by Mr. Jones at the London Zoological Gardens. He observed the skull of a lion that had been in captivity thirteen years, in which the canine area of the face and the part of the skull acting as the insertion for the seizing and holding muscles had undergone atrophy while the chewing muscles with their bony bases had remained normal. Numerous examples of disease atrophy are on record and those of a physical nature must have counterparts in the realm of physiology. The size to which an animal will attain INTRODUCTION 25 cannot be estimated by the examples seen in menageries. Judging by the accounts of collectors and hunters and upon the more reliable of the moving picture displays of wild animals in their native haunts, it would seem prob- able that under normal conditions of habitat the average size of wild beasts is considerably in excess of that in park specimens. The effect of captivity may also be felt in the direction of reduced resistance to infectious diseases. Brooks, of the New York Park, expresses the view that captivity increases susceptibility to bacteria and causes paren- chymatous degenerations. In the latter direction it is interesting to learn that Seligman of London claims to have seen sudden deaths in wading and struthious birds from myocardial disease, without valvular or other lesions, for which he holds the enervating effects of cap- tivity responsible. It is well recognized that a species may be unusually susceptible to a disease that it has not encountered in its phylogenic development. Man illus- trates this peculiarity very clearly. Europeans were found exceedingly susceptible to sleeping sickness when they went first to the part of Africa inhabited by the tsetse fly, and the American Indians died in hordes when they met the tubercle bacillus for the first time. Judging by the ravages of tuberculosis in captive monkeys a similar susceptibility probably explains the matter for there are no entirely satisfactory records of this disease among them in the wild state. In so far as general susceptibility to infection is con- cerned, it may be in part due to one of the artificial conditions of captivity, that of inbreeding. This influence is undoubtedly very great, both by chance in families, and by intention on the part of dealers as well as the mating which occurs in menageries. However, it is not known how far inbreeding may go in the wild state so that one must be very careful about drawing conclusions in this particular. Several years ago, at the time we reported 3 26 DISEASE IN WILD MAMMALS AND BIRDS the neoplasms found at the Garden, discussion arose as to the effect of inbreeding, and thereafter some observa- tions were made in this direction. With the exception of the hyperplasias of the thyroid, not certainly of neo- plastic nature, in a much mixed-up family of wolves, we could find no evidence that inbreeding was responsible for tumors. Plimmer and Murray of London, seem to imply that some of their inbred animals are likely to have tumors ; reference to this matter will be made later in this book. In so far as diseases of the organic systems are concerning those of the bones seem to be the only ones in which inbreeding is significant. The individual resistance will be reduced of course by the unsanitary surroundings incident to trapping, ship- ping and storage, but this need not affect the figures or pathological tendencies of classes or orders. The effect of captivity is felt in another way. A very large percentage of wild life perishes during the first weeks or months after its capture, and in gardens the heaviest mortality occurs among the recent arrivals. The London Garden figures that from thirty-three per cent, to fifty per cent, of their total mortality is in animals that have not been in the garden six months and that die because they are not yet accustomed to their new sur- roundings. It seems to us, both from an academic and a practical standpoint, that this is a long time and should afford ample opportunity for the garden to study the specimen and for the specimen to become acclimated. These early deaths are perhaps to be ascribed in large part to failure of acclimatiza- tion but many are doubtless the result of infection acquired in the mid, in transit while in the hold of ves- sels, at quarantine, or in trains, or at the establishments of dealers. We have seen a few deaths which have fol- lowed behavior that might be hkened to homesickness. Perhaps the age at arrival has an influence upon the morbidity and mortality of wild animals, for it is easily INTRODUCTION 27 conceivable that the young and the very old might adapt themselves to new surromidings with much less readiness than the sturdy middle-aged adult. The age of animals upon arrival is very rarely known, and can only be recorded as "young," ''fully developed," and "old." This will have an effect upon statistics and when possible is noted in the text, but this is not practicable to the extent we desire. The meaning of "young," "adult," and "old" is not the same throughout the animal orders nor even within orders. Mitchell (3) has attempted to gain concrete ideas of the expectancy of life among animals by analyz- ing the records of the London Gardens. This gentleman bases his figures upon known ages and the length of time in captivity, from a combination of which data the specific viability and the potential longevity may be estimated. Such results, he admits, can only be approximate and they show Avithin classes and orders, a decided lack of uniformity. The terms "spe- cific" and "potential" longevity, coined by Sir Ray Lankester, apply, for the first, to the average length of life as it is affected by external conditions and those incident to procreation, while, if an animal be under ideal conditions it will attain the potential longevity which is longer than the former. These considerations have a biological and economic importance, while a knowledge of the pathology shown by the various groups may help to explain these durations of life. Contrariwise figures of the expected longevity may assist us in evaluating youth and senility in the causes of death but can hardly affect the comparative nature of the lesion. A resume of Mitchell's studies indicates that the higher apes have a potential longevity and a hardihood much less than man but still upwards of thirty years. As one investigates lower in monkeys, life periods become shorter, while in the next order, Lemures, the length of (3) Proceedings, Zoological Society, London, 1911, p. 425. 28 DISEASE IN WILD MAMMALS AND BIRDS life rises. Carnivora have a reasonably good vitality, their potential periods varying from ten years in the foxes to thirty-three years in bears. Insect eating animals are short lived, three years being a maximum. The Bat family shows great variations, the greatest Ufe being not over seventeen years. The Rodentia have long lives compared to their sizes — twenty years in porcupines, fifteen years in squirrels, thirteen in marmots, nine in agoutis and capybaras, and three in dormice (which is also about the maximum for the rat). Hyraces live four years on the average. Proboscidea, although reputed to live to great age, probably rarely live a half century and may be said to have an expectancy of twenty to thirty years. Perissodactyla (horses, tapirs and rhinoceroses) while they may live half a century, have an average life of between fifteen and thirty years. The closely related Artiodactyla fall into two groups, a first comprising antelopes, sheep, goats and deer which rarely exceed seventeen years, and a second consisting of cattle, camels and giraffes, which vary in expectancy from eighteen to thirty years. The smaller members of the Ungulata have in relation to size a relatively greater viability, the ruminants, however, having on the whole a low viability. Marsupials vary from a maximum of seven years in the opossum to eighteen in the wombats, but none of this group has a good viability. The Aves as a class or if compared according to dietary requirements, have longer potential ages and better viability than mammals. Pas- serine birds average twenty years and many live to sixty, while the Picariae approach the former figure but do not have such good ^dability. Psittaci and Striges may live a half century but the resistance of the latter is much reduced by any unfavorable surroundings. The rapta- tory birds live fifty years, but their viability is variable. Herodiones have a maximum expectancy of thirty years and good resistance, while their relatives, Steganopodes, may live fifty years, and Odontoglossae have a good INTRODUCTION 29 viability, up to twenty years. Anserine birds may live to be fifty, and, unless conditions are quite unfavorable, have a good resistance. Columbae may under good con- ditions live to be fifty. Gallinaceous birds may only be expected to survive twenty years, a figure also given for Fulicariae. Alectorides may live up to fifty years. Limicolag, though they do not thrive in captivity, may live thirty years. Impennes live poorly under artificial con- ditions, the greatest record being twelve years, a figure also holding for Crypturi. Struthiones, if the conditions be right, may live fifty years. Because of the variable specific longevities, it is fre- quently difficult to decide when an animal is senile. Man is said to be as old as his arteries, and his span of life nowadays is in the neighborhood of half a century. Par- rots exhibit lesions of the vascular system comparable to the arteriocapillary fibrosis of human beings, and their expected longevity is about the same or a little greater. From a study of our cases of this lesion in parrots it can be said to appear quite early in life and not to lead to organic disease as it is alleged to do in man. It is, how- ever, interesting to note that in those animals which are supposed to have the longest specific lives — elephants, snakes, anserine and raptatory birds, parrots — there is relatively low mortality and fewer infectious diseases are encountered. The last part of this statement should be qualified by stating that anserine birds and parrots are quite susceptible to mycoses, in all probability from musty food, which raises their death rate, but as this is accidental and artificial, it can be excluded from consideration. In a rough way there is a direct relationship between the size of an animal and its longevity, but this is not close enough to be a reliable guide ; whales and elephants live a long time, but so do snakes and parrots. Within orders this relation of size and expected longevity is more easily seen but is not absolute. I cannot state, according to my 30 DISEASE IN WILD MAMMALS AND BIRDS present studies, that there is an unqualified relationship between the size and expected longevity of an animal and its pathological lesions. The immediate surroundings and the management of captive animals have a very direct and important bearing upon the mortality and perhaps upon the incidence of morbid processes but probably not upon the character of the latter. A full knowledge on the part of the personnel of a zoological society concerning the habits and habitat of every animal in their keeping is essential, to which must be added a group of interested keepers. In engaging the last, it should not be forgotten that certain men have ''a way" with animals and that others cannot manage themselves. The enormous literature at the disposal of the naturalists permits executive officers to formulate a plan of housing and feeding with fair accuracy for each kind of animal, but of course it is rarely possible to obtain in sufficient quantity the natural food {e.g., ants for ant- eaters). In so far as food is concerned it seems that with a few exceptions like the one just mentioned, the substitu- tions made at the zoological gardens are nearly satisfactory. The elements in which the captive diet is poor are the inorganic salts and vitamins since Dr. Corson- White, some of whose work is included in a later chapter, has shown that for those animals which our statistics indicate as most prone to have rickets and osteo- malacia, the available phosphorus and calcium are low, and one vitamin was also below the desired quantity. In this regard, however, I am not at all convinced that diet alone will suffice to explain these degenerative osseous diseases ; I shall take this up more fully later. Careful inspection of all food should be made and cleanliness (sifting of cereals, protection of meat from flies, etc.), is indispensable. The mortality among our camivora has materially decreased since the horse meat after butcher- ing was placed in covered galvanized iron pans. There INTRODUCTION 31 are many problems of feeding, too numerous to be cov- ered in a survey of this sort, which must be solved, and it is a credit to superintendents that this they have studied carefully. There are two problems in the management of animals upon which much difference of opinion exists, namely the heating of houses and the material of which cages are made. It seems to be the practice in many gardens to keep animals very warm. Dr. Chalmers Mitchell states unqualifiedly that adult animals do not have to be kept warm, and that even an equable temperature is not demanded, variations in temperature having a distinctly stimulating eif ect. However he main- tains that they should be kept dry and must be supplied with a shelter. This is in accord with the experience at the Philadelphia Garden, since for many years we have allowed access to the open air all winter to every animal that could stand it. A large group of macaques has now lived entirely in an open "band stand" cage for nine years with a lower mortality than in the rest of the monkey collection, which is permitted to go indoors some of the time. Occasionally one in poor health is frozen to death, and healthy ones may lose fingers, toes, or a part of the tail, but the general condition is so much improved that they present an attractive exhibit to visitors. Unless a storm be of great severity, wild animals are usually indifferent to it although they may seek their shelter. Snow apparently is no source of fear to them, and many enjoy playing in it. The general principles of the enclosure should be proper lighting, free access of air, dryness and shelter in time of storm, the last so arranged that the sleeping place is well protected. Appropriate arrange- ments should be made for nocturnal animals, regardless of their visibility to visitors, if their preservation is of importance. The hygiene of communicable disease has influenced everyone to use concrete and metal for cages. These sub- 32 DISEASE IN WILD MAMMALS AND BIRDS stances are without doubt most simply kept clean, but they are heat-conducting and remain cold or damp longer than wood or the ground. It may be claimed that the latter two cannot be disinfected so well, but this need not militate against their use. Wood can be disinfected by sunlight or by mechanical cleaning plus disinfectants, by a blast lamp and by paint. The ground will disinfect itself if allowed to lie fallow for a time, or it may be turned over after sprinkling with lime. It is fair to note that the New York Zoological Garden reduced their mor- tality, especially from verminous pneumonia, by changing some deer herds to concrete paved enclosures; if that were the only change made the result would be very significant, but it should not be forgotten that another clean ground range might have served as well to a herd from which the infected ones had died. My own observa- tions with guinea-pigs, rabbits, mice and dogs lead me to believe that they thrive and breed better on wooden floors than on metal or stone. I have tried to work out figures to show that more animals die when housed in enclosures of stone and metal than when upon the earth or on wood, but the attempt has been unsuccessful chiefly because of the presence of epi- demics and parasites, principally among the birds. The attempt was further embarrassed because some members of an order are housed on both floorings. However, there was no great advantage for the metal and concrete floors even after the epidemic had been discounted. This Gar- den does not have a great number of pneumonias, a disease said to be favored by dampness and cold, but those that occur are chiefly among the small mammals, on wooden floors and in the large bird house in cages of con- crete and metal. However, the construction of both these houses permits the visitors to approach very close to the cage, a factor that doubtless explains the dispropor- tionate incidence of inflammation of the lungs. In so far as outdoor fowl and ungulate ranges are concerned, they INTRODUCTION 33 should be changed frequently under the best conditions since occasionally one will find groups doing badly until moved. Moreover the ground becomes contaminated mth parasites such as esophagostomum and heterakis, infestation with which while not very serious in itself, may lead to fatal infection with bacteria. The effect of animal parasites upon the morbidity and mortality of wild beasts and birds in captivity is by no means clear, and Doctor Weidman and I are inclined to be sceptical, with certain reservations of course, of their great importance in the death rate. Doctor Weidman has kindly agreed to contribute a chapter upon the general distribution of protozoal and metazoal parasites with a summary of their probable pathogenic importance. The groups known to have a decided pathological power might be divided into the toxic, the tumor formers and the mechanically obstructive ; certain parasites have properties placing them in two of these classes. The first group comprises the hemosporidia and hemogregarines, the uncinaria and some of the cestodes, forms which pro- duce hemolysis and hemorrhages with varying grades of anemia. The importance of this group is shown chiefly among the Aves, in which high grades of anemia are occasionally met from malarial infections, but cats and dogs or even herbivores also frequently suffer from hookworm. The tumor-producers are chiefly echinococ- cus worms, the cysts of which may grow large enough to occupy nearly the entire abdomen. A certain grade of anemia and general ill health accompany this hydatid disease, partly the result of a toxin and partly by damage to important viscera. Those parasites which obstruct mechanically do so by their own bulk or by an accom- panying inflammation, incited by them as foreign bodies or by bacteria which have gained entrance at the irritated point. This is exempUfied by the enormous collection of nematodes sometimes found in reptiles (a pailful was removed from a python) and by the tightly coiled or 34 DISEASE IN WILD MAMMALS AND BIRDS tangled thread and tape worms frequently found in birds. The effect of swelling by the mucous membrane under the influence of worms is illustrated by the infestation of the proventricle in parrots. Here spiroptera penetrate into and under the glandular layer which swells and pours out mucus, the total mass of nematodes, mucus and tissue obstructing the passage. Very many animals show parasitic infestation at post- mortem, but the percentage in which they can be said to be principal causes of death is quite small, while that in which they play a role as activa,tor of the terminal condi- tion is also small but indeterminate. The latter group comprise, together with the anemias mentioned above, certain forms of pneumonia, of hepatic and vascular lesions. Inflammations of the lungs from ascaris and paragonimus are fairly well known ; fortunately we have been troubled less with this than have most gardens, pos- sibly because we do not have such large herds of herbivora susceptible to it. Hepatic diseases from flukes, from coc- cidia and from amoebae we have always with us in small numbers, but they are unimportant excepting enterohep- atitis, a condition which appears in nearly all orders. This last disease, be it purely amoebic as in dysentery of man and monkeys, or like blackhead of turkeys and chick- ens or in the forms of quail disease, arrests the attention at once and evokes a desire to explain the association of large intestines and liver. Parasitic vascular lesions are relatively unimportant. Taking parasitic infestations by and large, there are close similarities throughout the entire animal kingdom, and the effects produced by a given genus will be repeated almost exactly in several others. The pathological pic- tures of anemia, of hepatic degeneration, of cystic degeneration, of colonic ulceration or of fibroses are simi- lar in different hosts, only slight variations in the type of inflaromation being noted, for instance in reptiles and birds as against the mammals. We have made rather close INTRODUCTION 35 observations upon the effect of parasites iii the produc- tion of neoplasms, incited by Fibiger's discovery of nematodes in the rat's stomach cancer, but, with the pos- sible exception of a papillomatous growth in the stomach of opossums from the action (?) of physaloptera, we have been unable to establish such an etiological relationship. A decision of the importance of parasites in any given case is not without its difficulty, and we are inclined to reserve judgment pending further analysis unless the effect of the invaders is unequivocal. Leiper (4) does not seem to credit animal parasites with a great effect on the mortality after a specimen has been in the collection six months since all the intestinal varieties he studied came from animals dying in that period. On the other hand the forms which invaded the internal organs and tissues were, in his series, from specimens resident several years in the garden. He seems to think the conditions of life at the garden favor the expulsion of intestinal worms. To what extent some intestinal worms may be commensal remains as uncertain as the value of certain bacteria in the gut tract. In man considerable importance has been ascribed to certain fermentative and putrefactive germs in the maintenance of a reaction unfavorable to strict pathogens and some observers have looked at them as possessing a digestive power. In the digestive tract of the animals eating large quantities of carbohydrate as cellulose, nature provides for its use by rumination and by supplying a large hind gut, by which means secondary mastication and bacterial decomposition of the cellulose capsule insures its full use. Possibly a similar usefulness may be finally ascribed to some animal microbes or even larger metozoa. The role of vegetable parasites in the causation of dis- ease among wild animals seems as undoubted as it is in the human being and the pathologic results are usually as (4) Proceedings, Zoological Society, London. 1911, p. 620. 36 DISEASE IN WILD MAMMALS AND BIRDS clear, at least for the entities of which we have exact data, based upon comparisons with man and domestic animals. There seems to be no essential difference among mammals between the pathological pictures of infectious septicemias, the mucous and serous membrane inflam- mations and tuberculosis for example. They are characterized by fibrinous, purulent or infiltrative inflammations which may go on to necrosis or repair, by fever, by leucocytosis and by evidences of resistance — all of these things occurring in a similar way throughout the class. Of course not all animals are receptive to all infections since specific racial and generic immunities exist, but the basic response in terms of pathology is similar. There are no normal means of judging the sus- ceptibility of wild animals on their native heath to the important pathogens of civilization, pneumococci, strep- tococci, staphylococci, cholera bacilli, the typhocolon group, the Friedlander group and others, but it is inter- esting to note that in captive conditions they evince some receptivity to these germs or their congeners. The pneu- mococcus takes a fairly heavy toll in zoological collections every year and the Friedlander bacillus, not a very com- mon cause of human pneumonitis, has been seen here and at London. Among the birds, however, quite distinct differences in some pathological processes occur, not only from the mammals but also within the class. As a whole birds do not produce pus as we know it in man, probably because of the absence from their leucocytes of a protein-splitting ferment; their leucocyte-producing organs do not seem to respond as readily to a virus, the place of purulent exudate being taken by a coagu- lum or necrosis. The former varies from a clear gelatin-like material seen upon serous surfaces to a thick mat or mass of coarse but short fibrinous strands. Necrosis may succeed upon the latter or occur so promptly as to appear like the original form of INTRODUCTION 37 degeneration. It is usually rapid, accompanied by a circumferential congestion but not associated with active phagocytosis. Giant ceU production is variable, but when developed the appearance is like that of large syncytia. Hemolysis is not marked in the simple infections but a hyperplasia of the mononuclear nodes of the liver is the rule. The function of this nodal increase is not quite clear. It has been always thought that the scanty bone marrow would supply the necessary erythrocytes, but we have seen these mononuclear areas fuU of pale red cells fitted with round nuclei and without pigment. The fibrin mentioned above does not have the delicate interweaving that we know in a fibrinous exudate in man. Tliis is inter- esting when we consider the composition of the blood and its coagulation in the Aves. The cell upon which human coagulation seems to depend, the platelet, is rep- resented in birds by the thrombocyte, which appears only up to about 50,000 per cubic millimetre. Coagulation time is relatively short and the resulting clot is firm and irregular. Perhaps this may have something to do with the nature of an inflammatory exudate. The response to infection on the part of birds may to some extent depend upon differences in anatomy, which are quite distinct, not only from the mammals within which class the anatomy is more uniform, but also from one avian order to another. These differences among the birds may be exemplified by the large foramina between lungs and air sacs in the water birds, a passage which permits infection, notably mycosis, to spread from the first to the second. Again the close apposition of the pancreas to the duodenum over a long stretch permits easy infection of the former from the latter. Still again the large renal-portal vein in the gallinaceous birds explains some of the infections of the liver sec- ondary to intestinal disease. The position of the lungs, deep in the thorax and fitted into recesses made by the sharp anterior border of the ribs and overlaid anteriorly 38 DISEASE IN WILD MAMMALS AND BIRDS by a rather firm air sac wall, makes it difficult for these organs to expand and therefore renders even a simple congestion a dangerous thing. The position of the ovary- subjects the shell-less egg to much danger from the intestinal area. These and many other peculiarities of anatomy affect the pathological picture in birds. To be sure there are also noteworthy differences among the Mam- malia, notably in the intestinal and genital tracts, but the pathologic response is not so varied as in the birds. "WTien due allowance is made for the kind of stomach and absorptive area, apparent differences can be reconciled. For example, there is little confusion experienced in comparing acute erosive gastritis or the follicular enteritis of an omnivorous intestinal tract (man or pig), of a sacculated stomach and absorptive tract (the marsupial), of a carnivorous gut (cat) or a herbivorous compound stomach vrith. its long digestive and water- absorbing surface (cow or camel) and an expansive muscular organ with a very extensive digestive area (seal). The type of lesion seems the same, in that inflam- mation, pus, necrosis, granulation tissue and cicatrices are comparable throughout the series. The size of the hind gut has been taken by Metchnikoff as an indicator of the possibility of intoxication by degradation products of digestion. He believes that the capacious colon of herbiv- ora and the short small one in carnivora explain the relatively greater life in the latter, because here less stagnation and absorption can take place. A reference to the expected lengths of life given before hardly substan- tiates this, and in our later chapters there will be found no strong indication that animals with large colons suffer with degenerative visceral changes more than those mth small ones ; nay even the reverse may be found true. In regard to epizootics the behavior of man and lower animals is similar except perhaps that during an outbreak a smaller percentage of the latter give evidence of indi- INTRODUCTION 39 vidual immunity and whole groups are apt to be carried off. Occasionally hygienic measures stay the ravages, at other times nothing seems to avail. Fortunately it is sometimes possible to sacrifice infective specimens and remove contagion. We have had few serious outbreaks, unless one might call our former heavy infection with tuberculosis in monkeys an epizootic. The principal ones were an unexplained water fowl disease which carried off one hundred and forty-six birds, an imported epi- zootic of quail disease which killed about the same number, a few cases of blackhead among wild turkeys, and a small group of cases of amcebic dysentery in monkeys and of thrush in passerine birds, and a small number of tuberculous pneumonias in snakes. Pathology may be difficult upon an anatomical basis, but when we engage to explain functional physiological defects we are surely embarked, with a poor compass and weak rudder, upon an uncharted sea. One knows, of course, that all animals require the same amount of food elements per kilo of body weight, that man eliminates his nitrogen as urea and uric acid, that monkeys do the same, that most other mammals destroy uric acid and excrete allantoin, that birds and reptiles form uric acid but chiefly urates, that there is an adaptation of alimentary tract and diet, that herbivores have a high threshold for carbohydrates, that there is a variable quantity of enzyme present in different organs and in different ani- mals, that vitamins, whatever they may be, are necessary for the growth of young animals, that hormones exist whereby correlations of parts are kept normal — but these things, rather than being learned thoroughly from ani- mals, have merely been substantiated by comparisons \\dth man. Constitutional diseases so-called, from which the necessity to investigate much of this physiology origi- nated, are little known in the wild animal. Many cases of so-called gout have been encountered and we have seen an instance of diabetes in a fox, but more extensive 40 DISEASE IN WILD MAMMALS AND BIRDS experience is needed for definite practical comparisons. This applies to thyroid and pituitary disorders and to the vague conditions we have at times been obliged to call marasmus or inanition. Some attention has been given to the study of diets for the wild specimens of our Garden, but no systematic observations have been made or records kept upon purely physiological subjects. Reference will be made at appro- priate places to accepted comparative physiological facts, but our statistics permit additions to such knowledge only in a limited manner and in isolated instances. Doctor Corson-White has very ably summarized the diet, ali- mentary tract and physiology of the zoological groups with the pathology as found in our records. A word might be added here as to the destruction of animals by injury from fighting and harassment by others in the cage. Fighting doubtless causes death, especially when males are together, but it is our experi- ence that in cases of traumatic death search should always be made to see if the resistance of the dead animal had not been reduced by some disease. This is well illus- trated in birds. Very frequently a specimen will come to autopsy with its head feathers plucked out, or with a bill- thrust in the wing or pelvic region. Such birds are not infrequently suffering from malaria, or heavy intestinal parasitism or from organic disease whereby the resist- ance and self-preservatory power has been decreased. The foregoing survey of the approach to our subject reveals the multiplicity of factors which affect the study of comparative pathology. No one of them can be entirely omitted, no one is without some effect upon the origin and expression of disease, and no one is fully understood. Yet it is to be hoped that a study of our material, accumu- lated under routine conditions and uninfluenced by any experimental procedures, will demonstrate the natural response of various zoological groups to morbific agencies. Perhaps reactively some of the modifying INTRODUCTION 41 conditions may thus be understood. It is also not unreasonable to expect that alterations observed as natural responses in a large number of specimens in nearly normal surroundings would serve as more reliable guides to investigative speculation than would changes in a few animals under artificial technical experimenta- tion. We hope that the few facts we have been able to record may afford someone a basis for further biological studies. It is also to be hoped that something has been learned which in the end will afford an explanation of the diseases of man. Too great optimism in this direction should be guarded against because the human being is indeed an animal sui generis and, from the standpoint of normal conditions of nature, a wild animal. The zoological classification found on pages 43-46 was compiled in 1903 by Dr. A. E. Brown on the basis of the British System. With a few exceptions the computa- tions in the text are made on the basis of zoological orders since the number of specimens in families is often too small and the complications of so many different figures would be confusing. The tables will be found to correspond to the sequence of the classification. Dr. Corson- White has, however, used for her analysis the dietary groupings. A carnivore in her chapter implies strictly a meat-eater, in the rest of the book one of the zoological group Carnivora. The Laboratory of Comparative Pathology at this Garden speaks for the earnest desire on the part of the Directors to use the material to its fullest extent, and I, acting for myself and my associates, wish to record our appreciation of the facilities offered to us for study, and for the broad-minded, scientific cooperation the Board has always displayed. The President, Charles B. Penrose, M.D., Ph.D., LL.D., was the active originator of the plan whereby this department was started, and he has given to it continuously the support of his rich experience. I wish to express for myself the deepest appreciation of his 4 42 DISEASE IN WILD MAMMALS AND BIRDS personal interest in my studies, and assistance which has been constructive and stimulating. Whether or not this present work prove useful to the extent that is hoped, the results from the Laboratory are such as to make the scientific world debtor to this gentleman. It is a duty, and a pleasant one, to record, though unfortunately in memoriam, my association with Arthur Erwin Brown, A.M., Sc.D., Ph.D., C.M.L.Z.S., for many years the Secretary of the Society and Executive Officer of the Garden. Doctor Brown as teacher was ever ready to help in the broad subject of biology, and I am proud to recall that he guided me also as a friend. The first director of the Laboratory was Courtland Y. "White, A.M., M.D., who served from 1901 to 1906, retiring then to accept a position in the City Laboratory. The foundation of the recording system is still in use essen- tially unchanged from his plan, and is a credit to his fore- sight. Our clerk and technician. Miss Harriet M. Phelps, has served the Garden faithfully and well since 1906. The condition of the museum is very much due to her interest and watchfulness. Thanks and appreciation for her work are felt by every one, the author most of all. Dr. F. D. Weidman has been our first assistant since 1911, and his work on parasitology has been of the greatest value, practically and scientifically. It is to be hoped that we shall be able to retain him indefinitely. Dr. E. P. Corson- White has in recent years taken an assistant position with us, armed for the work with a thorough knowledge of applied organic chemistry and immunology, and has already obtained useful results. ZOOLOGICAL CLASSIFICATION MAMMALIA PLACENTALIA Primates Simickdce Anthropoid apes. Cercopithecidce Old World monkeys (macaques, baboons) . Ceiidce .New World monkeys (capucins, howlers, spiders ) . Hapalidce New World monkeys (marmosets ) . Lemuees Lemuridce Lemurs, Loris, Galagos. Cabnivora Felidce Cats. Tiverridw Civets, Genets, Paradoxures, IchneumonB. HycenidcB Hyena. CanidcB Dogs, Wolves, Foxes, Jackalls, Etc. Mustelidce Marten, Skunk, Weasel, Otter, Badger, Etc. Procyonidce Raccoon, Bassaris, Coati, Kinkajou. Ursidw Bear. These are grouped sepa- rately as sub- -{ order. PINNI- PBDIA, illus- trating water carnivores. Otariidce Eared "Seal, Sea Lion. PhocidcB Common Seal, Walrus. Insectivora Tenrecidoe . .Tenrec. Solenodontidw Solenodon. Talpidw Moles, Shrews. Erinaceidce Hedgehog. Chiropteba PteropodidcB Fruit Bats, " flying foxes." VespertilionidcB Common Bats. EmbaUonuridte .... Snouty Bats, Free-tailed Bats. Rodentia SciuridcB Squirrels, Spermophiles, Marmots, CastoridcB Beaver. MuridcB Rats, Mice. GeomyidcB Pouched Rats, " Gophers." Dipodidce Jumping Mice, Jerboas. Heteromyidce Kangaroo Rats. OctodontidCB Capromys, Coypu. HystricidfB Porcupines. ChinchillidcB Viscacha, Chinchilla. Dasyproctidce Agouti, Spotted Cavy. Caviidw Guinea-pig, Capybara. Leporidce Rabbits, Hare. Proboscidea Elephant. Hyracoidea Cape Hyrax. 43 44 DISEASE IN WILD MAMMALS AND BIRDS Ungxtlata Perissodactyla (odd toed) Bhinocerotidce Rhinoceros. , TapiridcB Tapir. Equidce Horse, Ass. Artiodactyla (even toed) Bovidie Oxen, Antelopes, Sheep, Goats. Cervidce Deer, Moose, Elk. AntilocapridcB Prong-horned Antelope. GiraffidcB Giraffe. Tragiilidce Chevrotains, Muis Deer. Camelidce Camels, Llama. Hippopotamidce Hippopotamus. Suid(S Swine, Warthogs. Tayassuidre Peccaries. SiRENiA Sea-oow, Manatee, Durong. Cetaceia ^Vhales, Porpoises. Edentata Bradypodidce Sloths. DasypodidcB .Armadillo. M yrmecophagidce . . . .Ant-eaters. MARSUPIALIA Marsupialia Didflphyidiv Opossums. DasyuridcE Dasyures, Tasmanian " Devils." J'eramelidw Bandicoots. I'hascolomyidce Wombat. PhalangeridcB Phalangers. Macropodida: Kangaroo, Wallabies. ]\I0N0TREMATA monotkemata Echidnidce Echidna, Omithorhynchus. AVES Passeres Turdidce Thrushes, Robins, Etc. Sylviidce Warblers, Kinglets. ParidcB Titmouse. Troglodytidce Wrens, Mockingbirds, Catbird, Etc. Pycnonotidce Bulbul. Crateropodidcc Babblers, Jay -thrushes. OriolidcB Oriole. MotacilUdcB Wagtails. Dicruridce Drongos. Mniotiltidce Chats, Warblers, " Woodwarblers," Etc. Ccerebidce Sugarbirds. Tireonidce Vireos. Laniidw Shrikes. Ampelidce Waxwing. HirundinidcE Martins, Swallows. Meliphagidce Honeyeaters. Tanagridce Tanagers. PloceidcE Weavers, Whydah birds, Waxbills, Finches, Etc. INTRODUCTION 45 FringillidcB Finches, Sparrows, Buntings, Grosbeaks, Etc. Icteridce Hangnests, Troupials, Grackles, " Black- bird," Etc. Sturmdce Starlings, Mynahs. CorvidoB Crows, Jays, Magpies, Jackdaws. AlaudidcB Larks. TyrannidcB Tyrans. Cotingidce Bellbird, Cock-of-tlie-rock, Etc. PiCABLE TJpupce Hoopse. Trochilidce Hummingbirds. Cypselidce Swifts, "Chimney Swallow." Caprimulgidce Night hawk, Whip-poor-will. Coraciidce R.oller. HALCYONES Alcedinidce Kingfisher. MomotidcB Motmots. BUCEROTES Bucerotidce Hornbill. TROGONES Trogonidce Trogons. SCANSORES Picidce Woodpeckers. Rhamphastidre Toucans. Capitonidce Barbets. COCCYGES Cuculidce Cuckoos. Musophagidce Touracous. PSITTACI Loriidce Lories, Lorikeets. Cacatuidce Cockatoos. Psittacidce Macaws, Conures, Amazons, Parrots, Parrakeets. Striges Strigidce Barn-owl. Buhonidce All other owls. ACCIPITRES Falconidce Buzzards, Hawks, Falcons, Eagles, Etc. Serpentaridce Secretary Vulture. Catharidie Vultures. COLUMB^ Treronidw Fruit pigeons. Columbidce All other pigeons and doves. Pterocletes Pteroclidce Sand grouse. Gaxli Tetraonidce Grouse, Ptarmigans. PhasianidcB Pheasants, Fowls, Tiirkeys, Quail, Etc. Cracidoe Curassows, Guans, Etc. Megapodidce Brush turkey. 46 DISEASE IN WILD MAMMALS AND BIRDS Hemipodii TumicidcB Hemipodes. FULICARI^ RallidcB Rails, Porphyrios, Gallinules, Coots, Etc- Alectobides ArartiidCB Courlan. EurypygidoB Sun bittern. Qruidce Cranes. Cariamidce Cariama " Crane." Psophiidae Trumpeters. LlMICOL^ (Edicnomidce Thicknees. CharadriidcE Plovers, Sandpipers, Curlews, Woodcocks, Etc. CJiionidce Sheathbills. Gavle La/riidcB Gulls, Terns. StercorariidcB Jaeger Gull. Pygopodes Colymbidw Loons, Grebs. Alcidce Auks, Murrs, Puffins. Impenues SphenisddcB Penguins. Steganopodes SitlidcB Gannets. Pelicanidoe Pelicans. Phalacrocoracidce . . . .Cormorants. AnhingidcB Darter " Water turkeys." TUBINAEES Procellariidoe Petrels, Fulmars. Hebodiones Ardeidce Herons, Bitterns, Egrets. Ciconiido} Storks, Ibises. Plataleiidce Spoonbills. Odontogloss.^;: Ph