PART 1

.—PHARYNX, ESOPHAGUS, STOMACH AND INTESTINES

The portion of the anatomy that we now approach varies in construction almost as much through the animal kingdom as do the external shape and covering of the various orders and much more than do the other systems. The reason for this is obvious, an arrangement accommodative to the differing food chiefly, but not a little to the ease with which animals obtain and assimilate their nutriment. It would be impracticable to describe all the variations of the orders discussed in this study, but since certain gross and minute differences are of importance in comparative pathology they will be discussed at the appropriate places. It is my purpose to present in a subsequent section a discussion of food in captivity from the standpoint of its quality and quantity in relation to pathology.

Doubtless the quality of food is the largest factor in the production of disease both of the alimentary tract and elsewhere, but I am not at all sure that the quantity may not be equally important, in certain groups at least. Thus, for example, the ungulate has nearly always available in bedding a substance that he can and will eat, and the prevalent idea that an animal will eat only as much as is good for him seems not to hold at all times, since overfilled rumens are only too common. It might be thought, however, that captivity creates a sort of pica, or that enforced idleness is conducive to gorging. The use a few lines above of the word “doubtless” may have arrested the attention of some, yet when the whole subject is reviewed it seems entirely justified. Plimmer puts incorrect food at the head of the list of the causes of enteritis, Brooks emphasizes the importance of certain grasses and musty fodder, systematic writers detail among the principal causes of gastritis spoiled food, and in zoological gardens specific disease like hog cholera and enterohepatitis are relatively uncommon while nonspecific gastroenteritis is the most frequent diagnosis in causes of death.

The other factors to which enteritis is ascribed are animal and vegetable parasites and mechanically operative foreign bodies, the last being unimportant. Just how important the first mentioned are is a matter of some question which must be subjected to considerable study before any solution can be expected.

If for no other reason than that the gross and minute pathological anatomy of gastroenterocolitis is the same through the mammals and birds (aside from a few specific lesions like enterohepatitis, typhoid fever, etc.), while the food and bacteria vary, it would seem probable that the ultimate cause is the same, a poison which can be formed alike in the carnivorous and herbivorous gut, and not dependent upon bacteria, but upon the chemistry of the food or of the intestinal mucosa. To put the matter more simply, the lesions being the same under nearly all conditions is not the cause the same, and is it not a poisonous product from food or the intestinal lining. It is profitable here only to mention the marked similarity of enteric lesions under the differing conditions and in different orders. We shall study chartwise, the various forms of inflammation from the cardia to the anus in terms of their anatomical diagnosis and most probable etiology in an attempt to throw light upon the matter, and later present the physiology. System requires, however, some attention first to anatomical order so that a brief review of the esophageal and pharyngeal conditions is indicated.

PHARYNX.

The buccal-pharyngeal cavity in mammals is used chiefly as a passage way for food and as the place where some of them triturate and insalivate the bolus. Certain orders, Primates, rodents and marsupials, use this cavity thoroughly at the first mastication, others use it little at first but may ruminate, the ungulates, while strict carnivores use it very little. The Aves use their pharynx almost exclusively as a passage, and, despite the presence of a certain amount of salivary gland tissue, probably do not digest any substance in this cavity. The crop or ingluvies is a sac to permit of salivary digestion but is really a storehouse to allow rapid feeding without overfilling of the proventricle. The esophagus extends from the pharynx to the cardiac opening of the stomach in mammals and widens into the glandular stomach or proventricle in birds, the upper end of which lies in front of the lower third of the left lung behind the heart.

Inflammations of the buccal, pharyngeal and esophageal walls are relatively common in certain orders especially ground birds and grazing ungulates. This would seem to be explained on the basis of injury to the mucosa by sharp or pointed objects picked up while feeding. The character is usually necrotizing, but need not be, and the bacteriology is not specific. Definite infectious diseases like diphtheria and actinomycosis are not included here, but it might be mentioned that the second disease cited is believed to be started by the penetration of the organisms into wounds made by sharp grasses. Certain orders, notably Ungulata, Passeres, Psittaci and Struthiones, are quite susceptible to mycotic infestation and we have seen an outbreak of thrush in Kites (Accipitres). It is, however, interesting and possibly significant of peculiar protective powers in the upper alimentary tract, that strict carnivores have failed to show ulcerative, purulent or necrotizing inflammations of the mucosa from the mouth to the cardia. There has been no important data upon ingluveal indigestion or esophageal obstruction. Birds especially, and occasionally mammals, gorge themselves or take too large a bolus, but it seems as if this is only fatal where some distinct important pathology is present which has reduced their resistance. In the lower esophagus one has to deal with worms in connection with the proventricle in birds, but no mammals seem to have suffered with temporary or permanent strictures. “Crop-binding” has occurred in the following orders: Psittaci, Galli; and overfilling of the esophageal dilatation was seen in Accipitres and Herodiones; Columbidæ with their double crop were not affected by this abnormal collection of food in the esophagus.

DILATATIONS OF ESOPHAGUS.

The mammals have shown three dilatations of the esophagus interesting enough to detail briefly:

Mongoose Lemur (_Lemur mongoz_) ♂ . Sacculo-fusiform dilatation of esophagus, probably congenital, with adjacent fibrosis of lung. In poor condition for several years but recovered satisfactorily from a bad cut inflicted by cage-mates. At autopsy the general condition is poor, hair missing in spots, all skin dry and atrophic with patches of keratotic dermatitis. All tissues anemic, muscles lusterless. Right lung collapsed, brown and pink, spotted with anthracosis. Left lung pushed forward and to left by a mass in the posterior mediastinum. Lower lobe in its posterior portion is adherent to esophageal mass. Lower half of this lobe beginning where bronchus ends and extending over anterior-posterior surfaces shows marked fibrotic processes and at one point in tissue between end of bronchus and adherent esophagus there is no lung tissue remaining. No recent consolidations. Bronchial lymph nodes, small, firm homogeneous pale brown with specks of anthracosis. Heart contracted, normal in size, firm red-brown. Aorta is firmly adherent to esophageal mass where bronchus crosses it. The lower half of the esophageal from the hilum of the lung to the cardia is the seat of a dilatation, fusiform for the most part, but with a saccular portion anteriorly. This latter presses the left bronchus upward and heart forward. The wall of the tube is slightly irregularly thickened but there is no cicatrix and mucosa shows slight hypertrophic condition. A large mass of food occupies the dilatation. Stomach is empty save for gas. Mucosa is soft, smooth, pale pink. Duodenum shows slight swelling of the rather pale yellow submucosa and mucosa, but the tips of the villi are injected. Intestine contains only a little slimy mucus. Large intestine contains a mass of constipated feces. The esophageal dilatation seems to have been congenital although it is barely possible that the fibrosing pneumonitis and pleuritis may have aided and caused it by traction. It has been doubtless the cause of the animal’s inanition.

Black Bear ♂ (_Ursus americanus_). Sacculate dilatation of esophagus with chronic esophagitis. Chronic hypertrophic gastritis. Chronic lymphadenitis. Fatty degeneration of liver. Acute catarrhal enteritis. Had been vomiting more or less, nearly every day for two months and did not eat for six days before death. Mouth, pharynx and esophagus are full of macerated, unrecognizable food. Pharynx seems normal. Larynx is yellow, mucosa rough and slightly thickened in places especially just above the vocal chords. No excess of mucus. Esophagus in neck is dilated. Mucosa is rough, irregular yellow brown. This dilatation proceeds downward so that at thoracic opening tube is twice normal size. Upon entering thorax this dilatation turns to right and in irregular saccular form extends to diaphragm compressing heart and lungs to left. The main course of it then recrosses the midline, aorta being slightly twisted as it regains position in front of vertebræ. The wall is irregularly thickened from pseudomembranous patches and some hypertrophy of mucous and submucous layers. Muscle and serous coats are considerably thinned. The sac is full of macerated food and gas. The right lung is compressed small resilient red gray. No adhesions in either pleura. On section the lung tissue is found to be slightly edematous, red gray, compact and while not atelectatic yet crepitates much less than normal. Left lung is the seat of passive congestion in lower lobe and lower half of upper lobe. The upper half of lobe is compressed and subcrepitant like the right lung. Lymph glands of neck and thorax are much enlarged firm with large irregular, clear outlined follicles and brown firm homogeneous pulp. The aorta shows slight roughening, the intima being smooth and homogeneous.

Lion ♂ (_Felis leo_). Ten and one-half months old. Cystic parenchymatous goitre, dilatation of esophagus, ulcerative enteritis. Acute glomerular nephritis. Chronic hyperplasia of spleen. Fatty infiltration of liver. Bronchopneumonia (from pressure of goitre). Ascaris in intestines. Had lump on neck for several weeks, ate very little and seemed to have hard work to get anything down. Stopped eating toward the last and vomited water and foam. There is a small ulcer with everted lips just below left incisor on lower lip which the keeper says is of several months’ duration. The thyroid is much enlarged and forms a large mass in the upper chest and extends far up in the neck. Because of this mass the lungs are pushed far down in the chest. Heart also lies very low. The thyroids are enormously enlarged and cystic, the right measuring 13 × 8.5 × 5 cm. and the left 19 × 9 × 5 cm. The lungs are pale pinkish white. Air content increased in places, decreased in others. No hypostatic congestion. The lungs seem normal except at the apex where they are collapsed probably from pressure on lung by enlarged thyroid which dips down into the chest for at least three inches filling entirely the apex of the chest. One bronchial lymph gland was about the size of a walnut, the rest were normal. The heart seems normal except for its slightly low position. The abdomen contains about 300 c.c. of deep yellow highly albuminous fluid. No adhesions. The liver is softer than normal, glistening, smooth, moist and very yellow particularly at the edges. The gall- bladder contains a green mucoid bile and the duct is patulous. Spleen and kidneys are normal. Mouth and pharynx are normal. The esophagus is much dilated above the thyroid. The enlarged thyroid pressing upon it, has acted as a distinct obstruction. In this pouch was a large amount of food probably (from the history) eaten two days before. The esophagus below this point was normal except for the presence of thin mucus. Stomach empty save for two small bits of meat. The duodenal walls are much thickened, mucosa covered with small ulcers many with a hemorrhagic base; there were present also a few small, round worms.

[Illustration:

FIG. 14.—DILATATION OF ESOPHAGUS. LION (FELIS LEO). DILATATION PROBABLY DUE TO OBSTRUCTION BY ENLARGED THYROID BODY. IN ILLUSTRATION DISTENTION OF ESOPHAGUS CAN BE SEEN IN THE FORK OF THE THYROID LOBES. ]

Here are presented three different dilatations, the first probably congenitally started and aided by pulmonary fibrosis, therefore secondarily a traction diverticulum, the second probably entirely congenital, and the unusual third case due to obstruction by an enlarged thyroid. In this connection might be mentioned small saccular diverticula in the proventricle of a Fire Finch (_Lagonosticta senegala_), and at the pylorus in a Puma (_Felis concolor_). Neither of these seemed of any significance and played no part in the death of the animals; they did not seem to be artificially produced, by worms, for example.

THE PROVENTRICLE.

The proventricle or forestomach of birds, is the seat of active secretion of the gastric juice in nearly all orders, although Jobert believes that the mucosa of the gizzard may contribute some digestive fluid, and there are active glands in this tissue in a few orders. The proventricle does not act as a reservoir during digestion, but as soon as the juices are well mixed with the bolus the food is passed on to the gizzard. The organ has a rather free position, at least as far as its left lateral and downward movements are concerned for the left lateral abdominal air sac is free on that side of the gastric complex and the left lateral thoracic also extends down the side of the proventricle. Upward and anteriorly is the heart. Some of the cases of proventricular spiropteriasis have shown very marked congestion of the left lung, possibly due to the closure of the anteroinferior air sac aperture on that side. Aside from parasitism, affections of this organ are not very numerous.

Infestation with spiroptera and with less dangerous worms was quite serious at one time, but since routine examinations of all suspicious birds has been practiced this parasitism has been under control. This is a subject of especial importance to collections, and will be described in a special section. The susceptibility of the proventricle to damage seems from our figures to be very distinctly a matter of zoological order. In so far as parasites are concerned, the parrot group stands away ahead of all others having an incidence among autopsies upon Psittaci of 16 per cent.; after them come the Picariæ with 9 per cent., and Columbæ and Passeres each with 4 per cent. When, however, non- verminous conditions are reviewed the anserine birds are found the most susceptible, 3 per cent. of the autopsies upon this order revealing proventricular lesions; after them come the Columbæ, 2 per cent., and Psittaci, 1.5 per cent. In this group are included inflammations of all kinds, dilatations and distentions and some lesser matters.

This part of the stomach has been involved in our cases of fowl diphtheria, showing a distinct mucopurulent inflammation with penetration into the depths of the glands; no separation of the mucosa occurred, but ulceration was seen. Perforation was observed thrice, twice by ulceration around a worm while it was boring into the muscular layer and once, in an ostrich, by the penetration of a nail. Obstruction of this division of the stomach by impaction of food and stones is not common, but does occur. The reason for such obstruction is usually very obscure. Sometimes it seems due to the feeding of seeds and the like in too finely divided form, whereby food and pebbles are taken up together. Some of the smaller birds have had in times past too many small pebbles in the cages, while others have had too large seeds, thus apparently trying to use the pebbles to crush them. It would seem also that the birds had really eaten too much and could not accommodate it in the gullet and gizzard; this seems surely true in three or four Accipitres. Most often, however, we have had to fall back upon the inadequate explanation of pica or perverted appetite.

Impacted proventricles and gizzards have been observed thirty-four times, in eight of which it seemed the sole cause of death, and therefore probably entirely due to foreign bodies in food. The theory is accepted that dilatation and obstruction will not occur if the motor power of the gastric wall be normal and no inflammation exist. In this regard we can only discover five birds (the mammals will be discussed later) with any distinct inflammatory or degenerative disease of this part of the anatomy and two with lesions elsewhere which might affect the musculature; this leaves the vast majority of gastric obstruction in birds unexplained on basis of defective motor power, therefore probably dependent upon the character of material consumed. The anserine birds and parrots are most often affected by this form of obstruction.

Acute or chronic dilatation of the forestomach and gizzard is very rare in birds, it having occurred only thrice in our records, a finch, a parrot and an owl; the causes were entirely unknown since the cavities were not overfilled with food.

THE STOMACH.

Impaction of the mammalian stomach is a diagnosis made but once in our records, an Indian Antelope (_Antilope cervicapra_), and this is viewed with suspicion. The rumen was undoubtedly tightly packed, being distended to its fullest capacity with rather dry and not properly softened grain. However, postmortem changes had advanced and therefore observations in the whole body were not dependable. The bulk of food which can be accommodated by the rumen is very large, and had this not been dry and firm the condition might not have been interpreted so seriously. Many animals come to autopsy with a well filled, indeed even with a well packed stomach, but there is usually sufficient reason for this or there is distinct pathology to account for death.

All this of course implies a stomach of normal or approximately normal dimensions since distention beyond this, or dilatation of the stomach, is more definite. In veterinary medicine, gastric tympanites (rumen alone or all stomachs, or the simple stomach) is ascribed to food that ferments easily when taken in excess or in the presence of defective motor power, to constrictions by scars and to obstructive tumors; excessive feeding is sometimes mentioned but given a subordinate rôle. Our records throw very little light upon the subject since only five cases were observed. Four of these five seem to be due to acute fermentation independent of gross physical obstruction, while one, a Cape Hunting Dog (_Lycaon pictus_) showed an old chronic ulcerative gastritis with both healed and active ulcers distorting the pyloric end of the organ. Three of the first mentioned four were monkeys and one was an ocelot. The stomach of the voracious monkey is at time of dissection usually well filled, but in these cases there seems no doubt that gas and excess fluid had distended the cavity enormously, in one instance apparently assisting in acute cardiac dilatation. There were no obvious reasons for assuming any damage to the gastric motor mechanism.

[Illustration:

FIG. 15.—ROUND ULCERS IN STOMACH WALL. COMMON OPOSSUM (DIDELPHYS VIRGINIANUS). THERE IS GENERAL MODERATE CHRONIC GASTRITIS WITH ROUND ULCERS NEAR THE CARDIA. ]

GASTRIC ULCERS.

Gastric ulcer, so-called peptic or round ulcer of the stomach, having a chronic course and leading to radiating scars of the mucosa is not common in the lower animals, but frequent enough in the human being. The form of ulcer in question has at present no adequate explanation, or at least there is no one cause which will answer for all cases. Local injuries from within or without the stomach, bacterial embolism, entrance of bile through the open pylorus and many other factors have been named in the causation but can seldom be used in any given case. In the lower animals with their relatively frequent parasitic infestation, another factor is added. In analysis of our statistics I have separated ulcerative gastritis from parasitic and mycotic ulcerations and from peptic ulcers; the first is discussed in later paragraphs. Parasitic ulcers of the stomach occur chiefly in our native marsupial, the opossum, and in some Carnivora; physaloptera, strongylus, ascaris, and gastrophilus have been found. The kangaroos are frequently affected (8 cases) with an acute or subacute ulceration of the gastric wall, without much general gastritis. The lesion is peculiar in appearance. The youngest ulcers are black or dark gray, flat necroses of the mucosa alone and indeed the process very frequently penetrates no deeper. Older lesions spread laterally and may be preceded by a very narrow congested line but there is no raised edge nor does there seem to be submucous infiltration. If the process be rapid a loose dirty slough may form. Certain of the advanced cases of Kangaroo mycosis will present more infiltrative lesions of the gastric wall leading to large and well defined necrotic areas; they may at times penetrate the whole wall outward. (See page 580.)

True peptic ulcers have been found in Primates, 4; Carnivora, 5; Pinnipedia, 2; Insectivora, Ungulata and Hyraces each one. The London Garden reports that gastric ulcerations occur most often in Carnivora and Marsupialia. Those in the last three orders of our list were small, usually multiple and relatively superficial. The ulcers found in Primates and Carnivora present the usual pictures seen in man. In one example in each of these orders radiating scars of healed defects are mentioned in the notes. None of them seems to have led to cancer, and in only one, a wolf (_Canis lupus_), was the scar tissue sufficient to cause definite impediment to the motility of the stomach. Six of the fourteen examples appeared on the greater curvature, the remainder on the lesser. Ten ulcers were in the pyloric division, the other four being scattered. No other pathology is found common to these cases which might be drawn into etiological association.

TUMORS.

Tumors of the gastric complex are not at all common, there being only the following to report: Primates, Hamadryas Baboon (_Papio hamadryas_), diffuse adenoma; (none in Carnivora with the most ulcers); Marsupialia, Red Kangaroo (_Macropus rufus_), malignant papilloma with metastases. The former tumor, shown in Fig. 17, was a diffuse soft excrescence beginning near the pylorus and stretching along the lesser curvature toward the cardia. Histologically it was made up of glandular acini growing in all directions but always maintaining normal relations of cells and basement membrane. There were no metastases and other reasons for death existed. The tumor of the kangaroo stomach was a true epitheliomatous cancer with metastases to liver, spleen, and kidney. Only one secondary tumor was observed, from a carcinoma of the lung in a Red Kangaroo (_Macropus rufus_).

[Illustration:

FIG. 16.—MULTIPLE GASTRIC ULCERS. COMMON WOLF (CANIS LUPUS). CHRONIC GASTRITIS WITH NUMEROUS IRREGULAR ULCERS OF THE PEPTIC TYPE. ]

[Illustration:

FIG. 17.—PAPILLOMA OF STOMACH. HAMADRYAS BABOON (PAPIO HAMADRYAS). ]

THE INTESTINE.

Inflammation of the gastrointestinocolic tube is the most important single condition with which handlers of animals have to deal, and unfortunately it can seldom be diagnosed clinically, early and accurately enough, to make treatment useful. At this Garden some evidence of acute or chronic disease of the tube has been present in 31 per cent. of our autopsies. The reports of other gardens would indicate that their figures might be quite close to this. What is the cause of this high mortality? Incorrect feeding, qualitatively or quantitatively has been put at the top of the list by Plimmer, but he adds other less important factors: Bacteria of infectious power, protozoa, foreign bodies and parasites or their mural cysts. In order to evaluate approximately how each of these acts let us review the causes as they are generally known and later discuss the pathology as seen in the various orders.

(1) Overloading of the stomach by too much food or by rapid eating of a hungry animal is of importance under certain domestic circumstances where times of feeding are irregular or intervals are too long, but this cannot occur in any well regulated menagerie. It is possible, however, that overfilling might occur in certain Ungulata, which have hay and straw nearly always available, if the food in their reach happens to be particularly agreeable or tasty to them.

(2) Insufficient mastication would seem to be important only in those orders which depend upon this action to triturate, insalivate and macerate their food, of which Homo, Primates, Ungulata and Marsupialia are the principal ones.

(3) Disturbance during and after feeding has always been believed to affect digestion unfavorably, and it may be that visitors to a collection exert such an effect; this factor is probably negligible.

(4) The appropriateness of the food is a very important factor in the health of an animal under captive conditions. Diet lists are made up by officials largely according to the known habits and general physiology of an animal, but the food offered can at best only approximate what the wild beast obtains for himself. It does not follow because a selected diet may seem to provide all the elements contained in the food available under natural conditions that it actually does so, especially since we are aware that some essential food factors, known under the term vitamins, are necessary to best development. These substances vary in closely similar foods, and seem to be higher in simple natural foods than in prepared diets. We have seen in this Garden that the inorganic constituents must be correctly represented in the food, else degenerative osseous condition may develop. Inappropriate diet may express itself at once after the receipt of an animal, by its sickness or death, or after some time in the development of chronic tympanites, chronic intestinal catarrh or bony deformities.

(5) The physical condition of food is a matter of no small moment. The taking of soft food in large quantities especially by herbivorous animals, permits too short a sojourn in the gastric fundus and is often followed by pyloric and duodenal disease. Too firm food may pack the rumen, fundus or proventricle as the case may be, and be succeeded by distention of these parts and catarrh of the pyloric and intestinal area. The effect of foreign bodies mixed with food is difficult to evaluate unless of course they be of such a nature (pointed metal and the like) as directly to traumatize the mucosa. Many birds and mammals come to autopsy with a relatively large number of stones and small sticks in the stomach without any distinct evidence that they have been hurt thereby. In the bird the stones may be so large and numerous as to leave little room for food, or small enough to pass out into the intestine where they undoubtedly may pave the way for bacterial action. Smoothly polished pebbles in small quantity seem to have little effect in mammals. Hair balls are not common and unless of large size are apparently unimportant. Considerable sand mixed with food has a distinctly irritating effect. It is perhaps best known as a chronic gastric disorder of horses; we have seen it in zebra.

(6) Spoiled food is obviously a very prime factor in inflammations of the gastrointestinal tract. Its operations are illy understood except perhaps when products of fermentation or putrefaction prevent digestive action or are absorbed. If in small quantities not sufficient to cause acute fermentative inflammation or intoxication, such substances frequently taken may doubtless produce chronic catarrhs. Many animals are fed upon vegetable mashes, or stews which can decompose, while bad meat may occasionally be fed. We had a rather serious outbreak of enteritis in small Carnivora from the use of fowl heads obtained at hotels; some of these cases were shown to be due to B. paracoli, thus to be looked upon as infections. Dirty food while not spoiled may carry with it organisms of decomposition, or of infective qualities, or the dirt may act as an irritative foreign body. We have found that for delicate ungulates (antelopes) it is highly desirable to screen grain, and that the grade of hay should be of the best.

(7) Infectious conditions are of great importance under certain circumstances but with the exception of hog and fowl cholera, the dysenteries and a few other diseases, do not as a rule play a great part in mortality as specific diseases unless of course an epizoötic appear. The greater problem is to understand bacterial action in the face of other factors. Are infectious germs introduced with food and drink in every case of gastroenteritis or do some other factors activate those already present in the gut tract? Unfortunately these questions cannot be answered directly. We can, however, point out which groups of bacteria are most common in some of the orders, which orders are most susceptible to bacterial invasion and which to local lesions with intoxication. The greatest problem in the field is the interrelation of germs of various sorts in the intestinal tract. Certain varieties are known to develop intoxicating aromatic substances, others to elaborate or excrete fatty acids, still others to form antiferments but the conditions existing in the various kinds of intestinal tracts are too little understood to help very much in this study.

(8) Animal parasites have long been considered as one of the causes of gastrointestinal inflammation, a condition largely due to copying from book to book of a few facts and more impressions. The sum of reliable information to-day would seem to indicate that a few parasites—uncinaria being the most conspicuous example of this type—draw considerable blood from the mucosa, that a few, like uncinaria and dibothriocephalus, elaborate an absorbable toxin, that some, notably ascarids, produce an irritating substance, and that many possess the power in themselves or by some excretion to act as antiferments. These factors, were they all combined in one worm, might probably irritate the mucosa sufficiently to produce inflammation, but it is not easy to imagine that they would cause an acute specific condition. It is much more easily conceived that with tiny hemorrhages or ulcerations of mucosæ, bacteria might get in their work or if considerable ferment were neutralized, maldigestion, flatulence or indigestive irritation would ensue. With certain worms like esophagostomum there is considerable evidence to show that a chronic fibrous disease of the intestinal wall arises, but in this case the parasite resides in the mucosa and acts as a foreign body. It would seem, however, that the most important influence that animal parasites exert is to be found in the preparation of the mucosa for the action of bacteria. Masses of parasites may of course physically obstruct the lumen and lead to intestinal stasis and dilatation.

INFLAMMATION.

In analyzing the cause of a gastroenteritis and its consequent effect upon the wall of the tube and upon the viscera, certain physical, chemical and physiological factors must be considered. Whether this may be directly the effect of bacteria or poisons from worms or some other factor seems of little moment since in any fully developed case, symptoms and effects are comparable. Moreover it seems that pathological anatomy, both gross and minute, is essentially the same from Primates to struthious birds, the highest and lowest of the two classes here considered. By this is meant that the acute congestive condition of the gut tract with solution of the surface, to which we have applied the name of toxic enteritis, seems to be met with in this form throughout all the orders. So too catarrhal inflammations are the same to the naked eye and under the microscope, due allowance being made for the fact that mammals use polynuclear cells for exudative purposes while birds employ mononuclears. Concomitantly with these conditions, a degenerative process may be going on in the liver and kidney, and hyperplasias, especially in the true infective processes, will be found in the related lymphatic structures.

The majority of students to-day place responsibility for gastroenteritis upon the bacteria known to be present in the various intestinal tracts, mentioning especially colon and proteus groups, streptococci, the necrosis bacillus and anaerobes of the Welch class. In a few of our studies of intestinal bacteria in cases of enteritis one thing has been very definite and that is that in the intestinal content of animals whose food is largely meat, Gram-negative bacilli have predominated, whereas in herbivorous animals Gram-positive organisms have been most numerous. From the observations of Kitt, Strassberger and some others, the normal flora of domesticated animals is subject to wide variations so that our observations must receive confirmation before they are finally acceptable. We have on several occasions isolated from carnivorous intestines Bact. paracoli, Bact. suipestifer and other members of this group. We have no reliable cultural data upon the herbivorous intestine and can only quote the Gram pictures as mentioned above. On two occasions, an eland and an elk, a very large number of forms corresponding to necrosis bacillus were seen; to this organism Kitt gives considerable power in the production of necrotizing processes.

TABLE 11.

_This table shows an analysis of all cases of gastroenterocolitis. The left half of the table is an analysis of orders upon which one hundred or more autopsies have been done, the right half of orders with fewer than that number. The left half is expressed in percentages, the right half in number of cases only since percentages might be misleading. Left hand table: First column is percentage of gastroenterocolitis per order; next five columns the percentages in which each of the factors in the headings was believed responsible; the last three columns show the participation of each of the divisions of the intestinal tract; thus Primates had all told 24.8 per cent. of inflammations of which 7.2 per cent. were in stomach, 18.3 per cent. in the intestines and 8 per cent. in the colon; obviously many had all three sections affected. Right hand table is constructed on a similar basis except that number of cases is quoted, not percentages, and the total is put in the last column._

════════════╤═══════════════════════════════════════════════════════ │ Percentages in orders with sufficient autopsies. ────────────┼─────────┬────┬────────┬─────────┬────────┬──────────── │Per cent.│Food│Bacteria│ Animal │Physical│Undetermined │ of │ │ │Parasites│Objects │ │Autopsies│ │ │ │ │ ────────────┼─────────┼────┼────────┼─────────┼────────┼──────────── Primates │ 24.8│ 1.8│ 4.4│ 3.6│ │ 15. Lemures │ │ │ │ │ │ Carnivora │ 46.1│ 2.9│ 7.2│ 5.8│ .2│ 30. Pinnipedia │ │ │ │ │ │ Insectivora │ │ │ │ │ │ Chiroptera │ │ │ │ │ │ Rodentia │ 25.│ 5.│ 2.│ 2.│ │ 16. Ungulata │ 24.8│ 6.6│ 2.2│ 2.│ .8│ 13.2 Proboscidea │ │ │ │ │ │ Hyraces │ │ │ │ │ │ Edentata │ │ │ │ │ │ Marsupialia │ 33.1│ │ 10.│ 10.1│ │ 13. Passeres │ 23.6│ .1│ 4.5│ 1.8│ .15│ 17. Picariæ │ │ │ │ │ │ Striges │ 41.5│ 1.5│ 5.3│ .7│ │ 34. Psittaci │ 36.6│ .3│ 10.7│ 3.7│ .15│ 21.8 Accipitres │ 40.7│ │ 4.5│ │ .5│ 35.7 Columbæ │ 17.8│ │ .6│ 3.│ .6│ 13.5 Galli │ 38.6│ │ 5.3│ 19.6│ │ 13.7 Hemipodii │ │ │ │ │ │ Fulicariæ │ │ │ │ │ │ Alectorides │ │ │ │ │ │ Limicolæ │ │ │ │ │ │ Gaviæ │ │ │ │ │ │ Impennes │ │ │ │ │ │ Steganopodes│ │ │ │ │ │ Herodiones │ │ │ │ │ │ Odontoglossæ│ │ │ │ │ │ Palamedes │ │ │ │ │ │ Anseres │ 29.6│ .3│ 4.4│ 2.3│ .6│ 22. Struthiones │ │ │ │ │ │ Crypturi │ │ │ │ │ │ ────────────┴─────────┴────┴────────┴─────────┴────────┴────────────

════════════╤════════════════════════╤════════════════════════════════ │sufficient autopsies. │Number of cases in orders with under 100 autopsies each. ────────────┼───────┬──────────┬─────┼────┬────────┬─────────┬──────── │Stomach│Intestines│Colon│ │Bacteria│ Animal │Physical │ │ │ │Food│ │Parasites│Objects │ │ │ │ │ │ │ ────────────┼───────┼──────────┼─────┼────┼────────┼─────────┼──────── Primates │ 7.2│ 18.3│ 8.│ │ │ │ Lemures │ │ │ │ │ 8│ 2│ Carnivora │ 21.│ 41.│ 6.6│ │ │ │ Pinnipedia │ │ │ │ │ 1│ 1│ 1 Insectivora │ │ │ │ │ │ │ Chiroptera │ │ │ │ │ │ │ Rodentia │ 7.│ 20.5│ 3.5│ │ │ │ Ungulata │ 9.1│ 20.│ 2.5│ │ │ │ Proboscidea │ │ │ │ │ │ │ Hyraces │ │ │ │ │ │ │ Edentata │ │ │ │ │ │ │ Marsupialia │ 22.│ 21.│ 3.5│ │ │ │ Passeres │ 1.2│ 22.│ 3.│ │ │ │ Picariæ │ │ │ │ 1│ 10│ 4│ Striges │ 6.│ 40.│ .7│ │ │ │ Psittaci │ 1.7│ 35.4│ 1.3│ │ │ │ Accipitres │ 5.2│ 39.│ 1.│ │ │ │ Columbæ │ 4.5│ 13.5│ .7│ │ │ │ Galli │ 2.6│ 21.6│ 19.6│ │ │ │ Hemipodii │ │ │ │ │ │ │ Fulicariæ │ │ │ │ │ 6│ 1│ Alectorides │ │ │ │ 1│ 1│ 2│ Limicolæ │ │ │ │ │ │ │ Gaviæ │ │ │ │ │ 1│ 1│ Impennes │ │ │ │ │ │ │ Steganopodes│ │ │ │ 1│ 1│ │ Herodiones │ │ │ │ │ 1│ 3│ Odontoglossæ│ │ │ │ │ │ │ Palamedes │ │ │ │ │ │ │ Anseres │ 2.5│ 27.7│ 6.6│ │ │ │ Struthiones │ │ │ │ │ 7│ │ Crypturi │ │ │ │ │ │ │ ────────────┴───────┴──────────┴─────┴────┴────────┴─────────┴────────

════════════╤═════════════════════════════════════════════════════ │Number of cases in orders with under 100 autopsies each. ────────────┼────────────┬───────┬──────────┬─────┬─────────────── │Undetermined│Stomach│Intestines│Colon│ Total Animals │ │ │ │ │ Showing │ │ │ │ │Gastroenteritis ────────────┼────────────┼───────┼──────────┼─────┼─────────────── Primates │ │ │ │ │ Lemures │ 13│ 4│ 19│ 3│ 23 Carnivora │ │ │ │ │ Pinnipedia │ 8│ 7│ 8│ 1│ 11 Insectivora │ │ │ │ │ Chiroptera │ 2│ 1│ 1│ │ 2 Rodentia │ │ │ │ │ Ungulata │ │ │ │ │ Proboscidea │ 1│ │ 1│ │ 1 Hyraces │ 2│ │ 1│ 1│ 2 Edentata │ 2│ │ 1│ 1│ 2 Marsupialia │ │ │ │ │ Passeres │ │ │ │ │ Picariæ │ 24│ 5│ 36│ │ 39 Striges │ │ │ │ │ Psittaci │ │ │ │ │ Accipitres │ │ │ │ │ Columbæ │ │ │ │ │ Galli │ │ │ │ │ Hemipodii │ │ │ │ │ Fulicariæ │ 8│ 1│ 15│ │ 15 Alectorides │ 10│ 2│ 13│ 3│ 14 Limicolæ │ 1│ │ 1│ │ 1 Gaviæ │ │ │ 2│ │ 2 Impennes │ 3│ 1│ 3│ │ 3 Steganopodes│ 8│ 1│ 10│ │ 10 Herodiones │ 25│ 1│ 24│ 6│ 29 Odontoglossæ│ │ │ │ │ Palamedes │ 1│ │ 1│ │ 1 Anseres │ │ │ │ │ Struthiones │ 14│ 8│ 20│ 3│ 21 Crypturi │ 1│ │ 1│ │ 1 ────────────┴────────────┴───────┴──────────┴─────┴───────────────

THE TABLE.

Our records have been analyzed from the standpoint of diagnosis and the most probable cause. The first will be taken up in discussing each of the orders. The probable causes are divided into food, bacteria, animal parasites, physical objects and undecided, in other words a classification based upon the most prominent or definite evidences as seen at postmortem combined when possible with antemortem observations. When findings were inconclusive or contradictory, cases were called undecided, naturally a very large group. Fermentative processes in the presence of obviously undigestible material, are classified with food as a cause. When evidences of septicemia existed in absence of the other factors, it is held that bacteria were responsible. Cases were grouped under animal parasites when these were the most definite findings. Physical objects are relatively unimportant and self-explanatory. To the etiological chart there are appended columns intended to show the percentage or case incidence of the disease of the grosser subdivisions of the gastrointestinal tract which indicate in a general manner what part of the tube in the various orders is most susceptible to disease. While of course conclusions must be drawn with great caution, there can be little doubt, for example, that carnivores and marsupials have more gastric disease than any other order, and that the high place for the colon is held by the gallinaceous birds. This charting was suggested by the work of Dr. Raymond Pearl upon statistics, wherein he takes as a basis of classification the part of the body which succumbs to disease- producing organisms or from which a disease starts. It cannot be stated that there is a clear cut relationship between enteritis and the expectancy of life.

MAMMALIA.

The PRIMATES as an order have their share of inflammations of the gastrointestinal tract and present points of interest. Acute digestive disorders succeeded by acute dilatation of the stomach, or in less fermentative cases by acute catarrh of the intestine, are not at all uncommon. The reason for this is not discovered by reviewing the diet and manner of feeding. The buccal pouches, distensible esophagus, the freely movable stomach, and relatively elastic gastric wall would seem to permit of very considerable dilatation to accommodate the large quantities which the monkey sometimes crams into himself. Nine fairly acceptable records of gastric overfilling exist and two of them seem to have been followed by tympanites sufficient to embarrass respiration, in one case there occurring an acute cardiac dilatation with myocardial degeneration. The animals give no symptoms of this condition and in the last case cited the beast, while old, ate well and was not distended the evening before death.

When acute gastritis exists (twenty cases) the animal seems uneasy but does not vomit. On one occasion I was called to see a monkey which was retching and seemed in pain. Lime juice was offered and taken, followed by gentian and cardamon, which seemed to give some benefit. Somewhat later this was repeated in another case, but observations where this might be useful are rare.

The pathology of gastric conditions offers little to contrast with that of man. The enormous distensibility of the fundal pouch often suggests to the observer the rumen of ungulates. Acute gastritis of one kind or another and acute catarrhal enteritis are the most common lesions noted in the Primates. Involvement of the intestine or colon need not carry with it an increase of signs of illness, although at times one will see an evidently sick animal with diarrhœa. Anatomically the lesions are commonly restricted to the stretches of gut _above_ the ileum, it being rather rare that this division or the colon is affected. Pathologically the lesions are catarrhal with definite involvement of the follicles in about one-third of the cases. In this order toxic and pseudomembranous forms are quite rare and ulcerative lesions uncommon. Colonic disease as a sequel to inflammation higher up is sometimes seen in the follicular varieties, but takes a minor place compared to amœbic dysentery of which we have had several cases; this will be discussed under a separate heading. Degenerative disease of the skeleton is almost always accompanied by a low grade of enteritis but not necessarily gastritis or colitis. The pallor of the mucosa, while at times striking, may be relieved by follicular spots and petechia or pigmentation. Often, however, animals suffering from osteomalacia and rickets come to their end by an acute inflammation of the gut tract.

The bacteriology at our disposal allows no conclusions. Aside from a case probably due to Ps. fluorescens and one with colon bacillus abscesses in the liver, no reliable data are at hand.

Reference to Table 11 reveals the fact that among orders with sufficient autopsies to permit percentages, the alimentary tract in monkeys is in the group of low figures, that the intestinal section is relatively more often affected, and that the colon is more often diseased than in other mammalian orders, and is exceeded only by the gallinaceous birds.

The LEMURES, of which we have eighty-six autopsies, do not differ much in anatomy from the Primates, however greatly they disagree in habits and outward appearance; their diet is the same. Clinically the slothful behavior of a normal lemur probably obscures symptoms and signs of illness, for our antemortem notes with the exception of a few observations of loose stools, fail to offer a lead as to diagnosis. This order has a large incidence (twenty-three cases) of gastroenteric conditions as shown in Table 11, but some explanation of the figures is deserved. In the first place, only one case of acute gastritis occurred, and this was apparently a part of a general infection, and if induced at all by food this was only secondary. Indeed as one reviews the records it does not seem that the lemurs are easily disturbed in their gastric digestion. Acute and subacute inflammations from bacterial action seem definitely more prominent since they take the catarrhal, follicular and deep submucous form and are frequently associated with generalized infectious processes. One amœbic case was observed and there was another in which a heavy cestode and nematode infestation seemed to have paved the way for bacteria.

CARNIVORA.

The food of this order is received into the fundal part of the stomach, the distensible but normally capacious left and superior two-thirds of the organ. The general shape of the viscus, that of a gourd, permits a fairly sharp separation of the fundal and pyloric sections, so definite indeed that the pathology of the two parts was studied. The intestines vary in length, but in the land carnivores are relatively short, narrow in lumen and rich in wall. A cecum, or at least a blind end of the large gut made by the insertion of the small intestine above the tip of the colon, is suggested in all families, although, as in the bears, it may be quite insignificant or rudimentary. Theoretically no stasis should occur at this point. The colon is short in all carnivores and, like the small gut, with a heavy wall. The comparative simplicity of the carnivorous gut tract, the ability of many of these animals to disgorge, the suggestion of high resistance of the upper end of the tract to infection and the ease with which diarrhœa can clear out the tube, would seem to warrant the expectation that inflammation would not be serious. Such, however, is not the fact for, on the contrary, they have shown a higher incidence than any other order for which we have adequate comparison. Anatomically considered their stomach occupies the second place in vulnerability, next to the marsupials, and their intestines the highest place; this indicates of course that combined gastric and intestinal disease has often occurred. Involvement of the colon occupies the second place, in ordinate susceptibility, being exceeded only by the monkeys, due to heavy parasitic infestation, but would occupy the first place were the eleven amœbic dysenteries in monkeys subtracted from their total, a subtraction which might be allowed since it represented an epizoötic outbreak.

Etiologically considered, it would seem as if the influence of incorrect feeding were of little importance, and from one standpoint this is probably the case. Acute fermentative or irritative processes are not common at all, while more inflammatory pictures, catarrhal, erosive or ulcerative, are the rule. There is another phase to the term incorrect food, that is incorrect in its cleanness. During 1912–15 there was an increasing mortality among the cats and dogs fed upon horse meat, mutton and fowl heads. Early in 1916 the butcher shop was reconstructed and thoroughly cleaned and covered galvanized pans supplied in which to transport the food; these pans were scrubbed and scalded after use. Since that time, infections inflammations of the stomach and intestines have shown an ever increasing downward incidence, which result, there having been no material changes in other directions, I do not hesitate to ascribe to the improvement of butchering and dispensing engineered by Dr. W. B. Cadwalader.

Helminths seem to be of importance in this order both by reason of the percentage of autopsies in which they presented the most probable or at least most suggestive cause and because uncinaria and strongylus have been seen attached to the wall and a large bulk of known irritative cestodes have occupied the lumen. Physical objects, stones, bones, wire, may cause irritation enough to activate bacterial action or may actually penetrate the wall; the latter action is well known. In so far as practical application of this is concerned, it teaches to feed whole, unsplintered or ground bone.

The distribution and character of pathological lesions according to the region of the stomach is what might be expected from the shape and physiology of its parts. True inflammatory processes are best, and in some cases only seen in the pyloric half of the viscus, while the changes in those few cases believed to be fermentative or irritative in nature were largely confined to the fundus. Dilatation of the latter part may be understood because there the muscular coats are about equal to the mucous in thickness and one-half the width of those at the pylorus, but why inflammatory processes should not be so developed in the fundus is not clear unless the greater availability of mucus protects the secreting wall. Not only does acute inflammation reach its most definite form in the second part of the stomach, but the irregular pigmentation, mammillated overgrowth and atrophy or ulceration of chronic disease are likewise best seen in this part.

Acute enteritis, of all varieties, is seen more beautifully in carnivores than in any other order of mammals, and nowhere can it be studied better. Its gross appearance is that of the text-book and its minute character even more instructive. I have used a slide of acute catarrhal enteritis in a lion for the illustration of this lesion for the _Text-book of Pathology_ by Doctor Stengel and myself. However, as is known to all who have paid any attention to enteritis, the postmortem findings are usually much less definite than clinical observations would warrant one to expect. The Carnivora not uncommonly show intestinal congestion, mucous membrane swelling without edema or opacity, congestion of the spleen, cloudy swelling of the liver and kidneys and perhaps mesenteric lymph node edema. This picture we have viewed as a toxic affair of some sort or a bacterial infection not yet far enough advanced to produce catarrhal or ulcerative enteritis and septicemia. In such cases the carnivorous intestinal mucosa offers instruction. The epithelium is vacuolated or fringed on the free edge or may be missing altogether. In the depths mucus formation is very active, and where it is going on, round cells seem attracted, collecting in groups in the villus or in the subjacent submucosa. Perivascular round cell increase may be noted. Plasma cells and granular eosinophiles are common, but I cannot state how important the latter are in the general picture because of the frequency of parasites in carnivores. The central vessel of the villus and the arterioles of the submucosa are injected. Lymph follicles may or may not be enlarged, but if so usually fail to show a germ centre.

Colitis alone is not common in this order, but as an extension process or involvement at the same time as the upper levels it occurs occasionally. The only fact I wish to record and one which I would emphasize because of having seen it recently in a human case of chronic colitis, and since it does not appear important to systematic writers, is superficial blood supply. The capillary network of the colonic villi, while rich, is in the form of a fine plexus just under the epithelium. In the cases studied these vessels become quite distinct and possess much more definite walls, often bordered by mononuclears, while connective tissue is more evident at the bases of the villi and deeper. This may help in deciding the existence of a colitis.

Bacteriologically the most instructive experience to report is the discovery that a small outbreak of enteritis among small Carnivora, chiefly cats, fed upon fowl heads was due to Bact. paracoli, or at least this organism was found in the intestinal mucosa, spleen, and heart’s blood of three cases. The type of enteritis was hemorrhagic and follicular. There was also a case of septicemia apparently emanating from enteritis due to Bact. suipestifer in a lion (_Felis leo_). These facts bring strongly to attention the modern teaching that meat poisonings of the Gärtner type are to be considered as infectious and not of the so-called ptomaine group.

PINNIPEDIA, while related closely to the Carnivora, are grouped in a suborder in our classification and because of their restricted diet are treated here in a separate paragraph. The tract is peculiar in the strong tubular stomach sharply bent upon itself, the great length of the small gut (upwards of a hundred feet in some genera), and the practical absence of a cecum. Pathologically speaking, the most striking lesion of these animals is ulcerative gastritis, a process usually most marked along the posterior-superior surface, but not confined thereto. Upon inspection the gastric mucosa, normally supplied with low regular rugæ, is much distorted by swellings upon the top of which are irregular ragged ulcers with rounded elevated but not frayed margins. The density of the edges indicates much infiltration of the deep mucosa and submucosa; this can be confirmed by microscopical examination. One attempt to study this gastritis bacteriologically was fruitless. Sections of one case showed streptothrix-like masses while in another case bacterial colonies and yeast-like bodies were found in adjacent lymph nodes. The genesis of this condition might lie in injury by fish fins or by foreign bodies, of which large numbers are found at times (a pint and a half of stones, marbles, and sticks were found in one stomach). Gastritis has been the starting point of septicemia on two occasions, and three times an acute exacerbation or new implantation of infection occurred, with extension into the intestine. It is interesting that all the deaths of Pinnipedia with gastroenteric conditions occurred in the winter months.

INSECTIVORA are represented by two common European Hedgehogs. In one there were three shallow but shelving ulcers in the stomach which had bled sufficiently to weaken the animal; free blood was found in the intestine. The other specimen was diagnosed at postmortem as having catarrhal enteritis involving nearly the whole small gut, but histological section did not confirm this.

As one descends the zoological scale the first gastrointestinal tract prepared for the nutritional care of bulky food is to be found in the RODENTIA. This order presents a great variety of shapes and arrangements of the stomach, but the outstanding feature, with very few exceptions (cf. spermophiles), is the development of the cardiac and fundal divisions ostensibly for the reception of a large bulk of coarse food to be digested at leisure. Some genera like the hamster (_Cricetus_) have a stomach closely resembling the ruminants, while that of the spermophile suggests the equine stomach. The pyloric end, variable in many ways, greatly resembles the abomasum. So too the duodenum is large, loose and distensible while the copious small gut ends in a very large cecum, shaped at times in a manner which has led to the term “colonic stomach.” The colon is variable and not always supplied with longitudinal bands and sacculations.

In regard to incidence of gastrointestinal disease, rodents occupy a middle position in the table. The stomach seems a vulnerable section of the tract. Dilatation of the left hand section is common, due, to all appearances, to fermentative processes which have as a result the softening of the mucosa so that even immediately after death it will separate almost entirely. In these cases the pyloric part need not participate but may remain flat, smooth, soft and pink. This condition is slightly more common in the compound than in the simple stomachs. In some of this order, especially rats and cavies, there is a fermentative gastroenteritis expressed by injection and edema of the pylorus and duodenum, and much frothy mucus. It was at first thought that some relation might exist between this condition and the absence of the gall- bladder, but it occurs in varieties possessing this structure. The reaction of the intestine to irritation in this order is peculiar in two ways, the occurrence of mucus and the activity of the lymphatics. In all the inflammations from and including the stomach to the cecum, mucus is conspicuous. At times it is thin or loose and mixed with contents, while at others it forms a relatively close covering for the mucosa almost like a false membrane. Rodentia are peculiar in the promptness and clearness with which the follicles of the intestinal wall and mesentery enlarge in inflammation. They appear as pale, well outlined or diffuse opacities in the wall or as distinct plaques prominent on the surface.

The PROBOSCIDEA are represented by one Elephant (_Elephas indicus_), in which a mild catarrhal change was seen in the middle stretches of the small intestine. This was of little importance as a cause of death, there being several other diagnoses, and was probably a terminal affair.

HYRACES, of which we have a total of seven examples, present two mild involvements of the intestine but none of the stomach. It would appear from the records that the intestinal condition had little to do with the death of the animals, and unfortunately no microscopic slides were made. Because of the curious formation of the large gut, notes of both ceca were made in one case, and can be condensed as follows: “The upper or anterior cecum presented a shaggy pearl gray mucous covering, closely attached to the mucosa. This cavity and the posterior ceca were packed with dry crumbling feces. Small thin-walled cysts were seen in the tips of the lower ceca. Duodenum was congested and mucosa swollen. Stomach contained dry, poorly digested food. No parasites were found.”

The EDENTATA are represented by an Armadillo (_Tatu novemcinctus_) and an Anteater (_Myrmecophaga tridactyla_.) The former had a prolapse of the rectum accompanied by colitis but it is impossible to decide the priority of the two conditions since the former is known to have existed long enough to have permitted the latter to develop. The Anteater had a distinct mucocatarrhal enteritis in which bacteria played a part since involvement of the liver, spleen, kidney and lymph nodes also existed. The beast was in good condition upon arrival, but did not become accustomed to the proffered diet, and was distinctly anemic at death.

The UNGULATA, so-called for their hoofed and horned character, are also associated anatomically by the construction of their gastrointestinal tract. However, the order of the list as given on page 44 does not represent their historical development nor does it accord with anatomical arrangement of the tube under discussion. The last three families of Artiodactyla are perhaps the simplest in the construction of this tube, or at least take an equal place with the Perissodactyla, while the remaining families of the former suborder have a complex tract of generally similar architecture. This whole order has, however, an alimentary tract anatomically suited for the consumption of bulky vegetable stuffs and shows an attempt at adjustment between the food, the methods of mastication, the area of digestive surface, and the bulk necessary for nutrition. The number of factors opened up by the many variations between this complex tract and that of the carnivorous simple tract is so great that I shall attempt only to contrast the anatomy and pathology of the simpler ungulate tracts and the complex ruminant apparatus.

The simpler gastrointestinal tract is possessed by the Perissodactyla, and by the following families of Artiodactyla, the Phachocœridæ, Suidæ and Tayassuidæ. This consists of a stomach with a single cavity (some Peccaries have partitions but no true septa with strict histological differences) divided into esophageal, cardiac, fundal and pyloric areas, dependent upon the nature of the lining epithelia and the absence or presence of glands, as well as the nature of the tubules. The duodenal section is ample and may be sacculated while the intestines are small in calibre and rather sturdy in wall. The cecum is relatively very large, well supplied by longitudinal bands and sacculations; the colon is relatively short but quite capacious and sacculated.

The ruminants and other remaining members of the Artiodactyla have a compound stomach suited to the separation of coarse and fluid foods and the retention of water, and so arranged that boluses of different densities are distributed as needed. These divisions are histologically as well as grossly different. The first three, comparable to the esophageal section of the simpler stomach, are reservoirs or channels, while the fourth or true digestive section, is divided into areas corresponding to fundus and pylorus, possessing the appropriate type of gland. The duodenum in this group is narrow, as is the rest of the small gut, and has delicate walls. The cecum proper is short and of variable width, but never as great as in the group first discussed, while the colon, an intricately wound tube, is narrow and very long. Certain of the first group (Peccaries) have a colon of this type, but it is not so complicated as in true ruminants.

These complications seem designed to permit of a long retention of coarse food of low nutritive value per bulk for a time sufficient for full digestion; reverse adaptation of large size of stomach and colon may be explained on the same basis. Let us now examine these two groups to discover their pathological reactions and the nature of the lesions.

TABLE 12. _Showing the Percentage Incidence of Various Forms of Inflammation in the Alimentary Tract of Ungulata._ ══════════════════════════════════╤═════════════════╤═════════════════ Lesion │ Group A │ Group B │ Perissodactyla │ Ruminants and │ and Swine, Wart │ Relatives Per │ Hogs, Peccaries │ cent. │ Per cent. │ ──────────────────────────────────┼─────────────────┼───────────────── Acute fermentative gastritis │ 18.│ 2.1 All other forms of gastritis │ 16.3│ 5. Acute toxic or fermentative │ 1.6│ 2.3 enteritis │ │ All other forms of acute enteritis│ 1.6│ 8.4 Chronic enteritis │ 0.│ 1.9 Colitis and typhlitis │ 0.│ 3.1 ──────────────────────────────────┴─────────────────┴─────────────────

Ungulates as a class stand in a position equivalent to the Primates in the incidence of gastrointestinal diseases. They show a conspicuous percentage of cases apparently due to incorrect food and, coupled with this, a high percentage of gastric involvement, being exceeded in this respect by the marsupials only (there is an adequate reason for this—see below). Cases ascribed to bacterial or parasitic agents are not numerous. Analysis of the records of the two groups discussed above brings out some interesting facts. Consultation of Table 12 shows percentage comparisons, based on the number of autopsies, of lesions in the various sections of the tract. Group A, that with the simple stomach and the short capacious colon, is represented by forty-four specimens, while Group B embraces 321 animals. Perhaps the use of these two widely differing figures for comparison is open to some objection which might be final and decisive were not the figures so definite. At a glance one can see that Group A has involvement more marked high in the tract while Group B has more disease in the intestine and colon. Certainly gastritis is more common (five times) in the A than in the B group, while enteritis is more common in B (over three times). No case of chronic enteritis or of involvement of the colon is recorded in animals with a simple stomach and a wide hind-gut. This may be read either in terms of vulnerability of the stomach or in the degree of resistance of the respective groups.

Consideration of the local factors of the stomach brings to light at once the fact that incorrect food entering the simple stomach could attack the softer, less resistant glandular section of the fundal and pyloric areas whereas the rumen and psalter of the compound organ, with their stratified epithelium devoid of glands, act as barriers or as places where detoxication of irritants might take place. In both groups bulky food is packed to the left, the esophageal and cardiac section in the simple form, the rumen in the compound. Soft or liquid food may pass into the psalter and abomasum of the ruminant stomach almost directly since it has not the force or bulk to push aside the valve-like fold of wall at the junction of esophagus, rumen and reticulum. For this reason, if for no other, the character of soft food supplied to this order must be unexceptionable.

It has not been possible to follow out the layering of diets as Scheunert did when showing the course of various foods before they are mixed at the beginning of the pyloric compartments. We have seen two cases in ruminants which seem to indicate that soft food had passed into the right side cavities of the stomach, there to cause irritation, while the rumen remained quite normal. It seems, however, accepted by veterinarians that excessive soft food may be followed by trouble in the digestive stomachs, while excessive dry food may cause distention of the left hand sections. So far as I know, the relative incidence of gastric disorders in the above outlined groups has not been pointed out before.

The pathological types of gastroenteritis do not present many unusual features. Simple injection of vessels during digestion seems more evident in this than any other order, while mucus production seems less marked. The mucosa of the reservoir portions may, in simple overfilling and fermentative distention (gastric tympanites), be quite normal or dull red; when active fermentation has occurred it may be digested and peel off. More or less true inflammation as seen in the digestive stomachs is definitely better expressed in the compound ruminant organ than in the simple equine variety where congestion and edematous swelling with hemorrhage form the usual picture. True catarrhal changes both gross and minute, are often well seen and ulcerative lesions are not uncommon; ulcers are unusual in the simple stomach. These statements hold good also for the small intestine. Enteritis affects the duodenum and jejunum more in the Perissodactyla and swine than in the ruminants. Ungulata do not react with hyperplasia of the mural lymphatics as do many other orders, but the swelling of the mesenteric nodes is often noteworthy. As might be expected this is more definite with catarrhal changes and therefore best seen in the ruminants. In the colon, however, the solitary follicles are often quite prominent in simple inflammation. Histologically the greatest changes seen in this order are superficial degenerations with mononuclear increase in the deep submucosa, mostly arranged in perivascular fashion. The villi do not contain the large number of cells seen in the Carnivora.

MARSUPIALIA.

Consultation of the figures for this order in Table 11 arrests attention at once because of the peculiar percentages found under the detailed factors. Thus food is of no moment as a disturber of the alimentary tract, while bacteria and parasites are high in importance. The gastric segment is more often attacked than any other portion and slightly more often than in the nearest order, Carnivora. These unusual figures deserve explanation, to which purpose it will be necessary to consider the anatomy of the organ and to discuss why bacteria and parasites stand so high in etiology.

Marsupials are divided into six families in our classification (see page 44) which in regard to their diet, range from largely carnivorous (the first two) through those choosing mixed insects, fruits and vegetables (the second two) to those eating vegetables and grain (the last two). The stomach of these animals does not vary exactly according to their diet, the first four, opossums, dasyures, bandicoots and wombats, possessing an organ closely similar in outline and construction and resembling the carnivorous variety, while the phalangers and kangaroos have a stomach entirely different from the first four although somewhat similar to one another. The first group has a round or irregularly elliptical organ with the esophagus and pylorus close together along the lesser curvature. The wombats have a bank of glands surrounded by a capsule, near the cardia. The stomach of the first four animals is divided into cardiac, fundal and pyloric parts by the construction of their mucosa, the first mentioned division being a high, rounded pouch, rumen-like, well to the left. The phalanger’s stomach is more elongated, the two openings well separated and a fissure is found in the right end of the lesser curvature which serves to separate the pyloric part from the rest. The Macropodidæ all have a stomach resembling the human colon in being elongated, with longitudinal bands gathering it into sacculations. There is a distinct esophageal section to the left with a blind sac suggesting an ungulate rumen, a long tubular fundal, and a sacculate pyloric division.

The small intestine of the order starts with the opossums as a stout muscular and mucous tube fitted for meat eating, but as one proceeds to study the families downward in the list this tube becomes more delicate and longer. In the first two families the cecum is rudimentary and the colon very short as in cats, but the length and capacity of these parts increase through the bandicoots and wombats until in the strict fruit, vegetable and grain eaters, phalangers and kangaroos, the cecum is long and capacious and the colon relatively long and roomy.

TABLE 13. _Showing the Incidence of Gastroenteric Disease in the Two Forms of Marsupial Intestinal Tracts._ ═══════════════════════╤═══════════════════════╤═══════════════════════ │ Group A │ Group B │Carnivorous Stomach and│Herbivorous Stomach and │ Intestines 103 │Intestines 73 Specimens │ Specimens Per cent. │ Per cent. ───────────────────────┼───────────────────────┼─────────────────────── Acute gastritis │ 9.6 │ 15. │ Bacteria Verminous │ Bacteria Verminous Chronic gastritis │ 0. 13.6 │ 5.4 0. Acute enteritis │ 2.9 │ 1.5 Colitis incl. typhlitis│ 1.9 │ 4.3 ───────────────────────┴───────────────────────┴───────────────────────

Table 13 contains an analysis of the forms of gastroenteritis as they were described in the two groups of tracts, that resembling the carnivorous, that similar to the herbivorous intestinal construction, and according to the factor believed to be responsible. In the first group gastritis of an acute nature occurred in 9.6 per cent. of the 103 specimens. They were chiefly catarrhal in character and seem for the most part secondary to verminous infestation; at least six of the ten cases were associated with parasites. The process microscopically is catarrhal and deeply infiltrative. Group B has a high incidence of gastritis and here the evidence of bacteria or toxins is quite plain. Several of the cases were in animals showing also Kangaroo disease of the jaw with pneumonia or septicemia; the gastric lesion of streptothricosis will be described under that heading. The character of gastritis without jaw disease is somewhat different from that with it. Pathologically the process is a congestive and superficially necrotizing affair, forming upon the tips of the folds, small gray erosions or flat shallow irregular ulcers, which upon histological study consist of loss of tissue of the mucosa and some deep congestion with round cell groups but no reaction deep in mucosa or submucosa. True catarrhal inflammation has occurred, but not like in the opossums.

Chronic gastritis in the simple stomachs is almost exclusively in opossums harboring _Physaloptera turgida_, a worm which fastens itself more or less firmly in the mucosa and probably, with the assistance of bacteria, causes sufficient irritation to produce a hypertrophic change in the deeper layers and a destruction of the glands where it holds and a distortion of those nearby. One is reminded that Fibiger found spiroptera to be responsible for adenocarcinoma in rats; no tumor formation has been found in these animals, although one opossum with such a stomach had an adenocarcinoma mammæ. Small hemorrhagic spots may occur in the deeper layers, possibly where the worms have bitten. The rugæ are irregular or interrupted by knobs and papillæ.

Group B, stomachs showing chronic change, were all kangaroos. The three cases resembled the infiltrating necrotizing lesions as discussed under ulcers (page 175). The process showed an infiltration of the subsurface tissues with a gray slough over the densest part. The mucosa as a whole was irregularly rugous and spotted with red gray areas.

Altogether one gets the impression that in the simpler stomach, reactive inflammation is most prominent, while in the colonoid stomach degeneration is greater than reaction.

Intestinal lesions in marsupials are not common and not peculiar except in that they carry out the pathological reaction as seen in the stomach. The carnivorous intestine shows frank catarrhal changes, the herbivorous presents congestions and superficial necroses. These two groups then follow the descriptions as already given for carnivores and ruminants.

The colon presented in the first group, simple catarrhal or follicular change. In the second division the lesions resembled those in the stomach; they were only once of the three instances associated with streptothricosis.

AVES.

The class Aves has been treated in the chart precisely as have the mammals, but it is not possible to make the accurate diagnoses or to separate groups of lesions according to anatomy as was done for the latter class. Upon the average there is more gastroenteritis among birds than mammals, but when looking for an explanation of this, it was unfortunately necessary to enter in the “undecided” column of Table 11 a very great number of cases. This column would be greater relatively were it not for the parasites in parrots and gallinaceous birds, the entries for which are high. Besides this fact and that the owl stands at the top, the pigeons at the bottom of the list numerically, no further general statements are allowable. There are several orders with high values among those of which insufficient autopsies are at hand to cast percentages.

The avian alimentary tract seems to have developed according to the character of food the different varieties of birds consume if one may judge by the construction of the bill, the gastric musculature and the intestinal wall. Zoological classification has only secondarily considered this point, it being made incidental to the habits and habitats of birds. For this reason the orders as outlined on pages 44–46, placed as they are in historical evolutionary position, represent with few exceptions groups which have differing diets and, by the same token, differing gastrointestinal tracts. Classifications based upon habits of life (Raptores, Cantores, Natores), prove likewise too broad or too heterogeneous, while systems making character of food the chief criterion though apparently correct in reasoning and helpful in certain orders, (Accipitres, Galli) are found to present copious exceptions; moreover we are imperfectly informed of the exact diet that many families require or resort to in absence of their preferred food. I shall therefore discuss the chief diseases and distributions according to our classification, preceding the discussion by a brief résumé of the anatomical peculiarities of the avian alimentary tube.

The first digestive burden falls upon the proventricle where the principal juices are secreted while the muscular stomach or gizzard assumes the duty of gastric mastication. The lateral muscular bellies of its heavy wall grind the food and mix well the gastric juices. Its mucosa probably supplies only lubricant. In birds whose food is hard, corn and the like, this grinder is supplied with a dry horny internal layer, while a thick, moist, soft, epithelial surface is sufficient for carnivorous birds. All kinds of gradations exist between these extremes. The mucosa of the proventricle is always soft, but quite deep to permit the placement of compound tubular glands.

The relation of size of these two parts is subject to many variations.[22] The proventricle is larger proportionately in meat eating, fish-eating and fruit eating birds, the gizzard having the greater size in granivora and insectivora. In certain birds the mucosa of the two is separated by a very soft thin zone, an important fact in Psittaci since at this place spiroptera seem to penetrate to the glandular layer of both organs.

The duodenum begins in practically all birds, from a spherical cavity at the pyloric end of the gizzard, to be accredited anatomically to both sections. It passes downward, forms a long loop enclosing the pancreas, its distal end lying under the liver and near the gall-bladder. Near its end it receives the major bile and pancreatic ducts; smaller ducts from the liver and pancreas may enter near the pylorus or elsewhere along the loop. The small intestine is usually simple in its coils, but in the birds that eat grain, grass and greens, may be long and complicated. So too the colon, usually a very short segment, may be increased in the just mentioned group while the ceca are only of any considerable length in herbivorous birds. The length of the ceca is, according to Owen, related to the availability of food and the need the bird may have for exhausting the nutritive value of it. In carnivorous birds as in similar mammals, the whole gut, but especially the hind-gut, is very short and the ceca small or absent. But so they are in picarian birds which are chiefly herbivorous, but may eat meat.

GASTRITIS.

The double-muscle stomach, that with the two lateral plates and tough epidermal internal coating, is seldom the seat of disease. An excess of greens in the diet sometimes seems to soften or macerate the lining, while an excess of pebbles may cause erosions. Upon severe irritation this internal layer assumes the appearance of tanned leather and may crack. The proventricle of such a gizzard seems rather resistant to disease, particularly one would say, to infective processes, for catarrhal or ulcerative inflammation is uncommon. The saccular stomach with uniform muscular walls continuous with those of the proventricle, such as is seen in raptatory birds and parrots, offers a somewhat different picture. The internal membranes of these organs are definitely softer, seeming to swell with great ease, and the glands themselves are smaller both at the fundus and outlet, a construction which may favor their closure by swelling from simple congestion and edema. Catarrhal and ulcerative processes are definitely more common in such organs than in the first type or true gizzard.

ENTERITIS.

Enteritis of all orders is most outspoken in the duodenal loop, but a determination of the lesion must be made with some care. All the signs of intestinal inflammation—congestion, swelling and opacity, excess mucus or mucopurulent covering—must be present to justify a gross diagnosis of enteritis and even when these exist one fails at times to confirm the finding by microscopical section. These changes may be simulated by digestive activity so that it is but reasonable to demand them all in a clear cut fashion before applying the term enteritis. However, it is well known that cases in both human and veterinary medicine giving a satisfactory clinical picture of this disease may fail to show to the naked eye and under magnification the changes expected.

In the human being, the carnivore and the ruminant, the ileum presents the most definite picture of enteritis. In the bird, the duodenum shows the prominent lesions, and with the exception of specific diseases like blackhead, is always involved when the smaller coil of small intestine is affected. This is true whether the enteritis be nonspecific or be associated with cholera of chickens, ducks or parrots.

The colon presents peculiar lesions in but few birds. Ulcerative and necrotizing processes have been encountered in three orders, Psittaci, Anseres and Herodiones, suggestively like the specific forms seen in the ceca. Microscopy and one unsuccessful culture failed to reveal a mould or protozoön. The condition appears as a gray white plaque in the cloacal wall or it may spread up to the colon and around the urethral orifices. At times it is superficial upon the mucosa and may be covered by a pseudomembrane.

The chief interest in the ceca centres about enterohepatitis either of heterakis and amœbic origin or that supposed to be due to coccidia or Bac. scoticus. This specific form has been encountered only in Galli (three of the four families). It has been so well described by Hadley, Smith, Morse and Cushman that it is unnecessary to discuss it since we have nothing to add to its pathogenesis or pathology. At a later time some attention will be given to our experience with Quail disease. What is more interesting from a comparative standpoint, besides having a bearing upon blackhead, is the discovery of heterakis in the ceca, and hemorrhage and fatty change in the liver without amœbæ or coccidia in either place (unfortunately no bacteriology was done), in a Sebastopol Goose (_Anser domesticus_), a bird which has ceca not unlike the gallinaceous varieties. This is a single observation and must be treated expectantly.

Microscopically the avian digestive tract in its various inflammatory states presents a few noteworthy features. The primary reaction, sometimes the only one, to irritation is injection of the vessels in the villi or deeper mucosa. To this, however, is nearly always added a granularity of the epithelium, without much evident mucus (goblet cell) formation. When the epithelial degeneration is marked there appears a round cell increase in the deep mucosa shortly followed by a similar infiltration into the villi. True catarrhal enteritis as described for the cats is not as common as some combination of the changes just detailed, but when it occurs is best developed in the carnivorous avian tract. The most striking cellular finding is the round cell of the infiltrate. It is of the middle lymphoid size with clear protoplasm, or, when late in the disease, may be small and so-called adult. Polynuclears, unless eosinophilic, and endothelioid cells are rare.

The foregoing are general remarks concerning the pathology of the avian tract, and we are now ready to discuss briefly the reactions of the orders. I shall, however, omit mention of those in the right half of Table 11.

Passerine birds are represented better than any other order because they are more numerous in nature and therefore exhibited more generously in collections. This order is not especially vulnerable as to its alimentary tract, but this tube is often affected by tiny stones, bits of rust from cages and by acute general nonspecific infections to which these birds are quite susceptible. Upon many occasions intense congestion with and without tiny hemorrhages in the duodenum are all that can be found in the little birds and the diagnosis of enteritis is put down. Only about one-tenth of these birds have shown more or less definite catarrhal changes. Many birds have heavy infestation with worms which may activate bacteria.

The Striges and the Accipitres will be discussed together because of the similarity of their tracts and their diets. The reaction of their gastric complex has already been mentioned and what was written there can be extended to the intestine. The type of lesion is catarrhal and seems to be “meat bred” although this cannot be proven. They never have given positive heart’s blood cultures so that the disease seemed not to be septicemic. Liver and spleen have harbored colon and paracolon bacilli. It will be noticed that they have the highest incidence of gastric disease.

Psittaci, birds with a tract similar to the last two but with a captive diet of seeds, fruit and vegetables although they may eat small animals and insects in the wild, present figures under bacteria and parasites which explain the involvement of the alimentary organs. We have had two acute outbreaks of what seemed to be fowl cholera, judging by the pathology and the isolation of _Bact. gallinarum_ and we have frequent deaths with the same gross anatomy from which bacterial isolation has not been tried or was unsuccessful. At all events the enteritis of parrots is often a definitely infectious affair. We have also isolated _Bact. psittacosis_ on two occasions. Separation of the birds and cleansing of the exhibition spaces seemed to stop the disease. The lesions are hemorrhagic and superficially necrotizing in this group whether or not they are septicemic. Some have also shown a follicular appearance both grossly and minutely, one of which cases was associated with _Bact. psittacosis_.

The effect of animal parasites is chiefly exerted, for this group, in the proventricle where the S_piroptera incerta_ occupies the lumen and penetrates the mucosa or burrows under the inner lining of the gizzard. Enteritis is not especially associated with this infestation, death resulting more from inanition than infection; some few cases have had enteritis, others pulmonary disease.

Columbæ are not susceptible to disease in the parts under consideration. This order seems to have some tissue resistance, for their lesions are quite frankly catarrhal, more so than in most grain-eating birds.

The figures set against the Galli are swollen by the number of cases of enterohepatitis of one sort or another. Extracting these from the total leaves the order among the lowest. Their lesions are congestive and hemorrhagic, although they may show catarrhal cases. They seem to be able to summon mucus more readily than many other birds.

Anserine birds, though not very high in figures, present three conditions worthy of note. In the first place, acute simple gastritis occurs often, sometimes associated with foul green food, sometimes without any apparent cause. From the number of times that foreign bodies are present it seems probable that they contribute in some way. Excessive stones and sand, bits of glass, collar buttons and the like are sometimes found. Then the form of acute enteritis has always a hemorrhagic tendency, at least in the submucosa, while the mucosa may be swollen, opaque and covered with mucus. Upon histological study these intestines show intense swelling by cellular infiltrate and disappearance of the tips of the villi. The third observation concerns what is apparently a subacute or chronic process although this is not supported by microscopy. Certain birds will have a cast of mucus and epithelial detritus rather closely adherent to the wall. Under the microscope there may be slight evidence of chronic inflammation or there may be little amiss. These birds have usually been large ones, and several have come from the separate goose pens, not from the open lake where many birds are kept.

The struthious birds deserve a word. They have had a great deal of enteritis and mostly of infectious nature. Two instances have arisen from bird diphtheria, one from cholera and six from what later seemed to have been anthrax but was not diagnosed at the time. The character of the lesions in the struthious intestine tends to be hypertrophic and superficially erosive if not ulcerative. The changes are found with greatest clearness in the lower duodenum and small coil.

CONSTIPATION.

Having discussed the inflammatory conditions of the gastrointestinal tract we now come to the more or less definitely mechanical abnormalities, whether or not they depend upon preëxisting inflammation, and the subject of constipation will claim first attention. In the human being this condition is the result of bad habits more than any other one thing or all things together, I think it will be admitted. In the lower animals perhaps no such thing as habit of defecation exists so that one can with more certainty hold incorrect food, chronic catarrhs or physical obstruction as responsible. Veterinarians look upon excess of dry food and irregularity of work and food periods as the principal causes of constipation. These factors do not hold in zoological collections. As a matter of fact constipation is of minor importance in this menagerie, but a certain few cases are worthy of note. It has been mentioned in the diagnoses in only a little over 1 per cent. of the total, and of these the records indicate its importance only ten times (.2 per cent.); a few notes of these cases are appended. The first place of incidence is taken by marsupials (six kangaroos and one opossum), the second by ungulates (largely ruminants) and the third by Primates. It will be noted that with exception of the opossum, herbivorous mammals occupy the first places of incidence, carnivores falling well behind the orders named. This condition is quite infrequent in birds and is usually associated with the presence of seeds or parasites or with impaction in the ceca.

Primates, almost exclusively feeders upon carbohydrate and soft protein food, have shown as causes of constipation two outstanding conditions. A low grade of colonic catarrh with excessive pouchings of this tube has had constipation associated with it three times. One of these cases had small coproliths in the diverticula, one other a fecal concrement in the cecum. Another group of these cases with evidence of delayed passage of feces shows chronic peritonitis with adhesions, one of which seems certainly due to filaria in the peritoneal sac.

The seat of constipation in monkeys is practically always the colon. The carnivores while occasionally showing hard fecal masses packed into the colon, more often exhibit a constipation in the ileum. One case presented a nearly empty colon with a long scybalum just above the cecal valve. There is no peculiar associated pathology in the notes at my command.

Ungulata, showing next to the highest incidence, has its stoppage chiefly in the colon, but the lowest stretch of the ileum may contain balls of feces. In nearly every case one finds some grade of colonic catarrh. In two instances, there being a proctitis, it seemed as if the animal voluntarily restrained from defecating because of pain. The caput coli is the seat of stoppage in the Rodentia.

Marsupials give such a high relative incidence that especial search of their records was made, without, however, very definite result. In three of the seven cases an acute general infection existed, in one an acute peritonitis which seemed to emanate from a small ulcer in the ileum, in one an injury to the anal region was found while in the remaining two the notes would suggest that the lower intestine was atonic, judging by its distention, translucency and pallor. In five the stoppage took place in the large bowel alone, in the others both divisions being affected.

It is often difficult to establish a diagnosis of constipation in birds because many varieties form a long rather dry mass in the lower small intestine, to be moistened in the cloaca for discharge. Still again the groups with capacious ceca are apt to have them filled normally with firm casts. Diagnoses of fecal inspissation and stoppage in the smaller tube have been made seldom, but one must consider also the obstruction offered by excessive urate collections either in the cloaca or lower ileum which will amount to a constipation if the cloaca be over-dilated and dried urates mixed with dirt or feathers cover the anal opening.

The causes of this condition in birds are usually mechanical, inflammation being found in a small minority of cases. In the small passerine birds, seeds, sand, or parasites form the commonest findings. This is also true of parrots, while excessive urate collections are noted for both these groups. The gallinaceous birds present two reasons for fecal stoppage—disease of the ceca (see pages 205–6) and cloacitis probably secondary to anal closure by excessive urate collection. Uratic stones, varying from one to five millimetres in diameter, have been found in the cloaca in several orders. In only one case, a pheasant, did they cause ulceration and cloacitis. Sand, rust, grains and the like are found frequently, and sometimes in groups of birds, indicating that the specimens had not been put upon the correct flooring or caging. Unbroken seeds may obstruct the lumen.

MECHANICAL OBSTRUCTION.

Although the following is not constipation it is well to cite at this place an experience which amounted to mechanical intestinal obstruction. A number of finches were subjected to postmortem and found to have whole white millet seeds in their intestines, this being the only discoverable cause of death. Investigation revealed that during the night mice ate the canary seed in the pans, leaving only the millet, which the hungry birds consumed whole. Small birds can take a few millet and crack them when eating leisurely, but apparently not when hungry. When the food was removed at night the trouble ceased.

Obstruction by sand is well illustrated by a peculiar form of pica, in a goose, which is worth citing, and calls to mind the sand disease of horses:

Canada Goose ♂ (_Branta canadensis canadensis_).

DIAGNOSIS.—Masses of sand in entire intestinal tract. The general condition externally and internally is good. The crop is distended like a sausage, quite firm and the overfilling is obviously due to sand in which very few stones, which could be called pebbles, are found. This mass continues into the esophagus making the whole tract impassable for food. The mucosa is a little pink and dirt-stained in places but is not visibly inflamed. The gizzard is contracted over a mass of sand but no food. Sand in more or less definitely packed condition is found all along the gut tract, in one place in the small coil it being quite as tight as in the crop and no lumen remaining. Sand and bits of shale are found in ceca. The organs are apparently healthy, slightly pale perhaps, but certainly not distinctly anemic. No infection exists. The aorta, just above renals, has a 15 mm. × 2 mm. pale opacity of same consistency as the rest of the vessel, just perceptibly higher than surrounding surface.

“Sand disease” has occurred in a Persian Wild Ass (_Equus onager_) causing in this case ulceration, perforation and peritonitis, a Common deer (_Mazama virginiana_) and a Chapman’s zebra (_Equus burchelli chapmani_). The collection of sand is always greatest in the caput coli, but may coat the large bowel to the anus.

Larger and more definitely obstructive physical objects are found in both mammals and birds. We have on record a lion (_Felis leo_) and a tiger (_Felis tigris_), which swallowed pieces of bone large enough to be stuck in the small intestine and completely occlude it. Smaller objects like buttons have been found even in the passerine tract. Worm masses may occupy such a large part of the lumen of the tube as to constitute a physical obstruction. This is definitely less important in mammals than in birds, especially in the passerine order of the latter class.

Dilatation of the intestine aside from that occurring in connection with fermentation, constipation or ileus, in other words chronic atonic dilatation, has not been encountered. Acute dilatation has been found in several orders under the picture known for domesticated animals. Its pathology and incidence have already been discussed.

ILEUS.

Ileus or acute intestinal obstruction may be divided for our purposes into intussusception, volvulus, strangulation and paralysis from interruption of mesenteric circulation. Examples of all these varieties have been encountered and illustrative cases will be cited. In so far as incidence is concerned, the Ungulata and Carnivora greatly outnumber all other orders, showing seven cases each; the sum total in all other orders is but eight. Upon re-reading some of the protocols I have, however, excluded three invaginations in the carnivores, one each in the ungulates and rodents, as probably being postmortem or shortly antemortem occurrences; two had very early peritonitis but other things, sufficient to account for death, were present. These deductions bring the total cases of ileus in mammals to seventeen. Five cases in birds will be discussed briefly.

Primates present one case of volvulus, one of intussusception and one of internal strangulation. The first displayed the entrance of four inches of ileum into the colon with such swelling of the wall as to prevent reduction. The exciting cause seemed to be an enteritis, the cause of death a peritonitis. A white-collared mangabey (_Cercocebus collaris_) was the victim of volvulus probably favored by an anomalous position of the transverse and descending colon which lay to the right, the latter traversing the abdomen obliquely from right to left to reach the pelvis. The volvulus occurred in the ileum just above the cecum, the twisted part being found adherent by the peritonitis. The third case is a strangulation due to peritonitis from filaria and adhesions between stomach and colon from a colitis and pericolitis due to cestodes, one of which was found deeply implanted in the colonic wall.

Two cases of intussusception are noted (after deductions above) for the Carnivora. They both occurred in the ileum, one restricted thereto, the other extending into the colon. In both a vague history of being “off their feed” or giving evidence of intestinal trouble could be obtained from the keeper. The three excluded cases had invaginations in the middle and lower small intestines but not at the cecal valve. Volvulus did not occur in the Carnivora.

A paradoxure (_Paradoxurus hermophroditus_) died as the result of a strangulation of a six-inch knuckle of gut which had passed through a hole in the omentum. The animal had not been eating well for a month but gave no signs by which this ileus could have been diagnosed. Perhaps it had existed for sometime but only shortly before death had swollen sufficiently to cause obstruction.

Having excluded a doubtful invagination in a small rodent there remains an interesting though somewhat obscure case in a porcupine (_Erethizon dorsatus dorsatus_). This animal suffered with an acute hemorrhagic and catarrhal enteritis while the colon seemed free of change until the rectum was reached. Here was a stretch of a foot with the purple, lusterless but translucent appearance of a strangulated intestine although no involution or twisting remained. This was looked upon as a volvulus which had untwisted a few hours before death.

Intussusception was seen only once in the Ungulata, a tapir (_Tapirus terrestris_) with chronic enteritis. Here the ileum had passed into the colon for a distance of nine inches, it being much swollen and congested but not gangrenous. Its condition warranted the idea that the process was antemortem but a peritonitis had not arisen, death having occurred from the slight extra shock in an animal suffering with chronic malnutrition. Volvulus was encountered three times, two deer and a zebra. The last was the animal already described that carried such a heavy load of sand in the gut tract, a factor in the production of the twist probably although this might have been aided by a fibromyoma of the colonic wall. The location of the volvulus in this order was twice in the dilated descending colon, the third in the jejunal area. This last was a twist which resembled an internal strangulation because of the intricate knot-like windings of the small bowel.

The marsupials present two interesting cases. A rock kangaroo (_Petrogale pencillata_) had chronic gastric ulcerations with local peritoneal adhesions which apparently obstructed nearby coils of intestine so that they became inflated and twisted over. An opossum had a volvulus of the stomach which performed one and a half turns from left to right; its protocol follows.

Common Opossum ♂ (_Didelphys virginiana_). Ileus. One and one-half complete volvulus turns of stomach on duodenum. General condition fairly good. Abdomen quite prominent, a condition found to be due to great dilatation of the stomach which occupied the whole anterior part of the abdominal cavity. The organ is blue and the vessels stand out. Postmortem changes are occurring everywhere favored by the obstruction to the circulation. The dilated stomach has undergone a volvulus upon the third part of the duodenum making one and a half turns. The spleen lies upon the right side well below the liver; it is swollen, soft and deep purple. The duodenum in its upper half takes part in the dilatation and beginning gangrene. The pedicle of the twist is made of the duodenum, esophagus, edge of the mesentery and the middle part of the pancreas; the end of the tail of the last is gangrenous. There is no apparent obstruction lower down to explain the twist of the stomach.

Among the Aves the following cases only are worthy of report. A parrot (_Melopsittacus undulatus_) was found to have a tightly packed mass of worms in the end of the duodenum above which the bowel was distended, elongated, doubled on itself and of a deep red color; below this the small intestine was empty. A closely similar condition was found in a Screech Owl (_Otus asio asio_) the obstruction occurring just above the end of the small gut. A Sparrow Hawk (_Falco sparverius_) had an invagination two cm. in length, a short distance above the end of the small intestine. No peritonitis existed but the presence of an acute enteritis helps to explain the intussusception.

HERNIA.

Hernia is not a common occurrence among the lower animals but our experience is instructive in two particulars, to wit, its absence in the orders preceding the Rodentia and the frequency of the traumatic variety. There being no general remarks to be made upon the subject, it seems well to give a summary of the findings in each of the seven cases.

A Western Fox Squirrel (_Sciurus rufiventer_) showed a diaphragmatic defect on the right side, a rounded opening with smooth edges, through which a loop of intestine had passed, entering behind the liver and reaching into the pleura as high as the pulmonary apex where it was adherent; this was probably of long standing. Two more loops were found wedged in the diaphragmatic hole, one of which was gangrenous.

An Indian Antelope (_Black Buck_) (_Antilope cervicapra_) presented an irreducible incarcerated but not strangulated umbilical hernia. The peritoneum was fused with the aponeurosis at the ring but the gut was not adherent at this point while it was attached within the sac outside the muscle, thus forming the incarceration. Apparently the sac had dissected between the muscular layers for it could be followed for several centimetres in some directions. A Hog Deer (_Cervus porcinus_) had apparently suffered an injury in the flank for at one point the muscles were irregularly cicatrized and a rent was present through which several loops of intestine and a band of omentum had escaped, being adherent to fascia. No injury to the skin was apparent.

Another Indian Antelope showed a clean traumatic rupture of the muscle _and peritoneum_ in the right inguinal region _without_ penetration of skin. An acute hernia had occurred which was lightly adherent to fascia and an acute peritonitis was beginning. The bowel was however not strangulated.

An aoudad (_Ovis tragelaphus_) seems to have suffered an injury by a pointed object (horn?) just to the right of the ensiform cartilage for at this position there is a circular hole, with smooth healed edges, in the aponeurosis, permitting the emersion of a peritoneal sac containing omentum. All parts were adherent but no acute inflammation existed.

What may have been a hernia or a relaxation of the transversus perinei was observed in an Undulated Grass Parrakeet (_Melopsittacus undulatus_). A bulge about the size of the finger end was seen externally, beside and behind the anus. This proved to contain several loops of bowel and a mass of fat.

A lateral abdominal hernia was seen in a Barbary Turtle Dove (_Turtur risorius_). It consisted of a peritoneal sac and two loops of intestine. This protrusion, while firmly fixed in its unnatural position, was in no way constricted.

RECTAL PROLAPSE.

Prolapse of the rectum may in a sense be looked upon as a hernia or at least as a relaxation of the anal and perineal muscles with protrusion of parts normally situated intracorporeally. Although not frequent it has been incurable in the animal, as it frequently is in man without operation, a measure we have not adopted. Just what determines weakness in the pelvic outlet is entirely obscure for indeed we have seen here wounds and inflammations of the perineal area without prolapse of the rectum and in none of the cases of prolapse did the pelvic floor seem injured or diseased. It is but speculation to blame the annular muscles of the anus. Tenesmus, or at least reasons for this straining action, have been sought, with the result that in our cases lesions of the egg- laying apparatus in birds and enteritis in mammals have stood out most prominently. In no case have hemorrhoids been encountered nor has a tumor pendant from the colonic mucosa, drawn the bowel toward the anal opening. It might be added parenthetically here that hemorrhoids are practically unknown for quadrupeds, Hutyra and Marek failing to mention them independently and only one reference being found in the _Jahresbericht fur Veterinär Medizin_ (Schmidt 1914–169); this case is more like angioma than hemorrhoids. If tenesmus be active in the production of rectal prolapse then it would have to be assumed that this straining effort can be induced by enteritis since eversion of the rectum has occurred with this disease in the absence of colitis, the condition usually expected in the presence of tenesmus. The thirteen cases have been seen in Mammalia, 8, (Carnivora, 2, Rodentia, 1, Ungulata, 3, Edentata, 1, Marsupialia, 1) and Aves, 5, (Passeres, Picariæ, Striges, Psittaci and Galli each one). Three mammals had enteritis, one had foreign bodies in the bowel and one had many ascarids; three had no demonstrable or suggestive causes. Two of the five birds had enteritis high in the tract, one had uratic calculi in the cloaca, and three had trouble in the egg-laying apparatus: one too large an egg, one a broken egg and one a salpingitis.

DIVERTICULA.

It is almost certain that in a human pathological service of fifty-five hundred autopsies, one or more diverticula of the Meckel variety would be encountered and perhaps several of other kinds. In our material only pouchings or false diverticula of the colonic wall are recorded, and our personnel has often spoken of the absence of these gross abnormalities of the alimentary tract. The two cases, notes of which are given, are instances of hernial pouchings of the colonic mucosa and serosa, a condition which is well known in human medicine. It may be said to occur in two varieties, one in which the pouchings have heavy walls formed by a thickened mucosa, muscularis and peritoneum and one in which the bulgings have delicate walls, then being small herniæ of the inner coats through rifts in the outer. Such a division is probably unnecessary or misleading since the latter may be only a forerunner of the former. However the clinical evidence of the simple variety is scanty and may be little more than constipation while the peritonitic variety gives a clinical picture of pain, constipation and a mass in the left abdominal area, then known as diverticulitis or pericolitis sinistra. In these cases the colon is much distorted by the irregularity of its mucosa and by inflammatory thickening of the muscularis and serosa. Diverticula arise from defects of the muscular coat, or secondarily after inflammation or prolonged constipation, by weakness of muscle, or as hernial protrusions around the entrance of blood vessels where the muscle is thin. Such sacculations permit feces to collect and continue the inflammation, thus further weakening the gut and producing constipation, the whole vicious cycle being favorable to the formation of more sacculations; coproliths may form in the diverticula. The two monkeys now reported seem to have varying grades of the same condition, a long standing colitis with diverticula, constipation and the collection of inspissated feces in the sacculations. These animals did not have hemorrhoids.

Black Ape ♀ (_Cynopithecus niger_). Coprostasis. Coproliths in diverticulum. Chronic colitis. Cor bifida. The large intestine is of the same calibre as the small intestine should be when not distended. The sacculations as seen before opening the organ are salient, forming distinct pouches. In one or two cases they are so pronounced as to constitute diverticula 7 cm. long. In two instances the serosa at the fundi of these diverticula is markedly hyperemic and very thin. In many cases the sacculations contain coproliths. The wall of the organ is distinctly thickened, puckered, inelastic and opaque. Mucosa is thrown up into coarse rugæ.

Japanese Macaque ♂ (_Macacus fuscatus_). Chronic hypertrophic colitis. False diverticula of colon. The large intestine contains a moderate quantity of quite constipated feces. The serosa is smooth. The wall shows at several stretches enlargements of the normal sacculations, forming false diverticula. The wall of the gut in these herniæ is thinner than in the surrounding parts; no ulcers exist; no local peritonitis is present. The mucosa everywhere is irregular in thickness, less translucent than normal and thrown into irregular rugæ; tenacious mucus covers it. No ulcers.

TUMORS.

Only one tumor was observed in the mammalian intestinal tract proper. Dasyure (_Dasyurus maculatus_) Adenocarcinoma of the intestines. On postmortem there was a pale diffuse thickening of the coats of the small gut over a large area; numerous soft, light yellow, sharply circumscribed, elevated (like secondary tumors) nodules in the liver and spleen, and a pea-size whitish nodule around a bronchus in the right lung. Histological section of primary growth not made but a cross section of the intestine in the vicinity shows an adenomatous change with considerable increase in the connective tissue. The nodules in the liver, spleen and lung and the appearances of the abdominal lymph nodes, found microscopically, are precisely similar. They consist of irregularly arranged epithelial nests and distorted acini, around which are sharply outlined spaces, filled with the remains of degenerated blood or a granular material. The metastases are always sharply outlined.

Aves supply three papillomata which are interesting in that one occurred in the proventricle, and two grew in the duodenum in the vicinity of the upper biliary opening and presented within the lumen soft masses which, while not occluding the passage, offered some little obstruction as indicated by a slight distention above their location. In two, carefully studied, no indications of parasites or of cancer could be found. The birds concerned were an amazon, an owl, and a rhea.

SECTION VII THE ALIMENTARY TRACT,