Part 21

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.