and infiltrated mucous membrane, which is unable to produce the digestive ferments or to permit of normal absorption.

In all cases where the disease has been of long standing, and sometimes in acute cases as well, the kidneys become diseased, and present typical pictures of acute exudative nephritis or, more rarely, of hæmorrhagic nephritis.

In regard to the causes of this gastro-enteritis, judging from analogous lesions occurring in the human subject (where the conditions have been most carefully studied), I have no hesitancy in pronouncing them qualitative and quantitative errors in diet. Indeed, I think we may with entire justice compare this condition occurring among our animals with the similar disease so prevalent in infant asylums and hospitals, where, in artificially fed children according to the official statistics of the German government, 51 per cent. die of a similar gastro-intestinal disorder (Winter). With our limited space and flora we can hardly hope to approach more closely the natural self-selected food for our ruminants than cows' milk, or artificial preparations, approach the maternal milk for the human. As a rule, I believe that the causative agent in the production of this gastro-intestinal irritation is abnormal fermentation of the food, and I have usually found that this process is most marked when the animals have fed at will on fresh food such as the grass growing in their inclosures.

I believe that better results could be attained by limiting the quantity and increasing the variety of the food, attempting to reproduce, in so far as possible, the conditions and flora under which the animals normally live. The difficulties of following out this very simple and entirely obvious suggestion can hardly be appreciated by those who have not tried it, and who fail to realize the limitations of space and possibility in these respects imposed by a park situated on the valuable land of a great city. I feel very hopeful, however, that continuation of the methods already adopted at the Park, especially that of securing young animals, in which we may reasonably look for better results in the way of natural adaptation, will finally solve this serious problem in a reasonably satisfactory way.

There is still another source of gastro-enteritis which we have to consider, and one which, owing to the firm stand already taken by the director, I believe should be practically eradicated by next year. That is the gastro-enteritis produced by the presence of foreign bodies in the stomach. These have been given the animals by mischievous or thoughtless visitors. Three valuable specimens have died from this cause alone during the past year. One, an expensive Japanese bear, had been fed peach-stones in such quantity as to effectively block the pylorus, producing an extreme acute, gastritis, with finally complete pyloric stenosis. Similarly, one of the deer had been given leaflead in such an amount as to set up a fatal gastro-enteritis. Director Hornaday has taken stringent measures to stop this abuse, and he should receive the assistance in this work not only of the members of the Zoological Society, but also the help and co-operation of every animal lover. The idea is all too prevalent among the public that animals can "eat anything."

DYSENTERY AMONG THE PRIMATES.

Dr. Miller has dealt quite extensively in his report with the epidemic of dysentery which occurred among the orangs, and which also affected the chimpanzee, with the result that all but one of these animals died.

Pathologically, this epidemic has been of great scientific and practical interest, inasmuch as we have been able to identify the cause of the disease, and this knowledge has enabled us, thus far at least, to save one member of the orang family.

The etiological factor of this epidemic was the Balantidium coli (Paramecium coli), a parasite belonging to the order Heterotricha.

This organism was discovered by Malmsden in 1857, in the mucous discharges of a patient who suffered from a persistent diarrhœa following cholera. It is an oval body about four to seven times the diameter of the human red blood-cell. It is completely covered by cilia, arranged in parallel rows. An ectosarc and endosarc are usually clearly shown. The mouth is funnel-shaped, much like that of the ordinary paramecium, and is surrounded by a row of cilia which are larger than those over the organism. There is also a small anal orifice at the posterior extremity of the oval. The paranucleus is bean-shaped, and reacts diffusely to chromatic stains. The cytoplasm is granular, and contains two large vacuoles; it often incloses bacteria, red blood-cells, small granules of dirt, fat, or other material taken up from the medium surrounding the parasite.

The Balantidium is quite actively motile, but soon loses its motility if exposed to cold, acids, or disinfectants. Solutions of quinine, creolin, or other similar agents, apparently soon kill it unless it be encysted or protected by the tissues.

These paramœcia are found normally in the fæces of swine (Leuckhart, Stiles). In man it is present only when associated with diarrhœa or other intestinal disease (Doplein).

The pathogenicity of this infusorium is still in question. Beyond doubt it may be considered as a normal inhabitant of the intestine of the hog, as stated by Leuckhart and Salmon, but in other animals its innocence is not as clear. As mentioned above, it has been found in the human subject only when associated with diseases of the intestine, particularly after cholera or typhoid, and associated with the Amaba coli in tropical dysentery. I am informed that Strong, of the army, now Director of the Pathological Laboratory at Manila, states that it is undoubtedly a pathogenetic factor in the production of the dysenteries prevalent in the Philippines. The observations of this scientist should receive the most respectful attention on account of the great facilities afforded him for the study of diseases of this class and because of his previous accurate and careful work. Experiments conducted by us seem to demonstrate that feeding by the stomach, in the lower simians, or injecting into the colon of fæces rich in living Balantidium coli, will not produce the disease in certain members of the monkey family. Unfortunately for the Zoological Park, however, our experience has demonstrated beyond doubt that the parasite is pathogenic to the orang and the chimpanzee.

It should be noted, as pointed out by Dr. Miller, that all the animals fell sick at the same time. Throughout the entire epidemic, after routine microscopic examinations of the stools had been instituted, it was clearly shown that the degree of diarrhea present and the severity of the general symptoms corresponded with the number and activity of the parasites found in the fæces. Disinfectant enema caused a retardation or cessation of movement in the organism, and was followed by amelioration of the symptoms.

Concerning the lesions produced by the Balantidium coli in the higher primates, I can perhaps best illustrate from the somewhat voluminous protocols of the examinations conducted upon the orangs and chimpanzee, which died from the disease.

In these animals all the viscera except the colon were free from gross lesions, but in each instance the body showed many indications of the profound exhaustion which terminated the disease. Microscopic examination of the heart showed an acute fatty degeneration of the myocardium; the liver and kidneys exhibited the same pronounced change.

The mucosa of the stomach and small intestine, though partaking somewhat of the general anæmic condition, were practically normal, and the small amount of food found in these tubes was apparently in a natural condition of digestion. In the lower part of the ilium fairly well-formed fecal masses were found; but, beginning with the caput coli, the conditions were entirely changed, and the fæces were very fluid, flecked with blood, mucus, and pus, and of a very foul odor.

In the most severe case, that of "Rajah," the entire mucosa of the colon was transformed into an almost continuous succession of large irregular ulcers. The ulcers showed raised, ædematous, undermined borders. The bases of the ulcers were made up of a dark sloughing tissue, and a good many extended down to the peritoneum; and, though none had macroscopically perforated, the peritoneal surface of that portion of the gut was covered with a recent septic exudate.

Microscopic examination of sections of these ulcers showed myriads of the parasites burrowing beneath the mucous membrane, even along the lymphatic channels of the muscle coat and, in places, as far down as the peritoneum. In some areas the parasite was so abundant as to almost completely fill the field, obscuring or displacing the tissues.

Sections of mucosa, intervening between the ulcerations, showed frequent Balantidia on the free surface, and small colonies of from two to six or eight in the dilated bases of the crypts of Lieberkühn.

The protoplasm of many of the parasites contained frequent blood and epithelial cells, as well as detritus and numerous bacteria. Needless to say, the floors and sides of all the ulcers showed bacterial infiltration, and the adenoid tissue was everywhere much inflamed.

In the case of "Brunei," healing had begun in many of the ulcers, and these were not as frequent as in the other animals. The parasites were less numerous, and apparently the animal

BALANTIDIUM COLI IN AN ORANG-UTAN.

A micro-photograph, magnification, 94.5 diameters: section through ulcer of colon, showing the undermined character of the ulcerations, and the presence of numerous Balantidia coli in the submucosa. A, intestinal gland; B, inflamed follicle; CC' C", Balantidia coli.

had died from exhaustion and malnutrition consequent upon the ulcerative colitis.

In the colon of "Sultan," who recovered from the first epidemic but died from a subsequent attack, only a few recent ulcerations were found, but the mucosa of the colon was almost obliterated from the contraction of the scars resulting from the former attack. In the recent ulcerations, and in the dilated crypts, the Balantidium coli was found, as in the other cases.

The colon of the chimpanzee showed a marked general atrophy of the mucosa resulting from healing of previous ulcer

C