110 NEW YORK ZOOLOGICAL SOCIETY. 



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 hsemorrhagic 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 condi- 

 tion 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 dis- 

 order (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, ap- 

 proach the maternal milk for the human. As a rule, I believe 

 that the causative agent in the production of this gastro-in- 

 testinal 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 prob- 

 lem 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 



