Scientific Proceedings. (209) 39 



lumen, though perhaps here and there partially obstructed by 

 leucocytes, is always sufficiently open to permit the free passage 

 of bile. Bile is never found in the urine. In no case have the 

 authors ever found anything suggesting cirrhosis or degeneration 

 of the liver cells. 



18 (no). " Tumors of wild animals under natural condi- 

 tions " : HARLOW BROOKS. 



The author referred to the great importance of the etiology of 

 neoplasms and the well-recognized fact that research along this 

 line must now rest almost entirely on experimental studies of the 

 lower animals. By this series of observations the author hoped to 

 establish what may be called a " normal " rate of occurrence. 

 This can be based only on observations of large numbers of ani- 

 mals which have been in captivity for only relatively short periods 

 and which must be kept under far different conditions than is pos- 

 sible in the ordinary zoological park or in the laboratory animal 

 house. 



The author's observations were made on a large number of 

 wild animals, most of which were captured direct from the wild, 

 and which after capture and transportation were placed under the 

 most carefully studied natural conditions ever attempted in any 

 large zoological collection. 



The occurrence rate of new growths in such a group of ani- 

 mals, comprising most of the known species of the reptiles,U)irds, 

 and mammals should furnish a valuable contribution to the study of 

 the etiology of tumors, especially since the animals included in this 

 collection were, for the most part, at least, pure and uncontami- 

 nated, except for such crossing as normally takes place in nature. 

 The animals of the New York Zoological Society have been 

 selected by experts for their purity of type and every one is sub- 

 mitted to a careful veterinary examination before becoming a mem- 

 ber of the collection. Notwithstanding that this examination 

 might have been expected in some cases to have excluded animals 

 afflicted with tumors, the records show that none have been 

 rejected for this defect. 



Of 2,645 living animals which have been under the charge of 

 the author and his associates for the past five years, no case of 



