Studies on the Life Cycle of Paramecium. 117 



61 (399) 



Observations on uricolysis, with particular reference to the 

 " uric acid infarcts " of the newborn. 

 By H. GIDEON WELLS and HARRY J. CORPER. 



\_Fro;n the Pathological Laboratory of the University of Chicago.'] 

 Mendel and Mitchell demonstrated that in the embryo pig the 

 enzymes concerned with purin metabolism appear at different 

 stages of development, the uricolytic power not appearing until 

 after birth and being feeble during the first months of extra-uterine 

 life. If the same late development of uricolytic power were present 

 in the human fetus it would explain the occurrence of deposits of 

 urates in the kidneys of newborn infants. Schittenhelm and Schmidt 

 alone have studied uricolysis by infantile and fetal tissues, and 

 have claimed to get active uricolysis. This result is questionable, 

 because later work by Kunzel and Schittenhelm indicate absence 

 of uricolysis by adult tissues. We have found no evidence what- 

 ever of uricolytic activity on the part of fetal tissues at any stage 

 of development, nor of adult tissues. The latter observation is in 

 harmony with the negative results obtained by Wiechowski in ex- 

 periments in vitro and in vivo, and indicates that the human body 

 has little if any power to destroy uric acid. The statements in the 

 older literature that allantoin is found in the urine of pregnant 

 women has been disputed by Wiechowski, and our failure to 

 demonstrate uricolysis by human placenta as well as other fetal or 

 adult human tissues points in the same direction. 



Additional observations are the demonstration of active urico- 

 lysis by the liver of the guinea pig, absence of uricolysis by spleen, 

 bone marrow and probably the leucocytes of the dog, and the 

 apparent absence of inhibitory power of dog serum upon uricolysis 

 by dog liver. 



62 (400) 



Studies on the life cycle of Paramecium. 

 By LORANDE LOSS WOODRUFF. 



\_Froin the Sheffield Biological Laboratory of Yale University.'] 

 A year ago I reported to this society the results obtained up 

 to that time on the life cycle of Paramecium when subjected to a 



