76 



Scientific Proceedings (32). 



taneous deterioration that was seen to take place in solutions stand- 

 ing at corresponding temperatures, and also at body temperature. 



One per cent, solutions of a commercial pepsin in hydrochloric 

 acid (o. I per cent., 0.25 per cent, and 0.5 per cent.) were kept in 

 glass bottles at approximately the following temperatures : 5° C, 

 20° C, 33° C, 37° C. From time to time samples were tested 

 by Fuld's method, modified somewhat to decrease the error. The 

 following results were obtained for solutions in 0.25 per cent, hy- 

 drochloric acid at 37° C. : 



Duration of heating 

 in days. 



o. 5 days. 

 0.84 

 i.o 

 1.2 

 2.0 

 5-0 

 8.0 

 12.0 



Destruction. 



19. 5 per cent. 



31 



35 



39-5 " 



S3 



73 



80 



86 " 



t{i-x) 



.48 



•53 



These results seem to indicate that the destruction of pepsin 

 under the conditions described takes place in accordance with the 

 law of the bimolecular reaction, and the formula which seems to 

 apply is : 



X 



t{i-X) 



where X represents the destruction, in hundredths of the original 

 in time /, and K represents a constant. 



35 (373) 

 Synthesis of uric acid. 



3y NELLIS B. FOSTER and JAMES 0. GREENWAY. 



^From the Laboratory of Biological Chemistry of Columbia Univer- 

 sity, at the College of Physicians and Stirgeons, and the 

 Wards of the New York Hospital.'] 

 The possibility of a synthesis of uric acid from lactic acid and 

 Tarea has been considered by a number of investigators, but when 

 these substances are taken by way of the stomach, all researches 

 alike have failed to disclose any evidence of uric acid synthesis in 



