Blood Coagulation. 



79 



With thymol blue standards the determination of the P H of 

 gastric juice may be very easily and quickly made. 

 Other uses of this instrument are being considered. 



42 (1789) 



The effect of pancreatic rennet on blood coagulation. 



By ALBERT A. EPSTEIN and NATHAN ROSENTHAL. 



[From the Department of Physiological Chemistry, 

 Mt. Sinai Hospital, N. Y. City.] 



At the last meeting of this society, one of us 1 presented certain 

 observations on pancreatic rennet. Particular stress was laid on 

 the state in which the rennet probably exists in pancreatic extract, 

 and its intimate chemical association with trypsin. In speaking 

 therefore of the pancreatic rennet we wish it understood that it is 

 the rennet-trypsin unit and not the rennet alone that we are 

 dealing with. Mention was also made of the absolute dependence 

 of the milk coagulating function of rennet on the calcium ion. 



The theoretical considerations which have prompted the pres- 

 ent investigation will be discussed fully at another time and place. 

 Suffice it to say for the moment that rennet (as a class) appears to 

 be widely distributed in nature, in the animal as well as in the 

 vegetable kingdom. In the latter, its native function often seems 

 to be that of a coagulant of the sap of the plant in which it exists, 

 a process comparable, in some respects, to that of blood coagulation. 



Our first attempt to discover the effect of pancreatic rennet 

 upon the coagulation of the blood consisted in the following simple 

 experiment. A small quantity of the purified pancreatic rennet 

 was added to a portion of blood freshly drawn from the cubital vein 

 of an hemophilic individual, and the coagulation time noted. We 

 found that whereas the blood in the control tube required 1 hour 

 and 20 minutes for coagulation, the specimen to which the rennet 

 was added clotted in 90 seconds. The result was so striking that 

 we determined to make a careful investigation of the phenomenon. 



In a study of the effect of various tissue extracts on blood 

 coagulation, Mills 2 found that a saline extract of pancreas has very 



1 Epstein, A. A. f Proc. Soc. Exper. Biol, and Med., 1921, xix, 3. 

 * Mills. C. A., /. Biol. Chem., 1919, xl, 425. 



