Abstract
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 present 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 I 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 slight coagulating power for blood.
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