Blood Coagulation. 



81 



ened the coagulation time of this blood to 15 and 30 seconds 

 respectively. (Expt. 1, Table I.) 



We then tested once more the effect of the pancreatic rennet on 

 the blood of a hemophiliac and the results show (Expt. 2, Table II) 

 that the coagulation time could be reduced from 1 hour and 15 

 minutes to 2 minutes, by very small, but adequate amounts of 

 the rennet. 



TABLE 11. 

 Experiment 2. 



Effect of Pancreatic Rennet on the Coagulation Time of Hemophiliac Blood. 

 The control tests showed the clotting time of hemophiliac blood to be 1 hour 

 and 15 minutes at the beginning of the experiment and 1 hour and 20 minutes at 

 the end. 



Hemophiliac blood 1.0 c.c. 1.0 c.c. 1.0 c.c. 1.0 c.c. 



Activated pan. extract — I per 



cent 0.3 c.c. 0.2 c.c. 0.15 c.c. 0.1 c.c. 



(Rennet content) 0.003 c.c. 0.002 c.c. 0.0015 c.c. 0.001 c.c 



Clotting time 2 min. 4 min. 20 min. 29 mnu 



We next tested the effect of pancreatic rennet on citrated 

 normal plasma. In this experiment, as in that with whole blood, 

 we find that the rennet accelerates coagulation. The clotting 

 time is reduced from approximately 8 minutes to 30 seconds. Two 

 other facts come to light in this experiment, first, that the short- 

 ening of the coagulation time is proportionate to the concentration 

 of the rennet, and secondly, that the rennet is capable of coagulat- 

 ing citrated plasma without the addition of calcium chloride (see 

 Table III, Exp. 3, Column 3). The exact manner in which the 

 rennet accomplishes this result cannot be stated with certainty. 

 In the normal coagulation of blood, calcium is indispensable. It 

 will be recalled that rennet requires calcium for the coagulation of 

 milk. Hence, it must be assumed that rennet causes the clotting 

 of citrated plasma, either in a manner peculiar to itself, or that it 

 accomplishes it by causing a dissociation of the calcium ion from 

 the citrate molecule. The experiment indicates, however, that 

 the addition of extra calcium, in the form of chloride, enhances 

 the coagulating effect of the pancreatic rennet on citrated plasma. 



The intravenous injection of large doses of activated crude 

 pancreatic extract, or the purified rennet in rabbits is not accom- 

 panied by anaphylaxis or other symptoms. Intravascular clotting 



