130 



Scientific Proceedings (38). 



agent. They, therefore, look upon the activation of trypsinogen in 

 pure pancreatic juice by enterkinose as absolutely specific. Lar- 

 guier des Baucels, Delezenne, and Wohlgemuth have been able to 

 activate the trypsinogen of pancreatic juice with a limited number 

 of substances other than enterokinase. From this short historical 

 sketch, one sees that though trypsinogen of fresh pancreatic 

 extract can readily be activated by a large number of substances, 

 trypsinogen of pure juice is activated with but few agents other 

 than enterokinase. 



It is well known that pancreatic juice when secreted is strongly 

 alkaline. In the course of the experiments here detailed, it has 

 been found that when fresh pancreas is brought in contact with 

 alkali, the activation of trypsinogen cannot be obtained by the use 

 of agents which are capable of activating fresh pancreas. In short, 

 the alkali-treated pancreas resembles pancreatic juice in regard to 

 its behavior toward activators. 



Fresh normal pancreas of the dog was allowed to stand on ice 

 in one flask in a concentration of 0.2 per cent, acetic acid; in an- 

 other, at neutral reaction, and in a third, in a solution of 0.2 per 

 cent, sodium hydrate. After twenty-four hours, the acid and 

 alkali were carefully neutralized and the proteolytic activity of the 

 mixtures tested in acid, neutral and alkaline medium. Degrees of 

 digestion are expressed in terms N/10 H 2 S0 4 . Bacterial growth 

 was prevented by the addition of toluol. The same quantity of 

 pancreas was used in all experiments. The duration of digestion 

 was, in every instance, twenty-four hours at 37 0 C. Beef serum 

 denaturalized by heat served as substrate. 



Treated with Treated with 



0.2 per cent. 0.2 per cent. 



Medium. acetic acid. Untreated. 6odium hydrate. 



0.2 per cent, acetic acid 11.0 c.c. 12.4 c.c. 0.2 c.c. 



Neutral 16.4 " 4.8 " 0.9 " 



0.2 per cent. sod. carb. II. 2 " 0.6 " 0.3 " 



In this experiment, treatment with 0.2 per cent, acetic acid has 

 developed proteolytic activity in all media. In untreated pancreas 

 maximum proteolysis is observed in acid medium, and only slight 

 proteolysis in neutral. In all portions of pancreas coming in con- 

 tact with alkali, proteolysis has been paralyzed. This is especially 

 marked in that portion of pancreas pretreated with 0.2 per cent, 

 sodium hydrate. 



