244 THE INCOME OF ENERGY 



little trypsin and had a correspondingly slight 

 action on proteids. When intestinal juice was 

 added to this pancreatic juice, the pancreatic 

 juice at once became active in proteid digestion. 

 Pawlow called the activating body enterokinase. 1 

 In 1902, Delezenne and Frouin 2 found that 

 pancreatic juice obtained by catheterizing the 

 pancreatic duct contained no trypsin whatever; 

 their procedure prevented any contact between 

 the juice and the intestinal mucous membrane 

 at the orifice of the pancreatic duct. It has been 

 shown that enterokinase is a ferment, secreted 

 in the small intestine, and that it converts tryp- 

 sinogen contained in pure pancreatic juice into 

 trypsin, the active proteid ferment. 



Preparation of Enterokinase. Scrape lightly 

 with the handle of a scalpel the upper part of 

 the mucous membrane of the small intestine 

 (dog or cat). Digest the scrapings during two 

 days in a closed vessel of water to which a few 

 drops of chloroform have been added to prevent de- 

 composition. Filter through paper, then through 

 a Berkefeldt filter. The resulting solution is 

 perfectly clear, contains a certain amount of 

 coagulable proteid, and will- retain its activity 



1 PAWLOW : The Work of the Digestive Glands, translated 

 by W. H. Thompson, 1902, p. 160. 



2 DELEZENNE and FROUIN : Comptes rendus de la societe 

 de biologic, Paris, 1902, pp. 691-693. 



