INTESTINAL JUICE 387 



24. Intestinal Juice. The secretion of the mucous membrane of the 

 small intestine has been proven to have a weak digestive action on pro- 

 teins and perhaps on starches. It can be obtained from an intestinal fistula. 

 Its chief digestive importance consists in the presence of the activating 

 enzyme, enterokinase. Enterokinase can be prepared by extracting the 

 mucous membrane of the small intestine by the method outlined for making a 

 pancreatic extract. 



To two test-tubes containing 5 c.c. of artificial pancreatic juice, or pref- 

 erably containing secretin pancreatic juice, add flocks of fibrin. Keep one 

 for the control, to the other add 2 c.c. of enterokinase solution. The test- 

 tube containing enterokinase will digest more rapidly and more effectively 

 than the other. 



