THE SECRETION OF THE DIGESTIVE JUICES 



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The chief cells of the oxyntic, and the similar if not identical cells 

 of the pyloric glands, are believed to manufacture the pepsin-form- 

 ing substance. The ovoid cells of the former are supposed to secrete 

 the hydrochloric acid. The evidence on which this belief is based 

 is as follows: 



The glands of the antrum pylori in the dog, in which in most 

 situations no ovoid cells are to be seen, secrete pepsin, but no acid. 

 The pyloric end of the stomach or a portion of it has been isolated, 



Fig- I 57- The Gastric Glands (Ebstein). On the left, oxyntic; right, pyloric. 



the continuity of the alimentary canal restored by sutures, and the 

 secretion of the pyloric pocket collected. It was found to be alka- 

 line, and contained pepsin. The glands of the frog's oesophagus, 

 which contain only chief cells, secrete pepsin, but no acid. It seems 

 fair to conclude that the chief cells of the fundus glands in the 

 mammal secrete none of the free hydrochloric acid, but certainly 

 some of pepsin. But it does not follow that all the pepsin is formed 

 by these cells, although it would seem that all the hydrochloric acid 



