34 PROTEOLYTIC PANCREATIC FERMENT 



about as it is drunk, quite naturally suggesting comparison 

 with Baron Miinchhausen's well known horse, with all its 

 drinking merely pouring out the water from the cut which 

 has severed away the posterior half of its body. But if, 

 instead of water, acid gastric contents come in contact with 

 the duodenal mucous membrane, there at once occurs a reflex 

 closure of the pylorus. In this way the intestine is protected 

 from further flooding with acid gastric material. At the 

 same time entrance of alkaline digestive fluids (the bile, 

 pancreatic juice and intestinal juice) into the duodenum is 

 brought about by the acid material, these juices neutralizing 

 the acid, As soon as the pylorus opens again another charge 

 of acid is expelled into the duodenum ; and the same perform- 

 ance automatically repeats itself. According to Cannon 

 reflex relaxation is induced directly by contact of the acid 

 chyme upon the pars pylorica. Besides the influence of 

 acid from the intestine, closure of the plorus may be 

 caused by fat; and according to the studies of 0. Cohn- 

 heim and his associates it is not a matter of consequence 

 where the oil or acid is placed in the small intestine. From 

 the fact that cocainizing the intestine prevents the contrac- 

 tion the reflex nature of the act cannot be in doubt. There 

 are, too, in all probability a number of other factors involved 

 in the regular discharge of the gastric contents besides the 

 hydrochloric acid and the fat of the chyme, especially the 

 consistence of the food. 



Passage of the Intestinal Contents into the Stomach. In 

 contrast, a matter of physiological interest, first brought to 

 attention within the past few years, is that of the entrance of 

 intestinal contents into the stomach, observed by Pawlow and 

 Boldyreff. After the introduction of fatty foods particu- 

 larly, but sometimes also after fasting, and, too, when there is 

 an especially high degree of gastric acidity, it may happen 

 that a mixture of intestinal secretion, pancreatic juice and 

 bile regurgitates into the stomach to such an extent that the 

 hydrochloric acid of the stomach may be neutralized and 



