THE FOOD AND DIGESTION 



337 



Probably the C0 2 liberated in the cells seizes on some of the 

 Na and turns out HC1. 



The Pepsin and Rennin are produced in the chief or peptic 

 cells which line the glands both of the cardiac and pyloric 

 parts of the stomach. During fasting granules, are seen to 

 accumulate in these cells, and when the stomach is active 

 they are discharged. These granules are not pepsin but the 

 forerunner of pepsin pepsinogen. 



(/) Influence of Various Diets upon the Gastric Juice. 

 This has been chiefly worked out by Pawlow on dogs. By a 



FIG. 148. Diagram of Pawlow's Pouch made on the Stomach of a Dog. 



longitudinal incision along the great curvature of the stomach 

 he separated a V-shaped piece (Fig. 148). The cut edges of 

 the stomach are then stitched up and the sides of the 

 V-shaped portion are also united, except that at the apex they 

 are attached to the skin surface. The mucous membrane 

 between the stomach cavity and the " pouch " formed is then 

 united, and a small stomach is thus produced, still connected 

 with the nerves and vessels, but separated from the main 

 cavity and pouring its contents on to the surface. Any 

 modification in the secretion of the stomach is indicated by 

 a modification in the secretion from this pouch. 



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