MECHANISM OF SECKETION OF GASTRIC, 

 PANCREATIC, AND INTESTINAL JUICES. 



By J. S. EDKINS. 



CONTENTS. Histological Appearances of tlie Secretory Conditions of the Stomach, 

 p. 531 Functions of the Cells and Regions of the Stomach, p. 532 Methods 

 of obtaining Gastric Juice, p. 536 Influence of the Nervous System on Gastric 

 Secretion, p. 537 Conditions which provoke Secretion, p. 540 Formation of 

 the Ferments of Gastric Juice, p. 542 Formation of Rennin, p. 543 Variations 

 in Gastric Juice during Digestion, p. 544 Histological Appearances of the 

 Secretory Conditions of the Pancreas, p. 546 Influence of the Nervous System 

 upon Pancreatic Secretion, p. 547 Conditions which provoke the Flow of 

 Pancreatic Juice, p. 551 Ferments of the Pancreatic Juice and their Ante- 

 cedents, p. 551 Variations in Pancreatic Juice during Digestion, p. 553 

 Evidence of Secretion in the Intestine, p. 554. 



THE MECHANISM OF GASTRIC SECRETION. 



The histological appearances of the different secretory con- 

 ditions of the stomach, and the relation of the secretory granules 

 to the enzyme. Though the existence of specific granules in secretory 

 glands had previously been pointed out in connection with the pancreas 

 and some salivary glands, it was not till 1879 that their existence was 

 also observed in the secreting cells of the gastric mucous membrane by 

 Langley and Sewall, 1 who showed that the chief or central cells are, in 

 the resting condition, crowded with conspicuous granules, and that 

 during digestion the granules in these cells diminish. As far as the 

 ovoid or border cells are concerned, granules are to be seen in these, but 

 they are much smaller in size, though quite discrete. 



After digestion the cells take on different appearances, which consist 

 mainly in the decrease of the number of granules. This decrease may 

 be manifested in two different ways. In the first case, and the more 

 typical, the outer border of the cell alone may show the lack of granules, 

 the luminal border retaining them, unless in an extreme condition of 

 exhaustion. In the second case, there may be a uniform decrease of 

 granules throughout the cell, accompanied by a diminution in size 

 of the cell, but unaccompanied by any formation of zones. These two 

 forms of decrease may occur in different parts of the gastric mucous 

 membrane of the same animal. Thus in the greater curvature of the 

 stomach in both the rabbit and guinea-pig there is a formation of zones, 

 in the cells of the fundus such a division is not seen. 



1 "Changes in Pepsin -forming Glands," Journ. PhysioL, Cambridge and London, 1879, 

 vol. ii. 



