DIGESTION. 175 



II. The Glands of the Mucous Membrane of the Stomach, 

 and the Gastric Juice. 



Since of old, the glands of the mucous coat of the stomach have 

 been divided into two distinct kinds. The kind occurring in 

 the greatest abundance, and the most important in size, especially 

 in the fundus, has been named fundus glands, also RENNET or 

 PEPTONE glands. The other, which is found in the neigh- 

 borhood of the pylorus, has received the name of pyloric glands, 

 sometimes also, though incorrectly, mucous glands. The mucous 

 coating of the stomach is covered to its entire extent with a layer 

 of cylindrical epithelium, which is considered as consisting exclu- 

 sively of follicles, small cup-shaped cavities which by a mucus-like 

 metamorphosis produce the protoplasm. 



The fundus glands contain two kinds of cells: ADELOMOR- 

 PHIC or principal cells, and DELOMORPHIC or PARIETAL cells, the 

 latter formerly called RENNET or pepsin cells. Both kinds 

 consist of protoplasm rich in proteids; but their relationship 

 to coloring matters seems to show that the two albuminous bodies 

 are not identical. The nucleus must consist chiefly of nuclein. 

 Besides the above-mentioned constituents the fundus glands con- 

 tain as more specific constituents two zymogens, which are the 

 mother-substances of the pepsin and the rennet, besides a small 

 quantity of fat and cholesterin. 



The pyloric glands contain cells which are generally considered 

 as related to the above-mentioned chief cells of the fundus glands. 

 As these glands were formerly thought to contain a larger quantity 

 of mucin, they were also called mucous glands. According to 

 HEIDENHAIN, independent of the cylindrical epithelium of the 

 excretory passages, they take no part worthy of mention in the 

 formation of mucus, which, according to his views, is effected by 

 the epithelium covering the mucous membrane. The pyloric 

 glands also seem to contain the zymogens referred to above. Alkali 

 chlorides, alkali phosphates, and calcium phosphates are found in 

 the mucous coating of the stomach. 



The Gastric Juice. The experiments of HELM and BEAUMONT 

 on persons with gastric fistula led to the suggestion that gastric 

 fistulas be made on animals, and this operation was first performed 



