378 Grant Sherman Hopkins 



According to Schultze (20), the epithelial cells of the stomach 

 in all vertebrates, are open, i. e., the free ends of the cells are 

 not covered by a cell-wall. He thinks that the mucus which 

 these cells secrete is for the purpose of protecting the cells 

 themselves from the digestive action of the secreted fluids. 

 Brinton (3), also seems to hold the same view. He says, "The 

 protection of the stomach from its own secretion is effected 

 mainly by the salivary and other ^secretions which enter it 

 from the cesophagus and the duodenum .... For units of 

 mucous membrane. Fishes seem to have the most powerful 

 gastric digestion." These .statements appear somewhat un- 

 satisfactory from the fact that in the American Ganoids, at 

 least, the ciliated character of the epithelium would tend 

 strongly to preclude the formation of a distinct mucous coat 

 over the surface of the stomach. But apart from this, it is 

 believed that the vital properties of the cells are sufficiently 

 potent to withstand any deleterious effects which the gastric 

 secretions may possibly have upon them. Edinger (6), thinks 

 that the functions of the mucus are to thin the chyme and to 

 form a protective covering over the hard indigestible bodies, 

 as sand, shells, etc., which find their way into the stomach. 

 He says that such foreign bodies, surrounded by a tough mass 

 of mucous, are frequently found in the intestine. Ebstein (5), 

 found open as well as closed cells and is of the opinion that 

 during digestion the membrane of the closed cells is ruptured. 

 In all the specimens examined by the writer, both open and 

 closed cells were found. 



The surface epithelial cells of Amia's stomach are verj- 

 slender and the attached ends are continued into long thread- 

 like processes which intertwine with the subjacent mucosa. 

 As already stated, ciliated cells were found uninterruptedly 

 from the oesophagus to within about 2 c. m., of the pylorus ; 

 scattered among these were many open beaker-cells. From 

 the open end of many of the latter a mucous mass of var3'ing 

 size was often seen projecting some distance beyond the free 

 ends of the cells. At the cardiac end of the stomach, the 

 gastric glands appear as short tubes, at the base of the follicles 

 mentioned above ; they, however, rapidly increase in length. 



