STRUCTUK'R OF THE MAMMALIAN GASTRIC GLANDS. 363 



proteolytic ferment, in Heidenhain's case even after the lapse 

 of five months. 



In his recent exhaustive compilation of the literature of 

 this subject, Oppel ^ attempts to reconcile the conflicting re- 

 sults of these two lines of research. He concludes that the 

 pyloric gland cells are cells sui generis, differing both from 

 the surface epithelium and from the chief cells, and engaged in 

 the secretion of pepsin holding gastric juice. 



The present state of our knowledge docs not permit of any 

 comparison between the pyloric glands and the other glands 

 of the stomach, nor is it possible to compare them with any of 

 the gastric glands of lower Vertebrates. 



Further, the researches of Edelmann- have shown that there 

 exists in the cardiac region of the stomach of many mammals 

 a peculiar kind of gland, called by him the cardiac gland, 

 differing both from the fundus glands and the pyloric glands, 

 and concerning which we are even more in the dark. 



The application of new methods to the study of the gastric 

 glands has convinced me that the pyloric and cardiac glands 

 of various animals are closely allied to one another, and that 

 the various kinds of cells one meets are but the results of 

 differentiation along divergent lines from a single primitive 

 type. The pyloric gland cells, furthermore, are in most 

 mammals closely allied to, and in the cat, dog, and rabbit 

 identical with, certain cells in the neck of the fundus gland, 

 which, up to the present, have been regarded as ordinary chief 

 cells. 



A convenient starting-point for the descriptions which 

 follow is afforded by the gastric glands of the frog. 



A fundus gland of this animal may be divided into three 

 portions; the duct or stomach pit, lined by mucus-secreting 

 cylindrical cells similar to those of the surface ; the neck, 

 occupied by very large vesicular-looking cells, which, although 

 different from the surface cells, are also regarded as mucous 

 cells, and the body of the gland, occupied by granular proto- 



1 ' Lehrbuch der vergleichenden niik. Anat.,' 1896. 

 ' 'Deutsch. Zeitschr. f. Thieniiediziii,' Bd. xv. 



