106 CHARACTERS OF ACTIVE AND RESTING GLANDS. [BOOK II. 



said that a considerable histological resemblance exists between the 

 pyloric epithelial cells and the central cells of the fundus, the one 

 form passing by transitions into the other; and a large number of 

 facts indicate that the resemblance in structure is accompanied by an 

 essential identity in the processes which have their seat in them. 



HISTOLOGICAL CHARACTERS OF THE GASTRIC GLANDS DURING 

 FASTING AND DIGESTION, AND RELATION OF THESE TO THE 

 AMOUNT OF PEPSIN PRESENT. 



Our knowledge of the changes which the secretory epithelium 

 cells of the gastric glands undergo during digestion, or rather the 

 appearances which they present during abstinence from food and at 

 various stages of the digestive process, is derived from the researches 

 of Grutzner and Heidenhain who have studied the glands after they 

 have been hardened in alcohol, and from those of Langley and Sewall 

 who have traced the changes in the living glands. 



Taking the case of the glands hardened in alcohol first, it is 

 found that the central cells of the cardiac glands and the deeper 

 cells of the pyloric glands, after long abstinence from food are some- 

 what swollen, pale, finely granular, and do not stain readily. During 

 the early stages of digestion the cells appear somewhat larger, more 

 granular and more easily stained ; whilst at the close of the digestive 

 process the cells are much diminished in size, as it were shrunken, 

 and are stained much more deeply than during the early stages. 



From Langley and Sewall's observations of the fresh and living 

 glands, unacted upon by reagents, we know that after long abstinence 

 the cells are studded with granules, which diminish during the act 

 of secretion, and collect near the lumen, the outer zone of the cell 

 appearing clear. The granules are most abundant in those regions 

 of the stomach in which the amount of pepsin is found to be largest. 

 From these facts it is concluded that " the conspicuous granules in 

 the chief cells are directly connected with the formation of ferment 1 ." 

 According to this view, which has also been adopted by Nussbaum, 

 the changes in the gastric glands closely resemble the changes which 

 occur in the pancreas. 



Grtitzn r' Griitzner, and after him Langley and Sewall, have 



curves repre- endeavoured to ascertain the relative amounts of pepsin 

 senting the present in the stomach at varying times, and the former 

 fluctuations in observer has expressed his results in the form of the 

 the amount of curves w hich are appended (p. 108), and which exhibit the 

 mucous "nJm- variations in the amount of pepsin present in the mu- 

 Drane of the cous membrane of the fundus and of the pylorus during 

 fundus and abstinence and in successive hours following digestion, 

 pylorus. T ne equal numbered intervals in the abscissa-line 



1 J. N. Langley and H. Sewall, ' On the Changes in Pepsin-forming Glands during 

 Secretion.' Journal of Physiology, Vol. u. pp. 81 et seq. 



