210 ROBERT K. S. IJM 



is also pr()l)tibly true; for animals other than the cat, since the 

 peptic cells are invariably found in the deep or blind end of the 

 tubule, which may be considered to have d(n' eloped last. 

 This encourages the view that the mucoid cell gives rise to the 

 peptic cell, without suggesting that the latter is merely a func- 

 tional phase of the former. Mucoid and peptic cells are 

 undoubtedly different functionally and structurally. In this 

 connexion it is noteworthy that mitoses have never been 

 observed in peptic cells, while they have been seen in mucoid 

 and more frequently in oxyntic cells. In short the mucoid cell 

 is a stage in the genesis of the peptic cell. Transitions from the 

 one state to the other are difificult to demonstrate, but con- 

 sidering the differences, slight though they may be, which occur 

 in the mucoid cells of the same and of different animals, and 

 especially the occurrence of the basal ' red-staining ', the gap 

 in the genesis of the peptic cell is perhaps partially filled. 

 Looked at in this light, the observation of Cade on the retro- 

 gression of the peptic cells in the vicinity of gastero-enterostomy 

 openings (see Cade (2) and Part II of this paper) may be 

 translated as the inhibition of ])eptic cell-formation and the 

 arrest of its genesis in the mucoid stage. 



Utilizing the above hypothesis, the cells of the cardiac and 

 pyloric glands may be regarded as cells w^hich have been 

 prevented from attaining full development by the conditions 

 existing at the orifices of the stomach. 



The relationship between the \'arious gastric cells maj- 

 therefore be classified as follows. The mucoid cell of the fundus 

 forms the lowest functional type, for it apparently does not 

 secrete pepsin. The cardiac and pyloric cells are a little more 

 advanced, since Klemensiewicz (4) and Heidenhain (3) have 

 shown that the pyloric region secretes a proteolytic ferment. 

 Structurally these cells show the basal ' red-staining ' more 

 constantly (especially in the rabbit) than the mucoid cell, and 

 this may be taken as indicating a certain degree of zymogen 

 formation. The cardiac cells may not function exactly as the 

 pyloric cells do, but they are at least cells of the same develop- 

 mental order, and thev constitute such a small element in the 



