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A MANUAL OF PHYSIOLOGY 



alkaline, and contained pepsin. The glands of the frog's oeso- 

 phagus, which contain only chief cells, secrete pepsin, but no acid. 

 It seems fair to conclude that the chief cells of the fundus glands 

 in the mammal secrete none of the free hydrochloric acid, but 

 certainly some of pepsin. But it does not follow that all the pep- 

 sin is formed by these cells, although it would seem that all the 

 hydrochloric acid must be secreted by the only other glandular 



FIG. 140. THE GASTRIC GLANDS (EBSTEIN). 

 On the left, oxyntic ; right, pyloric. 



elements present, the ovoid or ' border ' cells. And, indeed, the 

 glands in the fundus of the frog's stomach, which are composed 

 only of ovoid cells, whilst secreting much acid, also form some 

 pepsin, although far less than the cesophageal glands. During 

 winter sleep (in the marmot) the production of hydrochloric 

 acid in the parietal cells stops altogether, while the chief cells 

 continue to accumulate granules of pepsinogen. 



