184 BIOLOGY. [Book ii. 



is specially entrusted with this acid secretion. Thus the 

 stomachal juice is alkaline in the paunch and the bonnet of 

 ruminants : it is acid, on the contrary, in the caillette. 



In the mammifers, provided as man is, with a single stomachal 

 pouch, the differentiation, which no longer exists in the general 

 form of the stomach, continues in its apparatus of secretion. 

 The innumerable glandules of the stomachal mucous membrane 

 have not then the same function, and we can determine approxi- 

 matively what region of the stomach secretes acid mucus, what 

 other secretes fermented mucus, or peptic mucus. 



In effect, if we subject to hot infusion in acidulated water 

 the stomach of a mammifer, a part of the stom^ach disappears 

 at tjie end of an hour or an hour-and-a-half : it is disaggregated 

 first and liquefied afterwards. The other part, which is always 

 the pyloric region, dissolves only with extreme tardiness. The 

 part easily dissolved has probably the office of secreting the acid 

 mucus.' The anatomical examination of the glandules in the 

 one region and the other confii-ms this view. The glands of 

 the region supposed to be peptic are almost always ramified 

 into two or three small conduits interiorly lined with cells 

 of cylindrical epithelium, but filled in the recesses by cells of 

 globulous epithelium. These are the secreting cells, and we find 

 their analogues in the caillette of the ruminants. The glands 

 probably mucous are more rarely ramified, and do not contain 

 cells of globular epithelium. "We have seen that the mucous 

 glamds occupy especially the pyloric region of the stomach : as 

 to the peptic glands they are especially abundant in the middle 

 region. 



The globular cells contained in the cul-de-sac of the peptic 

 glands secrete during stomachal digestion a mucus, holding in 

 solution a faint albuminoidal ferment, which has been called 

 pepsine. According to M. Schitf pepsine is not secreted at the 

 expense of the elements of the blood, except when this fluid is 

 previously charged with substances which he calls peptogem. 

 ^ M. Sohiff, loc. cit., t. U., p. 238. 



