238 



DIGESTIVE SYSTEM. 



The principal function of the epithelium of the stomach is 

 to throw out the products of secretion. In the first place, 

 this mucous coat, like all the others, supplies mucus by des- 

 quamation : this is generally found in flakes, because the 

 shedding of the epithelial cells is not complete ; but it 

 appears only in morbid, or, at least, abnormal cases, the nor- 

 mal gastric juice containing no mucus : those glands of the 

 stomach (identical with Lieberkiihn's glands) which have 



been called mucous glands, 

 have thus been incorrectly 

 named, the mucus not being 

 a normal product, and no 

 special gland being needed 

 to produce it. Since it is 

 the result of desquamation 

 of the entire free surface. 



The normal and charac- 

 teristic secretion of the 

 stomach is the gastric juice, 

 which is chiefly produced by 

 the glandular culs-de-sac of 

 the cardiac region. These 

 are distinguished from the 

 ordinary glands of Lieber- 

 kiihn (Fig. 65) by their 

 epithelium not being co- 

 lumnar, but polyhedral, at 

 least in the deeper portions 

 (Fig. 68). 1 This gastric 

 juice, produced by the shed- 

 ding or falling off from 

 these cellular elements, is a 

 very thin fluid, containing 

 scarcely four per cent of solid 

 matter, two-thirds of which consist of organic substances 



Fig. 68. Compound peptic gland.* 



shall see that such absorption is necessary to his theory of pepto- 

 genous substances, which we shall examine later. 



1 Large quantities of closed follicles (resembling those of the 

 intestine) recently have been presumably discovered in the stomach, 



* 1, Excretory tube, lined with a columnar epithelium resembling that of the 

 gastric mucous in general. 2, Culs de sac like the finger of a glove, filled with 

 large granular globules (cells of peptic secretion), the fragments of which are 

 thrown upon the gastric surface by the excretory tube which is filled with them. 

 (Kolliker.) 



