Digestion. 123 



granular, and nucleated ; those which line the lumen of 

 the gland are called the principal cells. Scattered amongst 

 the principal cells, but existing in larger numbers at the neck 

 of the gland than at its base, are found certain large cells 

 (oval, granular, and nucleated), which from their position 

 relative to the lumen of the gland are called parietal, 

 marginal, or border cells. These cells are distinctive of 

 the fundus glands, and they stain readily with aniline blue. 



The pyloric gland has below its neck but one variety of 

 cell — viz., the cylindrical — containing a nucleus at its 

 attached edge. The duct is lined above the neck by the 

 ordinary epithelium of the stomach, and the same remark 

 applies to the cardiac glands ; it is from this epithelium 

 that the mucus is secreted. Lying deep in the mucous 

 membrane of the stomach between the gastric glands may 

 be found large mucus secreting glands, which, doubtless, 

 contribute to the formation of the remarkable amount of 

 mucin found in the stomach of the horse. 



The difference in the structure of the follicular glands of 

 the stomach depends upon their function. The important 

 distinction between the fundus gland with its principal and 

 parietal cells, and the pyloric gland with its principal cells 

 only, is that the former secretes both the pepsin and acid 

 of the gastric juice, the acid being separated from the 

 blood, or secreted, by the parietal cells, whilst the pepsin 

 only is formed by the principal cells ; the pyloric glands, 

 on the contrary, only secrete pepsin and no acid. 



Ellenberger states that he has found fundus glands in 

 the pyloric region. 



We have previously mentioned that the cells of the 

 salivary glands undergo certain changes in appearance, the 

 result of rest and activity ; the same remark applies to the 

 gastric follicles. These changes have been worked out by 

 Heidenhain and Langley. The former found that the large 

 marginal cells of the fundus glands during activity — viz., 

 digestion — bulged from the side of the gland and en- 

 croached on the lumen, and also became much larger than 

 ordinary ; the principal cells of the gland were found as 



