144 NORMAL HISTOLOGY. 



to the axis of the canal. In certain parts of the 

 stomach an indistinct third layer is found, in which 

 the cells have an oblique course. Inside of the 

 muscularis and joining it to the mucosa, is a layer of 

 loose fibrillar connective tissue, called the submucosa y 

 in which the blood and lymphatic vessels ramify. 

 In the mucosa, finally, we have a delicate support- 

 ing framework of connective tissue, varying some- 

 what in its structure and abundance in different 

 parts of the canal ; this is covered by epithelial 

 cells and contains the grandular apparatus, while at 

 the base of the glands and adjacent to the submu- 

 cosa is a thin layer of smooth muscle-cells, lying in 

 both transverse and oblique directions, called the 

 muscularis mucosce, from which usually a few muscle- 

 cells pass up between the glands. 



The chief differences in minute structure between 

 the stomach and intestines are in the mucous mem- 

 brane, and since in this the glands are very impor- 

 tant factors, a word should be said here about the 

 structure of glands in general. 



Although the term gland is popularly applied to 

 structures having the greatest diversity of form and 

 function, and little in common but their name, we 

 mean by it here, those organs whose physiological 

 activity expresses itself, in part at least, by the 

 elaboration of certain specific fluids, secretions, or 

 excretions. All such glands have a somewhat analo- 

 gous structure, and present two distinct kinds of 



