THE STOMACH AND INTESTINE. 



285 



down between the glands, and are arranged in the form of a net- 

 work just above the muscularis mucosae, but with coarser meshes 

 than that formed by the blood-vessels. Here the valves begin to 

 make their appearance. The lymph-vessels pass through the mus- 

 cularis mucosae and in the outer portion of the submucosa form a 

 plexus with open meshes, from which are derived the efferent ves- 

 sels which penetrate the muscular coat and thus gain access to the 

 mesentery. In their course through the muscular coat they com- 

 municate with the branches of a plexus of lymph -vessels situated 

 between the two muscular layers, and also with lymph-vessels found 

 in the serous coat. 



Epithelium 

 of villus. 



Central chyle- 

 vessel of vil- 

 lus. 



Vein. 



Fig. 224. Schematic transverse section of the human small intestine (after F. P. Mall). 



The lymphatics of the small intestine begin in the axes of th'e 

 villi. When filled, these lymph-vessels are conspicuous, irregularly 

 cylindric capillary tubules, lined by endothelial cells, and known as 

 the axial canals, the chyle-vessels, or the lacteals of the villi. They 

 are hardly discernible when collapsed. If the villus be broad, it 

 may contain two chyle-vessels, which then join at the apex of the 

 villus, and may also be connected with each other by a few anasto- 

 moses. At the base of the villus the chyle-vessel enters a lymphatic 

 capillary network, the structure of which is due to the confluence 



