DIGESTIVE SYSTEM. 205 



the superior to form the portal vein. This blood 

 thus ultimately passes through the liver. 



Lymphatics of the Alimentary Canal. The lym- 

 phatics begin in the mucosa just beneath the epithe- 

 lium. In the small intestine they begin with the cen- 

 tral lymph vessel of a villus. These vessels form a 

 network in the deeper portion of the mucosa and 

 then pass through the muscularis mucosa to form 



Fig. 153. A portion of the plexus of Auerbach from stomach of 

 cat, stained with methylene-blue (intra vitam), as seen under low mag- 

 nification (Huber). 



an extensive loose plexus in the submucosa. Coarser 

 lymphatic vessels lead from this plexus through 

 the muscularis, where branches are received from a 

 lymphatic plexus located between the two muscle 

 coats. 



The solitary lymph nodes of the mucosa contain 

 no lymphatics, but are encircled at their periphery 



