286 THE DIGESTIVE ORGANS. 



of similar canals. Numerous lymph-vessels from this network 

 penetrate the mucous membrane in a vertical direction, uniting at 

 the bases of the intestinal glands to form a second plexus sub- 

 glandular plexus of the mucosa. A few of the lymph-vessels pene- 

 trating the mucous membrane directly perforate the muscularis 

 mucosae to join the lymphatic network of the submucosa. The 

 subglandular plexus also communicates with the submucous 

 lymphatic plexus by means of small radiating branches (vid. Fig. 

 224). The solitary lymph-nodules themselves contain no lymphatic 

 vessels, but are encircled at their periphery by a network of lymph 

 capillaries. The same is true of the nodules in Peyer's patches. 

 It is an interesting fact that in the rabbit lymph-sinuses exist 

 around Peyer's patches, giving to the latter a still greater similarity 

 to the nodules of lymph-glands. The solitary nodules of the same 



Fig. 225. A portion of the plexus of Auerbach from stomach of cat, stained with 

 methylene-blue (infra vitani), as seen under low magnification. 



animal are not surrounded by the sinuses just mentioned (Stohr, 



94)- 



The structures of the alimentary canal receive their innervation 

 mainly from sympathetic neurones, the cell-bodies of which are 

 grouped to form small ganglia, located at the nodal points of two 

 plexuses, one of which is situated between the two layers of the 

 muscular coat, the other in the submucosa. These two plexuses 

 are found in the entire digestive tract, although not equally well 

 developed in its different regions. The outer plexus, the more 

 prominent of the two, situated between the two layers of the muscu- 

 lar coat, is known as the plexus myentericus, or the plexus of Auer- 

 bach. It consists of innumerable small sympathetic ganglia, united 

 by small bundles of nonmedullated fibers, containing here and there 

 a much smaller number of medullated nerve-fibers. The cell-bodies 

 of the sympathetic neurones of this plexus are grouped to form the 



