FUNCTIONS OF THE INTESTINES. 



311 



ures therein and according to their individual functions. To 

 emphasize the histological similarity between the stomach and 

 intestines referred to, the following description of the arterial 

 and nervous supplies, from the pen of Professor Piersol, is 

 submitted: "The blood-vessels supplying the intestines follow 

 the general arrangement of those of the stomach. The larger 

 vessels pierce the serous and muscular coats, giving off slender 

 twigs to supply the tissues of the tunics; upon reaching the 

 submucosa the vessels form a wide-meshed net-work. Numer- 

 ous branches then pass through the muscularis mucosae, to be 

 distributed to the deeper as well as to the more superficial 

 parts of the mucosa; narrow capillaries form net-works which 

 surround the tubular glands, while beneath the epithelium wider 

 capillaries encircle the mouths of the follicles. From this 

 superficial capillary net-work the veins arise and, passing be- 

 tween the follicles, join the deeper venous plexus, which, in 

 turn, empties into the larger vein of the submucosa. In those 

 parts of the intestine where villi exist special additional arteries 

 pass directly to the bases of the villi, when they expand into 

 capillary net-works, which run beneath the epithelium and 

 around the central lacteal as far as the ends of the villi. These 

 capillaries terminate in venous stems, which descend almost 

 perpendicularly into the mucosa, in their course receiving the 

 superficial capillaries encircling the glandular ducts. Brun- 

 ner's glands and the solitary and agminated follicles are sup- 

 plied from the submucosa by vessels which terminate in capil- 

 lary net-works distributed to the acini of the glands and to the 

 interior of the lymph-follicles." . . . "The nerves distrib- 

 uted to the intestines are arranged almost identically to those 

 of the stomach; they are composed largely of non-medullated 

 fibers, derived from the trunks which pass within the mesen- 

 tery from the larger abdominal sympathetic plexuses. After 

 giving off branches to the serous coat, the nerves pierce the 

 longitudinal muscular tunic to form the rich intramuscular 

 plexus of Auerbach. This is composed of a rich net-work of 

 delicate, pale fibers, at the nodal points of which microscopical 

 ganglia exist; after supplying the longitudinal and outer part 

 of the circular muscular coats the fibers obliquely pierce the 

 latter tunic to gain the submucous tissue, where they form the 



