

BLOODVESSELS OF THE ACINOUS GLANDS. 591 



distributed as in those of the intestine (to the description of 

 which the reader is referred), except that their diameter is 

 somewhat greater. But where the adenoid substance is dif- 

 fused, the vascular plexus is quite irregular. The veins issuing 

 from it are very numerous, and form short broad vessels, which 

 for the most part run in the intermediate spaces of the adenoid 

 substance, as well as immediately beneath the fibrous invest- 

 ment, from which they finally emerge a t various points. 



Arterial branches also pass towards the mucous membrane, 

 covering the sacculi internally, running up the interspaces 

 between the follicles, or traversing the layers of adenoid sub- 

 stance, and finally terminating in flat capillary loops, which 

 supply the papillae. From these large venous trunks arise, 

 which unite with those originally in the adenoid substance. 



The bloodvessels in the several follicles of the tonsils exhibit 

 the same relations ; the larger arterial and venous trunks run- 

 ning and branching between them. 



ACINOUS GLANDS OF THE ALIMENTARY CANAL. 



All the various glands of the digestive tract present an es- 

 sentially similar arrangement of their bloodvessels ; as may be 

 seen in the mucous glands of the mouth, pharynx, and oeso- 

 phagus, the salivary glands and pancreas, and the glands of 

 Brunner in the duodenum. The larger bloodvessels distributed 

 to these glands ramify in the connective tissui investing the 

 lobules. A single arteriole and veinlet penetrate each of the 

 smallest follicles, then break up in a tree-like manner, and are 

 finally lost in the capillary plexus. The capillary plexus 

 everywhere consists of arched, frequently branched tubules ; 

 with a mean diameter of O008 of a millimeter, which are so 

 arranged around the glandular vesicles that each of the latter 

 is surrounded by from two to four such arches. These vessels 

 communicate uninterruptedly throughout the entire lobule ; 

 each lobule thus possesses its own circumscribed capillary 

 system. A round-meshed capillary plexus invests the excre- 

 tory ducts of the mucous follicles as far as their orifice ; the 

 ducts are also accompanied by two veins which here and there 

 communicate, and near the surface of the mucous membrane 



