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CHAPTER VII. 



ON THE LYMPHATICS. 



THE lymphatic vessels, or absorbents, have received their double 

 appellation from certain phenomena which they present ; the former 

 name being derivable from the appearance of the limpid fluid (lympha, 

 water) which they convey ; and the latter, from their supposed pro- 

 perty of absorbing foreign substances into the system. They are 

 minute, delicate, and transparent vessels, remarkable for their gene- 

 ral uniformity of size, for a knotted appearance which is due to the 

 presence of numerous valves, for the frequent dichotomous divisions 

 which occur in their course, and for their division into several branches 

 immediately before entering a gland. Their office is to collect the 

 products of digestion and the detrita of nutrition, and convey them 

 into the venous circulation near to the heart. 



Lymphatic vessels commence in a delicate network which is distri 

 buted upon the cutaneous surface of the body, upon the various 

 surfaces of organs and throughout their internal structure ; and from 

 this network the lymphatic vessels proceed, nearly in straight lines, in 

 a direction towards the root of the neck. In their course they are in- 

 tercepted by numerous small spheroid or oblong bodies, more or less 

 flattened on their surface, lymphatic glands. The lymphatic vessels 

 entering these glands are termed vasa inferentia or afferentia, and those 

 which quit them vasa efferentia. The vasa inferentia vary in number 

 from two to six, they divide at the distance of a few lines from the 

 gland into several smaller vessels and enter it by one of the flattened 

 surfaces.* The vasa efferentia escape from the gland on the opposite, 

 but not unfrequently on the same surface ; they consist like the vasa 

 inferentia at their junction with the gland of several small vessels 

 which unite after a course of a few lines to form from one to three 

 trunks, often twice as large as the vasa inferentia. 



Lymphatic vessels admit of a threefold division into superficial, 

 deep, and lacteals. The superficial lymphatic vessels, upon the surface 

 of the body, follow the course of the veins, and pierce the deep fascia 

 in convenient situations, to join the deep lymphatics. Upon the sur- 

 face of organs they converge to the nearest lymphatic trunks. The 

 superficial lymphatic glands are placed in the most protected situations 



* See Mr. Lane's article on the "Lymphatic System," in the Cyclopaedia of 

 Anatomy and Physiology. 



