192 



LYMPHATIC SYSTEM. 



The lymphatics or lacteals which enter a gland arc named inferent or 

 afferent vessels {vasa infermiia sen affereniia), and those which issue 

 from it efferent vessels {vasa efferenUa). The afferent vessels (fig. 128, 



FiLC. 123. 



Fig. 12S.— DiAGRAMM.lTIC SECTION OP LYMPHATIC GlAND. 



a, I, affei'ent ; c, I, efferent lymphatics. C, cortical substance. M, reticulating cords 

 of medullary substance. /, s, lyniph-sinus ; c, fibrous coat sending ti'abcculffi, tr, into 

 the substance of the gland. 



a, I), on appi'o aching a gland, divide into many small branches, which 

 enter the gland ; the efferent vessels commonly leave the gland in 

 form of small branches, and at a little distance beyond it, or sometimes 

 even before issuing from it, unite into one or more trunks (e, l), usually 

 larger in size but fewer in number than those of the afferent vessels. 



The internal structure of hanphatic glands has been long a subject 

 of inquiry. Hewson considered that a lymphatic gland essentially con- 

 sists of a network of finely-divided lymphatic vessels, on and between 

 which capillary blood-vessels are ramified ; the whole being gathered 

 up and compacted into a comparatively dense mass by connective tissue, 

 which at the surface of the gland forms for it an enclosing capsule. The 

 afferent and efferent vessels are, according to Hewson, continuous with 

 each other within the gland, and the cellular cavities described as inter- 

 vening between them and serving as the medium of their communication, 

 were held by him to be nothing more than partial dilatations of some 

 branches of the common connecting plexus. 



Hewson's view of the constitution of the l3-mphatic glands was, until 

 lately, accepted by most anatomists ; but modern researches have 

 shown that the structure of these bodies is more complex. The fol- 



