SECT. 2l8.] VESSELS IN THE LYMPHATIC GLANDS. 



509 



Fig. 209. 



fcrcnt lymphatic vessels, I would further remark, that all our 

 knowledge of this subject leads us to regard the outermost and 

 most sharply defined alveoli as being less frequently and less 

 directly connected with the vasa inferential than those which are 

 situated in the more internal parts of the medulla. At least in 

 the mesenteric glands, both of man and animals, at the period of 

 absorption, when all the inferent vessels contain a whitish juice, 

 the outermost alveoli are seen not to be milk-white, but of their 

 ordinary grey colour, while the inner parts are frequently whitish 

 throughout. To this condition, however, more recent observations 

 have taught me that there are exceptions, for I have seen two 

 cases in man, in which the mesenteric glands were coloured milk- 

 white quite equally on the surface and medulla, the colour being 

 in patches of various sizes. When, moreover, it is considered, that 

 in injections of the vasa infercntia, even the outermost alveoli 

 become filled, we cannot resist the assumption, that they do really 

 communicate with those vessels. 



It is relatively easy to follow 

 the lymphatic vessels in the me- 

 dullary substance. Even with 

 the naked eye, sections of this 

 substance exhibit, besides blood- 

 vessels, a spongy tissue, from 

 which, in the fresh gland, we 

 may readily press out small drops 

 of fluid, which is either milky or 

 serous, according as the gland 

 contains chyle or lymph. In- 

 jections, too, particularly from 

 the vasa efferentia, or fine sec- 

 tions microscopically examined, distinctly show that the medul- 

 lary substance consists for the most part of a dense plexus of 

 coarser and finer lymphatics, which, at least in the number of 

 of their anastomoses, resemble the vascular system of the corpora 

 cavernosa. This spongy tissue, however, is very essentially dis- 

 tinguished from that of the sexual organs, by the circumstance 

 that the lymphatics composing it are all provided with special 

 coats, and can even be isolated, at least in part, from the stroma 

 of connective tissue which supports them. The more intimate 

 condition of the lymphatic plexus of the medullary substance is as 

 follows : Emerging everywhere in great numbers from the inner 

 parts of the cortex, fine lymphatic vessels enter the medulla, and 

 immediately anastomose freely with each other, and become 



Transverse section of the mesenteric gland 

 of the ox, magnified 8 times, a. hilus of the 

 gland; b. medullary substance, with fine net- 

 works of lymphatic vessels; c. cortical sub- 

 stance, with indistinct alveoli ; d. envelope of the 

 organ. 



