THE LYMPHATICS. 



693 



capillaries, could not be determined, and I should not, therefore, at pre- 

 sent definitely declare them to be pervious parts of the vascular system ; 

 whilst I have not the least hesitation, nevertheless, in referring them to 

 that system, for although they may have no canal, they scarcely admit 

 of any other possible interpretation, than as being derived from the vas- 

 cular plexus, which covers almost the entire cornea in the child at birth, 

 and as being obliterated capillaries. Should these corneal elements not 

 turn out to be vasa serosa, I am acquainted, in the adult, with no situa- 

 tion in which such vessels exist, whilst vessels conveying plas7na are 

 everywhere present during the development of the capillaries, as a pre- 

 liminary phenomenon {vid. infra), and it is therefore intelligible that, 

 even at a subsequent period, scattered vessels of the kind should occa- 

 sionally be met with, as in the brain of the Calf, according to Henle ; 

 or may perhaps exist in great quantity, just as in the distribution of the 

 nerves, the terminations often retain the embryonic character. 



3.— OF THE LYMPHATICS. 



§ 218. The lymphatics, except in their contents, correspond so closely 

 with the veins, that a short exposition of their structure will suffice. 



Fig. 288. 

 ) 



FlO. 2S8. — Capillary lymphatic from the tail of the Tadpole, magnified 350 diameters: a, 

 membrane; b, processes formed by it; c, remains of the contents of the cells forming these 

 vessels, in which nuclei are concealed ; e, Cfpcal terminations of the vessels ; /, one of these 

 terminations, still pretty distinctly recognizable as a formative cell ; g, isolated formative cells 

 about to join with the actual vessels. 



