TISSUES OF THE BODY. 



375 



Fig. 373. Vertical section through the mucous mem- 

 brane of the conjunctiva of the ox, from the lower 

 lid. a, large lymphatic vessel ; b, follicle ; c, super- 

 ficial lymphatic canals. 



d 



207. 



That difficulty of filling the peripheral portions of lymphatics owing to 

 their valves, already mentioned in the preceding section, we have recently 

 learned to overcome. The fol- 

 lowing is the method usually 

 employed, known as Hijrtl's 

 method of puncture : A fine 

 cannula is passed into such parts 

 as are supposed to contain lym- 

 phatics, and through this the 

 injection fluid is gently forced. 

 The extensive researches of 

 Teichmann have greatly in- 

 creased our knowledge as re- 

 gards this branch of study, be- 

 side which other contributions 

 have been made by Ludioig and 

 his pupils, Tomsa, Zawaryltin, 

 and MacGillavry, as well as by His, Frey, Langer. 



As far as is known at present, the radicals of absorbents, the peripheral 

 lymphatic canals, occupy the in- 

 terstitial connective-tissue of the 

 various organs, or are at least 

 always situated in its course. 



They are seen here either in 

 the form of networks, reminding 

 us of the peripheral portions of 

 the circulation, or they begin in 

 blind passages which are sub- 

 sequently united in a reticular 

 manner. 



The first form is met with, in 

 general, where the surface of an 

 organ is smooth, or in the in- 

 terior of the latter (figs. 373, 

 374, 375, 377) ; the second in 

 parts of the body where the sur- 

 face is covered by round or 

 tufted appendages (figs. 371, 

 376). 



The arrangement of the canals, however, in the various regions of the 

 body is variable enough, and we miss everywhere that beautiful regularity 

 to be seen among the capillaries of the blood-vessels. 



The diameter of lymphatic canals is in general much more considerable 

 than that, of the capillaries, ranging from 0'0113 to 0-0451. Only for 

 short distances, however, do they preserve anything like the same diameter 

 of lumen. As a rule, these vessels present strong dilatations and sudden 

 constrictions, down to about 0'0027 mm. and less ; and so on. The 

 whole may present frequently a jagged or knotted appearance, diffi- 

 cult of description (fig. 373, 374), but which to a practised eye is unmis- 

 takable. 



The amount of lymphatic vessels varies in the different organs, and 

 25 



Fig. 374. Prom the thyroid gland of the Infant, a, c, 

 glandular spaces ; d, /, larger and terminal lym- 

 phatics. 



