ABSOEPTIOX BY LYMPHATICS. 



365 



the tissues in which they lie ; and changes in the cha- 

 racter of the lymph correspond very closely with changes 

 in the character of either the whole mass of blood, or of 

 that in the vessels of the part from which the lymph is 

 examined. Thus Herbst found that the coagulability of 

 the lymph is directly proportionate to that of the blood ; 

 and that when fluids are injected into the blood-vessels 

 in sufficient quantity to distend them, the injected sub- 

 stance may be almost directly afterwards found in the 

 lymphatics. 



It is not improbable, however, that some other matters 

 than those originally contained in the exuded liquor san- 

 guinis may find their way with it into the lymphatic 

 vessels. Parts which having entered into the composition 

 of a tissue, and, having fulfilled their purpose, require to 

 be removed, may not be altogether excrementitious, but 

 may admit of being re-organised and adapted again for 

 nutrition ; and these may be absorbed by the lymphatics, 

 and elaborated with the other contents of the lymph in 

 passing through the glands. 



Lymph-Hearts. In reptiles and some birds, an important 

 auxiliary to the movement of the lymph and chyle is sup- 

 plied in certain muscular sacs, named lympli-liearts (fig. IOO), 

 and Mr. Wharton Jones has lately shown that the caudal 

 heart of the eel is a lymph-heart also. The number and 

 position of these organs vary. In frogs and toads there 

 are usually four, two anterior and two posterior ; in the 

 frog, the posterior lymph-heart on each side is situated in 

 tlie ischiatic region, just beneath the skin ; the anterior 

 lies deeper, just over the transverse process of the third 

 vertebra. Into each of these cavities several lymphatics 

 open, the orifices of the vessels being guarded by valves, 

 which prevent the retrograde passage of the lymph. From 

 each heart a single vein proceeds and conveys the lymph 

 directly into the venous system. In the frog, the inferior 

 lymphatic heart, on each side, pours its lymph into a 



