1 1 /.'. Sabin. 



the lymphatics and the fact thai they aever join with the con- 



- 

 Tin - rvation of the growth of capillaries by sprouting 



iver and over again where there was the chance oi - ■ ■ ! u ur 

 the 3s in ag form or of obtaining injected specimens, 



and yet during all these years the observations were Dot generally 

 ted, since as the fundamental morphology of the Lymphat 

 : was unknown, tin- significance of the observations c-< m 1«1 not be 

 understood. 



It is. however, oot true that everj who studied the living 



- .Hi described the process of the sprouting of the endothelial 

 wall of hi.- - .Mill of lymphatics a- showing the method of 



growth. Indeed at leas! 31 rve*rs have doubted whether iliere 



tun different kinds of capillaries in the tadpole's tail. I have 

 already noted that Strieker doubted the presi dee "f lymphatic capil- 

 laries in the tadpole's tail. 



Wysotzky (155), whose work, since it is published in Russian, 

 1 quote from Mayer (89), thought that the capillaries without blood 

 merely young blood capillaries. 

 S _ ■■■:■■ Via er (89), in an interesting and valuable paper, " I 

 die Bh gefasse im Schwanze der Batrachierlarven," gives first 



an excellent analysis of the literature on the subject of the capillaries 

 in the tadpole's tail. Be brings out the fact that it was the presence 

 of an occasional red corpuscle in the "lymphatic" which was the 

 stumbling block in accepting the presence of lymphatic capillaries. 

 !|. then records an observation which in reality cleared up the entire 

 difficulty in regard to the "empty capillaries." \- E. Et. Clark (26) 

 - shown. Mayer, however, failed to see the bearing of his own 

 servations. Slayer used curare and the electric current to anaes- 

 thetize the larva and then covered the tail with a cover slip. When he 

 ked the water out from under the cover slip he noted that the 

 iod would gradually stop flowing or even go in the reverse direction 

 in the blood capillaries and that the vessel would collapse, so that 



ked like ,1 solid cord. Thus he also observed the contraction of 

 endothelium. Furthermore, he noted that the "other empty vessels" 

 (namely, lymphatics), contracted more frequently than the blood 

 capillaries. When, however, he studied these other empty vessels lie 

 thought that thi onal cells in them flowed now toward tin center, 



now toward, the periphery, and he ended with the somewhat vag 



