/. - l&ttt. 



brought oul lly in a study of the lymphatic system in rept 



\ •• r a confused account of the origin of tin- anterior lym 

 hearts he describes the development of the peripheral lymph vessels 

 out of tissi - He says that whereas in mammals the greater 



Dumber of the lymphatic vessels come fr extra-intimal spaces (57, 



p. :'~r! ) in reptiles, on the other hand, the lymphatics come from 



- w lllhil: 11 tO the Mill-. 



theory that in the pathway of developing lymphatic < — La 

 certain tissue spaces enlarge ami are added onto the growing tips 

 been worked mil by two pupils of McClure, Kampmeier (66a) an.! 

 Stromsen (146a), both of whom published their work in 1912. 

 Kampmeier's first article (66) is a preliminary report of the second 

 6a i. II*' has worked on the development of the thoracic duct in the 

 pig and bases most of his conclusions on a reconstruction of a speci- 

 men of mine. Kampmeier thinks that the thoracic duct develops in 

 an anterior-posterior direction bj the addition of certain connective 

 i -lie spaces which enlarge in the pathway of a developing vessel. 

 This is a return to the dew of the earlier embryologists, except that 

 >. believed that the growth was from the periphery toward lie center. 

 To a certain extent Kampmeier still holds to the theory of lym- 

 phatics from extra-intimal spaces; that i-. he believes that a part of 

 thoracic duct follow- veins that are degenerating. A vein which 

 lies in the pathway of a developing lymphatic vessel he call- a " veno- 

 lymphatic." This is a different use of the term from that of Hunting- 

 ton and McClure, who used the term to mean a vein which was trans- 

 formed into a lymphatic vessi I. This latter use of the term can well 

 giveD up. since veins do not become lymphatics. The replacing 

 of degenerating veins Kampmeier doe- not regard as a fundamental 

 process in the development of lymphatics, since they may or may not 

 follow -mh \ein-. Hi thinks that in the development of the thoracic 

 duct about half the duct .ohm- from extra-intimal spaces (66a, p. 

 134). It i- interesting to note in connection with the degeneration 

 of \ein> in Kampmeier's work that he -peak- of the plexus of veins 

 medial to the oervous sympatheticus, fig. 11 (or fig. II in 66a), as 

 veno-lymphatics ; that i-. a- veins which disappear a- the thoracic 

 duct form-, and yet this same plexus of veins can he readily injected 



in embryo pigs '.'". to oil mm. long in which the thoracic dl 



mII formed. It is true that the blood vessels may not -how in 

 uninfected specimens, just as the plexus of blood capillaries around 



