THE ORIGIN AND EARLY DEVELOPMENT OF THE 

 POSTERIOR LYMPH HEART IN THE CHICK 



RANDOLPH WEST 



Frotn the Laboratories of Comparative A natomy, Princeton and Columbia 



Universities 



FOURTEEN FIGURES 



INTRODUCTION 



During the autumn of 1912 Professor McClure suggested 

 to the writer the advisability of working out the early develop- 

 ment of the posterior lymph heart in the chick, with especial 

 reference to the source of its endotheUum. Throughout the 

 following winter the problem was carried on under Professor 

 McClure's supervision at Princeton University, while during 

 the past year it has been continued under the direction of Pro- 

 fessor Huntington at Columbia University. 



Sala (1) in 1900 described the development of the posterior 

 lymph heart of the bird, and gave a review of the literature to 

 that date. In the caudal sections of an embryo of six days and 

 eighteen hours incubation he finds that: 



In the mesencliyme which stands in the lateral relation to the caudal 

 myotomes and corresponds to the lateral branches of the first five 

 coccygeal veins, a progressive excavation occurs of little spaces or 

 fissures which soon enter into communication with the lateral venous 

 branches themselves — one would say in fact that these fiSsures are 

 onl}^ simple dilatations and ramifications of the veins themselves. 



If the writer interprets him correctly, Sala states that the l3'mph 

 hearts are formed b}^ an addition of spaces to the veins, and then 

 a few lines later intimates that these spaces might be considered 

 as ''ramifications of the veins themselves." He also states that 

 the 'fissures' are at first few in number and are arranged in a 

 linear series, parallel to the axis of the vertebral column, corre- 



403 



THE AMERICAN JOURNAL OF ANATOMY, VOL. 17, NO. 4 

 MAY. 191.5 



