DEVELOPMENT AND FUNCTION OF HEMAL NODES 385 



and the germinal centers and follicular cords in all ages are 

 composed of a syncytimn the elements of which (cells, fibers 

 and protoplasm) form a continuous whole. The erythrocytes 

 which are later set free appear in the hyaloplasm of the reticular 

 cells before any gangliaform enlargement is present. The pro- 

 duction of erythrocytes does not cease in embryonic hfe, how- 

 ever, but may continue in adult life from the nuclei of lympho- 

 cytes. A full statement of Retterer's conclusions will be found 

 in the original and in earlier articles. 



von Schumacher '12b regards all hemolymph nodes as 'rudi- 

 mentary forms' of lymph nodes and holds that the former 

 always arise from the latter by a degeneration of the afferent 

 and efferent lymphatics, either without or within the node. If 

 the blood cells within the sinuses are subsequently destroyed 

 then the hemolymph node is converted into an ''ordinary white 

 lymph gland without lymphatics." von Schumacher also thinks 

 it probable that the latter nodes may as a result of sprouting 

 of the obliterated vessels again become a true lymph node. It 

 is of special interest that although von Schumacher holds that 

 lymph nodes may develop wholly independently of lymph vessels 

 he nevertheless claims that hemal nodes are not organs sui 

 generis. 



Rabl '13^ found both vascular and lymphatic connections 

 in the developing hemolymph glands (Blutlymphdriisen) of 

 the guinea pig and claimed that the peripheral sinus of hemo- 

 lymph nodes contains blood from the beginning. It should 

 be noted especially, however, that in the cervical node described 

 and reconstructed by Rabl and regarded by him as a lymph 

 node the sinus was formed from the jugular lymph sac and two 

 veins which still communicated with the jugular vein. Hence 

 Rabl regards the sinus as a remnant of the original communi- 

 cation of the node with the vein, which still carries blood to 

 the sinus of the nodes. Nevertheless Rabl emphasizes that 

 the only difference between his con,ception of the development 

 and that of Sabin is that he regards the origin,al vessel which 



* As reported in Studies on hemal nodes 111, Anat. Anz. Bd. 45, 1913, 1 have 

 never found a hemal node in the guinea pig. 



