DEVELOPMENT AND FUNCTION OF HEMAL NODES 



395 



the node. The i:)eripheral blood space is decidedly irregular 

 possessing invaginations into the body of the node and evagina- 

 tions into the surrounding mesenchyme which in sections not 

 infrequently give the impression of being sections of vessels. 

 Few cell outlines are distinctly visible and many of the nuclei ap- 

 pear more like those of older lymphocytes. Some erythrocytes 

 are scattered throughout the node but no intra-nodal sinuses 

 are present. Many of the cells represent a more primitive type 



Fig. 12 Arteriole penetrating interior of same node without communicating 

 with the subcapsular blood space. X 475. 



however. No lymphatics whatever could be recognized near 

 this node. 



A still older stage in the development of hemal nodes is shown 

 in figure 13. In this specimen the capsule still grades directly 

 over into the surrounding connective tissue but the increase 

 in erythrocytes is very marked, especially within the parenchyma 

 of the nodes where they mingle far more freely with the lympho- 

 cytes than the drawing shows. Large>r arterioles are present 



