THE LYMPH-NODES. 



in 



vessels. Although both the afferent and efferent lymphatics are provided 

 with valves close to the node, no such folds occur along the sinuses. The 



Trabecula 



Lymph-sinus 



FTG. 150. Portion of medulla of lymph-node, showing details of lymph-sinus and medullary 



cords. X 250. 



passage of the lymph through the node is retarded by the reticulum within 

 the sinuses, thus favoring the entrance of the young lymphocytes from the 



FIG. 151. Cross-section of small lymph-node, injected to show rich vascular supply. X 10. 



bordering lymphoid tissue into the sluggishly moving lymph-stream. Germ- 

 centres, the particular foci for the production of lymphocytes, usually are 

 present within the cortical nodules, but are not found in the medullary cords. 



