158 



HISTOLOGY. 



leaves in the efferent vessels, fewer in number than the afferent. Lympho- 

 cytes are added to the lymph as it passes across the gland. 



Nerves to the lymph glands are not abundant. They consist of medul- 

 lated and non-medullated fibers which form plexuses about the blood 

 vessels, and supply the muscle cells in the capsule and trabeculae. They 

 have not been found in the nodules and cords. 



Sinus. 



Capsule 



Trabeculae. 



Cortical 

 substance. 



Germinal 



center of a 



secondary 



nodule. 



FIG. 179. LONGITUDINAL SECTION OP A HUMAN CERVICAL LYMPH GLAND. X is. 



The function of the lymph glands is not only to produce lymphocytes 

 which enter the lymphatic vessels, but also to "filter the lymph." If cer- 

 tain poisonous substances, inert particles, or bacteria are brought to the 

 gland in the lymph, they may be removed by phagocytic endothelial or 

 reticular cells. The gland at the same time may become enlarged by con- 

 gestion, and by multiplication of its cells. 



