LYMPH GLANDS. 



155 



in its meshes, forms a coarser net in the germinative centers than in the 

 peripheral part of the nodule. Blood vessels within the nodule are incon- 

 spicuous and the surrounding lymphatic vessels are sometimes absent. 



Afferent lymphatic vessels. 



ft/ 



\ x 



Peripheral 

 lymph sinus. 



Capsule. 



Lymphoid tissue 



/ Blood vessels. / 



Lymphatic vessel. Lymphatic vessel. 



FIG. 175. 



Afferent lymphatic vessels. 



Peripheral sinus. 



Lymph'sinus. 



Capsule. 



Lymph sinus. 



Medullary cord. 



Trabecula. 



Efferent lymphatic vessels. 



FIG. 176. 

 DIAGRAMS REPRESENTING FOUR STAGES IN THE DEVELOPMENT OF LYMPH GLANDS. 



Certain of the solitary nodules are merely transient local accumulations 

 of lymphocytes which are diffusely distributed in the layer of reticular tissue 

 found beneath the intestinal epithelium. 



