LYMPHOID TISSUE, LYMPH-NODULES, AND LYMPH-GLANDS. 199 



minated follicles above mentioned. They form a peripheral layer 

 which is, however, not clearly defined in the neighborhood of the 

 hilum. This layer is known as the cortex of the lymph-gland. 

 (Fig. 161.) The lymphoid tissue of the interior of the gland, the 

 medullary substance, is in the shape of cords medullary cords - 

 which are continuous with the lymphoid nodules of the cortical 

 portion. These connect with each other and form a network of 

 lymphoid tissue, in the open spaces of which lie the trabeculae. At 

 their periphery the nodules and medullary cords are bordered by a 

 wide-meshed lymphatic tissue, the lymph-sinus of the gland, parts 

 of which lie (i) between the capsule and the cortical substance, (2) 



Mitosis. 



Germ center. 



Lymph-sinus. 



^SSS^sk"*"*?^ 

 * t *JW*V - *-*^ e * 



Medullary 

 cord. 



Fig. 162. From a human lymph-gland ; X 2 4- At a are seen the concentrically 

 arranged cells of the lymph-nodules. (Fixation with Flemming's fluid.) 



between the nodules of the latter and the trabeculae, (3) between 

 the medullary cords and the trabeculae, and (4) between the medul- 

 lary substance and the capsule at the hilum. At the hilum the 

 loose lymphoid tissue represents a terminal sinus (Toldt). These 

 sinuses are lined throughout by endothelial cells, which are continu- 

 ous with those of the afferent and efferent lymph-vessels. The 

 lymph flows into the gland through the afferent vessels, and passes 

 along into the interior through the spaces offering the least resist- 

 ance (sinuses). The latter represent those peripheral portions of 

 the nodules and of the medullary cords in which the lymphoid tissue 

 is present in Joose arrangement. The lymph consequently envelops 



