ABSORPTION. 



307 



mediately next the capsule and trabeculae, is a more open mesh work of 

 adenoid tissue constituting the lymph sinus or channel, and containing 

 fewer lymph corpuscles. The central mass is inclosed in endothelium. 

 the cells of which join by their processes, the processes of the adenoid 

 framework of the lymph sinus. The trabeculas are also covered with 

 endothelium. The lining of the central mass does not prevent the pas- 

 sage of fluids and even of corpuscles into the lymph sinus. The frame- 

 work of the adenoid tissue of the lymph sinus is nucleated, that of the 

 central mass is non-nucleated. At the inner part of the alveolus, the 

 wedge-shaped central mass divides into two or more smaller rounded or 

 cord-like masses which joining with those from the other alveoli, form a 

 much closer arrangement of the gland tissue than in the cortex; spaces 



FIG. 224. A small portion of medullary substance from a mesenteric gland of the ox. d, d, 

 trabeculae; a, part of a cord of glandular substances from which all but a few of the lymph-corpus- 

 cles have been washed out to show its supporting meshwork of retif orm tissue and its capillary 

 blood-vessels c which have been injected, and are dark in the figure) ; 6, 6, lymph-sinus, of which 

 the retiform tissue is represented only at c, c. X 300. (Kolliker.) 



(Fig. 223 #), are left within those anastomosing cords, in which are 

 found portions of the trabecular meshwork and the continuation of the 

 lymph sinus. 



The essential structure of lymphatic-gland substance resembles that 

 which was described as existing, in a simple form, in the interior of the 

 solitary and agminated intestinal follicles. 



The lymph enters the gland by several afferent vessels, which open 

 beneath the capsule into the lymph-channel or lymph-path; at the same 

 time they lay aside all their coats except the endothelial lining, which 

 is continuous with the lining of the lymph-path. The efferent vessels 



