GIL XXITI.] 



LYMPHATIC GLANDS 



317 



the mesentery, and along the great vessels of the abdomen, thorax, 

 and neck ; in the axilla and groin ; a few in the popliteal space, but 

 not further down the leg, and in the arm as far down as the elbow. 



A lymphatic gland is covered externally by a capsule of con- 

 nective tissue, generally containing some unstriped muscle. At the 

 inner side of the gland, which is somewhat concave (hilus), the 

 capsule sends inwards processes called trabeculce in which the blood- 

 vessels are contained, and these join with other processes prolonged 

 from the inner surface of the 

 part of the capsule covering the 



convex or outer part of the j I 



gland ; they have a structure ~MHSml \ 



similar to that of the capsule, 

 and entering the gland from all 

 sides, and freely communicating, 

 form a fibrous scaffold ing. The 

 interior of the gland is seen on 

 section, even when examined 

 with the naked eye, to be made 

 up of two parts, an outer or 

 cortical, which is light coloured, 

 and an inner or medullary por- 

 tion of redder appearance (fig. 

 273). In the outer part, or 

 cortex, of the gland the intervals 

 between the trabeculse are large 

 and regular; they are termed 

 alveoli ; whilst in the more 

 central or medullary part is a 

 finer meshwork formed by an 

 irregular anastomosis of the tra- 

 becular processes. Within the 

 alveoli of the cortex and in the 

 meshwork formed by the trabec- 

 ulaa in the medulla, is contained 



FIG. 274. A small portion of medullary substance 

 from a mesenteric gland of the ox. d, d, Trabe- 

 culae ; a, part of a cord of lymphoid tissue from 

 which all but a few of the lymph-corpuscles 

 have been washed out to show its supporting 

 meshwork of retiform tissue and its capillary 

 blood-vessels (which have been injected, and 

 are dark in the figure); b, b, lymph-path, of 

 which the retiform tissue is represented only 

 at c, c. x 300. (Kolliker.) 



lymphoid tissue ; this occupies 



the central part of each alveolus ; but at the periphery, surrounding 

 the central portion and immediately next the capsule and trabeculse, is 

 a more open meshwork of retiform tissue constituting the lymph-path, 

 and containing but few lymph-corpuscles. At the inner part of the 

 alveolus, the 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 than in the cortex ; spaces (fig. 274 b), 

 are left within those anastomosing cords, in which are found portions 

 of the trabecular meshwork and the continuation of the lymph-path. 



