LYMPHATIC GLANDS. 



305 





relation with it, a communication must exist, and this is obtained by the numerous spaces in the 

 follicle itself, so that a lymph-follicle is a true lymphatic apparatus whose juices and lymph- 

 corpuscles can pass into the nearest lymphatic. The follicles are surrounded by a network of 

 blood-vessels which sends loops of capillaries into their interior (fig. 220, B). We may assume 

 that lymph-corpuscles pass from these capillaries into the follicle. 



In connection with these follicles, including those of the back of the tongue, the solitary 

 glands of the intestine and the adenoid tissue in the bronchial tract, the tonsils, and Peyer's 

 patches, it is important to remember that enormous numbers of leucocytes pass out between 

 the epithelial cells covering these follicles. The extruded leucocytes undergo disintegration 

 subsequently. 



(2) The compound lymph-glandsthe lymphatic glands represent a collection of lymph- 

 follicles, whose form is somewhat altered. Every lymph-gland is covered externally with a 

 connective-tissue capsule (fig. 221, c), which contains numerous non-striped muscular fibres. 

 From its inner surface, numerous 

 septa and trabecule (r.)pass into the 

 interior, so that the gland-substance 

 is divided into a large number of 

 compartments. These compartments 

 in the cortical portion of the gland 

 have a somewhat rounded form, and 

 constitute the alveoli, while in the 

 medullary portion they have a more 

 elongated and irregular form. [On 

 making a section of a lymph-gland 

 we can readily distinguish the cor- 

 tical from the medullary portion of 

 the gland.] All the compartments 

 are of equal dignity, and they all 

 communicate with each other by 

 means of openings, so that the septa 

 bound a rich network of spaces 

 within the gland, which communi- 

 cate on all sides with each other. 



These spaces are traversed by the 

 follicular threads (fig. 222, /, /). 

 These represent the contents of the 

 spaces, but are smaller than the 

 spaces in which they lie, and do not Diagrammatic section of a lymphatic gland, a.l., afferent, 

 come into contact anywhere with e.l., efferent, lymphatics ; C, cortical substance ; M, 

 the walls of the spaces. If we reticular cords of medulla ; l.s, lymph-sinus ; c, capsule, 

 imagine the spaces to be injected with trabecular, tr. 

 with a mass, which ultimately 



shrinks to one-half of its original volume, we obtain a conception of the relation of these 

 follicular threads to the spaces of the gland. The blood-vessels of the gland (b) lie within 

 these follicular threads. They are surrounded by a tolerably thick crust of adenoid tissue, 

 with very fine meshes (x, x) filled with lymph-corpuscles, and with its surface (0, 0) covered by 



ch 

 the narrow meshes. 



Between the surface of the follicular threads and the inner wall of all the spaces of the 

 gland, lies the lymph-channel or lymph-path (B, B), which is traversed by a reticulum of 

 adenoid tissue, containing relatively few lymph-corpuscles. It is very probable that these 

 lymph-paths are lined by endothelium. 



The vasa afferentia (fig. 221, a.l.), of which there are usually several, expand upon the 

 surface of the gland, perforate the outer capsule, and pour their contents into the lymph-paths 

 of the gland (C). The vasa efferentia, which are less numerous than the afferentia, and come 

 out at the hilum, form large, wide, almost cavernous dilatations, and they anastomose near 

 the gland (e.l.). Through them the lymph passes out at the opposite surface of the gland. 

 The lymph percolates through the gland, and passes along the lymph-paths, which represent 

 a kind of rete mirabile interposed between the afferent and efferent lymph-vessels. 



During its passage through this complicated branched system of spaces, the movement of 

 the lymph through the gland is retarded, and, owing to the numerous resistances which occur 

 in its path, it has very little propulsive energy. The lymph-corpuscles which lie in the 

 meshes of the adenoid reticulum are washed out of the gland by the lymph-stream. The 

 lymph-corpuscles lying within the follicular threads pass through the narrow meshes (0) into 

 the lymph-paths. The formation of lymph-corpuscles either occurs locally, from division of 

 the pre-existing cells, or new leucocytes wander out into the follicular threads. The movement 

 of the lymph through the gland is favoured by the muscular action of the capsule. When the 



TJ 



the cells of the adenoid reticulum, in such a way as to leave free communications through 



