384 



LYMPHATIC SYSTEM. 



upon by the connective tissue which enters with the larger blood-vessels at the hilum, 

 and surrounds them, together with the lymph-vessels, in the centre of the gland, 

 so that in these the medullary part is reduced to a layer of no great thickness 

 bounding inwardly the cortical part. 



Throughout both its cortical and medullary part the gland is pervaded by a 

 trabecular frame-work which incloses and supports the proper glandular substance. 



Fig. 442. SECTION OF A MESENTERIC GLAND OF THE ox (MAGNIFIED 12 DIAMETERS). After His. 



The section includes a portion of the cortical part, A, in its whole depth, and a smaller portion of 

 the adjoining medullary part, B ; c, c, outer coat or capsule sending partitions into the cortical part, 

 eventually forming the trabeculse. t, t, which are seen mostly cut across ; d, d, the glandular substance 

 forming nodules in the cortical part, A, and reticulating cords in the medullary part, B ; I, I, lymph- 

 sinus or lymph-channel, left white. 



The trabecuhe pass inwards from the capsule (fig. 440). They consist, in the ox 

 and most animals, chiefly of plain muscular tissue ; in man, of connective tissue, 

 sparingly intermixed with muscular fibre-cells. In the cortical part they are mostly 

 lamellar in form, and partially divide the cortex up into separate nodules from ^ 

 to Y V of an inch in diameter, which communicate laterally with each other through 

 openings in the imperfect partitions between them (fig. 442, A). On reaching the 

 medullary part the trabeculse take the form of flattened bands or rounded cords, 

 and by their conjunction and reticulation form a freely intercommunicating mesh- 

 work throughout the interior. (In figure 442 they are represented mostly as cut 

 across.) In the interstices of the framework which is thus formed by the capsule 

 and trabeculae is included the proper glandular substance, which appears as a 

 tolerably firm pulp or parenchyma, composed of lymphoid tissue. Within the 

 cortical part this forms rounded nodules (cortical nodules or follicles) (fig. 442, A, d} ; 

 in the trabecular meshes of the medullary part it takes the shape of rounded cords 

 (lymphoid cords') joining in a corresponding network (fig. 442, B) ; and, as the 

 containing meshes of the framework inter-communicate, so the contained gland- 

 pulp is continuous throughout. But both in the cortical and the medullary parts, 

 a narrow space, left white in the figs. (fig. 440, Ls ; 442, I, /), is left all round the 

 gland-pulp, between it and the trabeculse, such as would be left had the pulp shrunk 

 away from the inside of a mould in which it had been cast. This space is both a 

 receptacle and a channel of passage for the lymph that goes through the gland ; it 

 is named the lymph-sinus, or lymph-channel. It is traversed by retiform connective 



