STEUCTUEE OF LYMPHATIC GLAXDS. 



19C 



Fi?. 129. 



Fix. 129. 



Mesenteric 



Section v 

 Gland from the Ox, slightly jiagni- 



FIED. 



a, hilus ; h, medullary sub.stance ; c, 

 cortical substance with indistinct alveoli ; 

 d, cajisule (after KoUiker). 



lowing account is founded cliiefly on the descriptions of His and 

 Kcilliker. 



A lymphatic gland is covered externally with a coat (fig. 128^ c, 

 129, d) composed of connective 

 tissue, mixed in certain animals, 

 with muscular fibre-cells. This 

 coat or capsule is complete, except 

 at the part where it gives passage 

 to the efferent lymphatics and the 

 larger blood-vessels ; and this part 

 of the gland, which often presents 

 a depression or fissure, may be 

 named the hilus (fig. 128, 129 a). 

 The proper substance of the gland 

 consists of two parts, the corti- 

 cal (c), and within this the medul- 

 lary. The cortical part occupies all 

 the superficial part of the gland, 

 except the hilus, and in the larger 

 glands may attain a thickness of 

 from two to three lines. The medul- 

 lary portion occupies the centre, 

 and extends to the surface at the hilus. It is best marked in the 

 inwardly-seated glands, such as the lumbar and mesenteric, whilst in 

 the subcutaneous glands it is more or less encroached upon by a core 

 of connective tissue (hihis-sfroma, His), which enters with the larger 

 blood-vessels at the hilus, and surrounds them, together with the lymph- 

 vessels, in the centre of the gland, so that 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. The trabeculas pass inwards from the capsule 

 (fig. 128). They consist, in the ox, 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 

 divide the space into small compartments, alveoli, from J^j to 2^^ of an 

 inch wide, which communicate laterally with each other through openings 

 in the imperfect partitions betv/een them (fig. 130 a). On reaching 

 the medullary part the trabeculaj take the form of flattened bands or 

 cords, and by their conjunction and reticulation form a freely intercom- 

 municating meshwork throughout the interior. (In the figures they are 

 represented mostly as cut across.) In these alveoles and meshes is 

 included the proper glandular substance, which appears as a tolerably 

 firm pulp or parenchyma, agreeing in nature with lymphoid tissue. In 

 the alveoli of the cortical part this forms rounded nodules (fig. 128 C, 

 130 A cJ) ; in the trabecular meshes of the medullary part it takes the 

 shape of rounded cords {lymplioid cords) joining in a corresponding 

 network (figs. 128, M; 130, b, d) -, and, as the containing meshes 

 communicate, so the contained gland-pulp is continuous throughout. 

 But both in the cortical alveoles and the medullary trabecular meshes, a 

 narrow space, left white in the figs. (128 I, s ; 130, 1, I) is left all round 

 the gland-pulp, between it and the alveolar partitions and trabecular 

 bands, like what would be left had the pulp shrunk away from the 



