632 



THE LYMPHATICS. 



LYMPHATIC GLANDS. 



The lymphatic glands are ovoid, spherical, or discoid bodies of medium 

 consistency, grey, rosy, or red-coloured, and sometimes quite black, and 

 which at several points intercept the course of the lymphatic vessels. 



Their number is considerable, and they are rarely isolated; most 

 frequently they are collected .in groups along the blood-vessels. They are 

 always larger in youth than in old age. 



All the canals of the lymphatic system are provided with at least one 

 gland on their course, and some even traverse two or three before opening into 

 the thoracic duct or great lymphatic vein. On reaching these glands, they 

 plunge into their structure in ramifications, appearing on the opposite point 

 after being reconstituted into several principal canals, which are generally 

 larger and less numerous than the primitive vessels. The latter take the 

 name of afferents (vasa infer entia or afferentia) ; the others are named 

 efferents (vasa efferentia), because they leave the gland to reach the central 

 canal. 



STRUCTURE. The structure of the glands is extremely complicated, and 

 difficult to make out, in consequence of the delicateness of their tissue. The 

 following is what is positively known in reference to this subject. 



The glands have an envelope of connective tissue (continuous with the 

 tunics of the afferent and efferent vessels), which surrounds a substance that is 

 readily perceived to be composed of two layers of a different aspect : one 

 cortical, the other medullary. 



The first appears to be granular, the second somewhat fibrous. This 

 proper tissue is sustained by connective laminas (or septa continuations of 

 the capsule) which contain smooth muscular fibres. The laminae form alveoli 

 in the cortical layer, and a sort of minute tubes in the central layer. These 

 alveoli are in their turn divided by reticular tissue into secondary spaces, 

 which become smaller as they lie near the centre ; at the periphery, where 



Fig. 296. 



Fig. 297. 



SECTION OF A LYMPHATIC GLAND. 



, a, The fibrous tissue that forms its exterior ; 6, 6, 

 Superficial vasa inferentia ; c, c, Larger alveoli, 

 near the surface; d, d, Smaller alveoli of the 

 interior ; e, e, Fibrous walls of the alveoli. 



SJMPLE LYMPHATIC GLAND. 



a, The capsule with sections of lym- 

 phatics, d, d, passing through it 

 5, Lacunar and intercommunicating 

 passages, permeated by the lymph 

 and forming the superficial lymph 

 path of Frey; c, Nucleus, or me- 

 dullary portion, with section o 

 blood-vessel in the centre. 



they are most voluminous, they are named lymphatic sinuses. Everywhere 

 these sinuses are filled with lymph globules. The arrangement is identical 



