STRUCTURE OF LYMPHATIC GLANDS. 439 



XXVIIL STRUCTURE OF THE LYMPHATIC 

 GLANDS. (PLATE V.) 



IT is now generally admitted, that the afferent communicate 

 in the interior of the lymphatic glands with the efferent 

 vessels. These glands, indeed, consist of a dense network of 

 lymphatics, in the meshes of which the arteries, veins, and 

 nerves ramify. Much difference of opinion still exists, how- 

 ever, as to the nature of the communication between the 

 afferent and efferent vessels, and no definite idea is enter- 

 tained regarding the parenchyma of these organs. 



We know that an efferent lymphatic, before it enters a 

 gland, consists of an external tunic of filamentous texture, a 

 middle tunic of fibrous texture, and an internal layer of epi- 

 thelium. 



Immediately after the branches, into which the afferent 

 vessel divides, have penetrated the capsule of the gland, they 

 lose their external tunic. For a short distance, indeed, until 

 they have begun to anastomose with one another, a very thin 

 external tunic, accompanied by a little fat, is still observable. 

 This fat is continuous with the layer of adipose texture which 

 generally exists immediately under the capsule of the gland, 

 and through which the lymphatics must pass to and from the 

 organ. 



The branches of the extra-glandular lymphatics, then, 

 which pass to and from the glands, possess a very thin inter- 

 nal tunic ; but the network of intra-glandular lymphatics 

 which enter into the structure of the gland itself, presents no 



