5IO VESSELS OF LYMPHATIC GLANDS. [SECT. 2l8. 



gradually wider and wider in their course towards the centre, 

 and towards the hilus of the gland. Here they unite with 

 each other by degrees to form the wide vas lymphaticum ef- 

 ferens, which is either single or multiple. This vessel, accord- 

 ingly, is not related to the glandular parenchyma at all in the 

 same way as the vasa afferentia, as has hitherto been universally 

 assumed ; indeed it has nothing to do with the cortical substance, 

 and in all the larger glands with a well-formed hilus, it passes 

 directly from the hilus without ever coming in contact with the 

 cortical substance. The course of the chyle-vessels in a lymphatic 

 gland is, therefore, the following : The vasa efferentia pass from 

 many peripheral points to the convex side of the gland, and, 

 entering the cortical substance, pass into the lacunar system of the 

 alveoli, the spaces of which are to be regarded as the continuation 

 of the vessels. Thence, provided anew with walls, the lymphatics 

 pass into the medullary substance, and here produce a rich plexus, 

 from which, lastly, one or more vasa efferentia emerge, and leave 

 the gland directly through the hilus. — With regard to the structure 

 and width of the vessels of the medullary substance, it is still to 

 be remarked, that they all possess an epithelium of elongated 

 cells, a distinct tunica intima, consisting of connective tissue with 

 interspersed nuclei (plasmatic cells?). The tunica media of the 

 lymphatics is here composed of smooth muscular fibres, which are 

 easily recognised, and appear to have an exclusively transverse 

 direction : the tunica adventitia is replaced by the connective 

 tissue, which forms the stroma of the medullary substance. In 

 microscopical sections, these vessels are very easily distinguished 

 from the arteries of the medulla by the absence of the elastic 

 inner coat, and the slighter development of the muscular fibres ; 

 while the veins, even down to the fine twigs, are characterised by 

 an abundant intermixture of fine elastic fibrils, which are totally 

 absent even in the large lymphatic vessels of the medulla. — The 

 width of the lymphatics of the medulla varies from 1 S '" to ^'" ; 

 close at the origin of the vasa efferentia they measure only //", 

 ^V", or even J/", and this small diameter is maintained as the 

 vessels approach the cortex. 



The arteries of the lymphatic glands are mostly multiple. The 

 largest always passes through the hilus into the interior of the 

 gland, and is frequently joined by others which run to the medulla, 

 either alone or by the side of small vasa efferentia, which leave the 

 gland at other depressed spots resembling hiluses. In the medulla, 

 a coarser ramification of these vessels is formed by all the main 

 branches of them proceeding to the several parts of the cortex, 



