VESSELS. ARTERIES. VEINS. CAPILLARIES, ETC. 9 



central medullary portion, and with the terminal 

 branches of the afferent lymphatics ; they contain an 

 alkaline liquid, and organized corpuscles, amongst 

 which we can distinguish little cells, averaging ai^th 

 of a line in diameter, and spherical granular nuclei of 

 from 4^oth to ^oth of a line. These elements are 

 identical with those which exist in lymph and chyle. 



The medullary substance, striated in appearance, is 

 enveloped on all sides of the cortical substance, except 

 at those points where the afferent vessels enter the 

 gland. It is made up, mainly, of the terminal radi- 

 cles of the afferent vessels, which, taking their origin 

 in the deeper cavities of the cortical substance, anas- 

 tomose with each other and form a network, whose 

 branches, becoming gradually larger in size, and 

 fewer in number, finally terminate in one or two 

 efferent lymphatic vessels, which make their exit at 

 the hilus of the gland. 



The arteries, most of which terminate in the cor- 

 tical substance, either arrive there directly, or after 

 traversing the medullary portion of the organ, to 

 which they give off a few branches. In the trabeculse 

 of the cortical substance these vessels form an intri- 

 cate capillary plexus, which is directly in contact 

 with the cells of the gland. 



The veins, fewer in number and greater in volume 

 than the arteries, accompany them in their course. 

 The nerves are not numerous ; they enter the gland 

 with its vessels, and their mode of termination is 

 unknown. 



The structure of a lymphatic gland may be summed 

 ( up as follows: the essential or secreting portion of 





