STRUCTURE OF LYMPHATIC GLANDS. 207 



Kolliker's view is generally adopted, that the lymphatic 

 glands interrupt the current of the lymph, the afferent 

 vessel resolving itself into the parenchyma of the gland 

 and reconstituting itself out of it. This condition we 

 cannot well compare with anything else than a kind of 

 filtering apparatus, something like our ordinary sand or 

 charcoal filters. 



When a gland is cut across, a structure is frequently 

 brought to view resembling that of a kidney. At those 

 points where the afferent vessels break up, a firmer sub- 

 stance is seen to lie, half surrounded by which a kind of 

 hilus marks the spot at which the lymphatic vessels again 

 forsake the gland. Here there is found a reticular tissue 

 with an often distinctly areolar or cavernous structure, 

 into which, besides the efferent lymphatic vessels, blood- 

 vessels also enter on their way into the proper substance 

 of the gland. Kolliker has accordingly distinguished a 

 cortical and a medullary substance but the so-called 

 medullary substance scarcely retains the character of 

 glandular tissue. This is found chiefly in the cortical 

 substance, which is of greater or less thickness, and it is 

 therefore best to call the medullary substance simply the 

 hilus, since afferent and efferent vessels lie there in close 

 contact, just as in the hilus of the kidneys the ureters and 

 veins emerge, whilst the arteries enter. The essential 

 part of the gland is therefore the periphery, the often 

 kidney-like cortical substance. 



In this can be distinguished, whenever the gland is at 

 all well developed (and in some cases of pathological en- 

 largement it is extremely distinct) even with the naked 

 eye, little, roundish, white or grey granules lying side 

 by side. When the part is moderately well filled with 

 blood, around each granule may be pretty nearly 

 always discerned a red circle of vessels. These granules 

 have long been called follicles, but it was doubtful 



