204 SPECIAL HISTOLOGY. 



distinguished from those of the cortical substance by their less 

 number and the elongated figure of the meshes of the plexus 

 which they form, although at the boundary of the pyramids 

 the two sets are continuous with each other. The renal veins 

 commence in two situations, viz. at the surface of the organ 

 and at the apices of the papillae. In that situation, minute 

 venous radicles collect together from the outermost portions of 

 the capillary plexus of the cortical substance, which either 

 regularly surround each cortical lobule, and between them 

 unite in a stellate manner (stellulae Verheynii) into somewhat 

 larger roots, or, extending over several or numerous lobules, 

 collect into larger trunks. These two sets of veins, forming 

 the vena interlobular es, then penetrate more deeply in com- 

 pany with the arteries of the same name, between the cortical 

 fasciculi, where they are enlarged by the accession of nume- 

 rous other venous radicles from the interior of the cortical 

 substance, and proceed to join the larger veins, either directly 

 or united into somewhat larger trunks, and for the most part 

 at right angles. These lie, together with the larger arteries, 

 around the periphery of the pyramids, ultimately opening into 

 large veins without valves, as are all the renal veins, and which 

 lying singly close to the arteries, quit the kidney in the same 

 way. Previously to this, however, besides those of the 

 column® Bertini, they receive the veins of the pyramids, which 

 commence in a beautiful plexus surrounding the orifices of the 

 tubuli uriniferi on the papilla, and ascend between the tubuli 

 recti, being strengthened by additional radicles; these united 

 with the arteries of the pyramids, the vasa efferentia of the inner- 

 most glomeruli or the arteriole recta, into larger vascular bundles, 

 lying between the " pyramids of Ferrein," open into the arched, 

 wider, venous ramification which encompasses the pyramids. 



The vessels of the membranes of the kidney, arise in part from 

 the art. renalis, before it enters the hilus, and from the supra- 

 renal and lumbar arteries, in part, also, they are branches of 

 the arterice interlobular es, which, after supplying the Malpighian 

 bodies, send on fine twigs to the fibrous coat, forming in it a 

 wide-meshed capillary plexus, which is also continuous with 

 that of the capsula adiposa. 



The kidneys present, proportionally, but few lymphatics. They 

 run, in the interior, along the larger vessels, and do not appear 



