104 THE KIDNEYS, BY C. LUDWIG. 



pass upwards from the papilla itself. These, as they pass 

 throi gh the lacunar spaces or fissures, are speedily joined by 

 others originating from the capillaries of the papillary fasci- 

 culi of urinary tubules, and these again by others proceeding 

 from the capillaries at a somewhat higher level, and so on. 

 From the constant accession the veins thus receive in the 

 direction from the papilla to the cortex, their number becomes 

 gradually increased in the cortical border of a fissure to fifteen 

 or twenty (venulse rectse, fig. 150, vr). 



As the veins surpass the arteries, not only in number, but in 

 size, it comes to pass that the intermediate spaces dividing the 

 fasciculi of urinary tubules from one another in the medulla 

 are chiefly occupied by the former vessels. In the medulla 

 itself the several veins lying contiguous to one another in any 

 fasciculus communicate by frequent looped anastomoses. When 

 the fasciculi have reached the cortex, the different veins they 

 contain quickly coalesce to form several large trunks that enter 

 the large veins of the cortex ; and it usually happens that 

 from each of the fasciculi of urinary tubules bounding a 

 fissural space a venous trunklet arises, which receives the small 

 veins of the adjoining parts ; so that in this way each fasci- 

 culus of veins discharges itself by at least as many trunks 

 into the nearest large vein as there are fasciculi of urinary 

 tubuli around the fissural space. 



In regard to the relation that exists between the blood- 

 vessels and urinary tubules of the medulla, it still remains to 

 be mentioned that the veins ascending in the axis of the 

 fissural space do not come into contact with the collecting 

 tubes, and are the more remote from them the nearer they ap- 

 proximate the surface of the cortex. They behave themselves 

 differently, however, in regard to the limbs of the loops, the 

 descending limb running between the venous fasciculi in the 

 upper parts of the marginal medullary layer, when they pass 

 from the region of tortuous canals to the fasciculi of straight 

 medullary canals. 



VESSELS OF THE FIBROUS CAPSULE. As is usual in such 

 fibrous membranes and fasciae, a wide-meshed capillary plexus 

 is distributed over the surface and in the substance of the 



