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THE KIDNEYS, BY C. LUDWIG. 



tortuous canal (capsula glomeruli). Taken collectively, there- 

 fore, the arteriae interlobulares give off at least as many 

 branches into the cortex as there are beginnings of urinary 

 tubules in it ; it is very probable also that they do not exceed 

 this number. 



Each of these terminal arterial branches (vas afferens glo- 

 meruli) runs straight from its origin to the nearest terminal 

 dilatation of a urinary tubule. A few of these very numerous 

 vasa afferentia, before they reach the spherical extremity of the 

 urinary tubule, give off a very fine branch, that immediately 

 breaks up into capillaries, through which the blood passes into 

 the capillary plexus investing the urinary tubules. Every vas 

 afferens alike, whether it has previously given off branches, or 

 remained undivided, runs to one of the spherical dilatations of 

 the urinary tubule, and perforates the wall opposite to the 

 commencement of the tortuous canal or neck. On reaching 

 the interior it breaks up into a brush of free capillaries, called 

 the glomerulus, which again within the capsule unite to form a 

 venous trunk, the vas efferens glomeruli. This little vein, of 

 about the same size as the vas afferens, runs in close proximity 

 to the latter, and usually perforates the capsule at the same 

 point. 



Respecting the arrangement of the vessels within the 

 glomerulus, the following facts only are known. The vas 

 afferens divides immediately after its entrance into the spherical 

 capsule into from four to eight branches,which, widely diverging, 

 run towards the neck. In the same manner each branch 

 ramifies, and these secondary twigs coalesce, as it would appear, 

 gradually towards the centre of the capsule to form the vas 

 efferens. Very frequently the capillaries proceeding from the 

 primary branches of the arterial vas afferens reunite into 

 common veinlet, so that the vas efferens is recomposed in the 

 same manner that the afferent trunk divided. When this 

 occurs, the glomerulus presents several vascular lobules, whicl 

 are continuous at either end with an artery and a vein. Al- 

 though the glomerulus is never adherent to the membrane of 

 the capsule, the walls of the capillaries are not in immediai 

 contact with its fluid contents, a layer of not very well-del 

 cells with spherical nuclei investing their surface. 



