STRUCTURE OF THE KIDNEY. 353 



ent vessel, comparable to a minute vein, which leaves the 

 Malpighian capsule just by the point at which the afferent 

 artery enters it. On leaving, it does not immediately join 

 other small veins as might have been expected, but again 

 breaking up into a network of capillary vessels, is distributed 

 on the exterior of the tubule, from whose dilated end it had 

 just emerged. After this second breaking up it is finally col- 

 lected into a small vein, which, by union with others like it, 

 helps to form the radicles of the renal vein. 



The Malpighian capsule is lined by a layer of fine squamous 

 epithelial cells ; but whether the small glomerulus or tuft of 

 capillaries in the interior is covered by a similar layer is un- 



FIG. 124. FIG. 125. 



FIG. 124. Plan of the renal circulation in man and the Mammalia, a, terminal 

 branch of the artery, giving the terminal twig 1, to the Malpighian tuft m, from 

 which emerges the efferent or portal vessel, 2. Other efferent vessels, 2, are seen 

 entering the plexus of capillaries, surrounding the uriniferous tube, /. From the 

 plexus, the emulgent vein, v, springs. 



FIG. 125. Semidiagrammatic representation of a Malpighian body in its relation 

 to the uriniferous tube (from Kolliker) -y-. a, capsule of the Malpighian body; d, 

 epithelium of the uriniferous tube ; e, detached epithelium ; /, afferent vessel ; g, 

 efferent vessel ; k, convoluted vessels of the glomerulus. 



certain. Kolliker believes that such a covering, although ex- 

 ceedingly thin, is present, and has delineated the appearance 

 in the accompanying diagram (Fig. 125). 



Besides the small afferent arteries of the Malpighian bodies, 

 there are, of course, others which are distributed in the ordi- 

 nary manner, for nutrition's sake, to the different parts of the 

 organ ; and in the pyramids, between the tubes, there are nu- 



