110 GLANDS. 



with those of the neighboring efferent vessels. By 

 this system of anastomosing vessels the capillary 

 network of the kidney is constituted, and the urinary 

 tubules are everywhere closely surrounded by it ; in 

 the cortical substance this network is very fine and 

 close (PL XX. fig. III. 5), but in the medullary cones, 

 its meshes grow longer, and the number of the vessels 

 diminishes (fig. III. 6). They continue to diminish in 

 number, and to increase in size, forming venous radi- 

 cles, which, assuming a straight course, ultimately 

 empty into the renal vein. 



Lymphatics. The origin of lymphatics from the kidney is imper- 

 fectly made out, and the same is true of the termina- 

 tions of its nerves, which enter the organ at its hilus 

 in company with its vessels. 



We may sum up the structure of the kidney in a 

 few words, as follows : from a papillary orifice a canal 

 takes its origin, which, leaving its sub-divisions out of 

 view, is rectilinear in the medullary cones, becomes 

 tortuous in the cortical substance, and ends there in a 

 flask-like pouch, in the interior of which the Malpi- 

 * ghian tuft is lodged. This takes its origin from one 

 of the interlobular arterial branches by means of the 

 afferent vessel, and itself gives off the efferent vessel, 

 which is the source of the capillary system of the 

 organ, by which its secreting tubules are enveloped, 

 and which pours its blood ultimately into the renal 

 vein. The secreting tubules have two walls : the one 

 thin and structureless, the other much thicker, and 

 consisting of a layer of epithelial cells which, at its 

 expanded extremity, are found covering the entire 

 surface of the Malpighian tuft. Nothing certain is 



