'220 MICROSCOPIC ANATOMY OF THE ORGANS. 



more deeply lying glomeruli, and partly from the interlobular 

 or arcuate arteries. The meshes of the capillary network 

 which arises from these two sources and supplies the medulla 

 are elongated and surround the collecting tubules. The capil- 

 laries collect to form the venulce rectce, which end in the arcuate 

 veins. It must be noted also that the vessels of the kidney 

 parenchyma are in communication with those of the perirenal 

 fat by means of the vessels of the kidney capsule. A collateral 



FIG. 171. 



Transverse sectiou through the middle of the same kidney (Fig. 170), seen from above. 

 (Brodel.) The anterior branch of the artery supplies about three-quarters of the kidney 

 substance, while the posterior branch supplies only one-quarter. 



circulation is thus possible. There are also direct communi- 

 cations between the arteries and veins of the kidney (Hoyer, 

 Steinach, etc.). According to Brodel, the collecting veins 

 form anastomoses around the bases of the pyramids and around 

 the necks of the calyces. 



The lymphatics form a superficial plexus in the capsule and 

 a deep plexus, the vessels of which leave the kidney at the 

 hilurn. Anastomosing lymphatic spaces have been observed 

 connecting the two plexuses. 



The nerves accompany the blood-vessels into the kidney, 

 where they form plexuses around the uriniferous tubules. 

 According to Azoulay and Berkley, they penetrate the mem- 

 brana propria, and end by knob-like thickenings on the sur- 

 faces of the epithelial cells. 



