334 THE GENITOURINARY ORGANS. 



off, which break down into capillaries within the cortical substance. 

 Other arteries originate from the lower portion of the intralob- 

 ular arteries or from the arciform arteries themselves and enter 

 the medullary substance, where they form capillaries. These 

 vessels constitute the so-called " arteriolae rectae verae." Their 

 capillary system is in direct communication with the capillaries 

 of the vasa afferentia and "vasa recta spuria." The intralobular 

 arteries are not entirely exhausted in supplying the vasa afferentia 

 which pass to the glomeruli. A few extend to the surface of the 

 kidney and penetrate into the renal capsule, where they termin- 

 ate in capillaries which communicate with those of the recur- 

 rent, suprarenal, and phrenic arteries, etc. Smaller branches 

 from these latter vessels may penetrate the cortex and form 

 glomeruli of their own in the renal parenchyma (arteriae capsulares 

 glomeruliferae). These relations, first described by Golubew, are 

 of importance not only in the establishment of a collateral circula- 

 tion, but also as a partial functional substitute in case of injury to 

 the renal arteries. The same author also confirms the statements 

 of Hoyer (77) and Geberg, that between the arteries and veins of 

 the kidney, in the cortical substance, in the columns of Bertini, and 

 at the bases of the Malpighian pyramids, etc., direct anastomoses 

 exist by means of precapillary twigs. 



From the capillaries the venous blood is gathered into small 

 veins which pass out from the region of the medullary rays and 

 cortical pyramids and unite to form the "intralobular veins." These 

 have an arrangement similar to that of the corresponding arteries. 

 The venous blood of the labyrinthian capillaries also flows into the 

 intralobular veins, and as a result a peculiar arrangement of these 

 vessels is seen at the surface of the kidney where the capillaries 

 pass radially toward the terminal branches of the intralobular veins 

 and form the stellate figures known as the vena stellata. This sys- 

 tem is also connected with those venous capillaries of the capsule 

 which do not empty into the veins accompanying the arteries of the 

 capsule. The capillary system of the Malpighian pyramids unites 

 to form veins, the "venulae rectae," which empty into the venous 

 arches (venae arciformes) which lie parallel with and adjacent to the 

 corresponding arteries. The larger veins are found side by side 

 with the arteries and pass out at the hilum of the organ. 



Lymphatics of the kidney may be divided into superficial 

 lymphatic vessels, situated in the capsule, and deep ones, found in 

 the substance of the kidney. The deep lymphatic vessels need to 

 be investigated further. They form a network of closed lymphatic 

 vessels throughout the cortex. These empty, according to Rin- 

 dowsky, into larger lymphatics, which follow the intralobular ves- 

 sels ; and, according to Stahr, into larger vessels situated in the 

 medullary rays. The lymphatic vessels of the kidney proper 

 (deep vessels) leave this organ at the hilum. 



The kidneys receive their innervation through nonmedullated 



