THE KIDNEY 



425 



pars radiata of the cortex. They contain straight portions of the urinif- 

 erous tubules; these are continuous with the similar tubules in the 

 boundary zone of the medulla. These columns lie within the cortex and 

 not, as their name might be taken to indicate, in the medulla. They 

 are termed 'medullary rays' 

 because of their peculiar rela- 

 tion to the medulla, from 

 which they extend outward in 

 a radial direction. It would 

 seem more proper to desig- 

 nate them 'cortical rays.' 



That portion of the cortex 

 which invests the cortical 

 rays and which includes all 

 the remaining cortical por- 

 tions of the organ, consists of 

 extremely tortuous tubules, 

 and is characterized by the 

 presence of small globular 

 bodies, each of which con- 

 tains a tuft of capillary ves- 

 sels. These are the renal 

 corpuscles (Malpigliian bod- 

 ies] which are characteristic 

 of the kidney. The portion 

 of the cortex in which they 

 occur includes the entire cor- A 



tical substance with the ex- FIG. 398. DIAGRAM OF THE STRUCTURE OF 

 ception of the cortical rays, THE KlDNEY - 



and is known as the renal Papillary zone, and b, boundary zone of 

 , 7 . , the medulla; c, cortex; 1, apex of a renal 



labyrinth or pars convoluta. pyramid; 2, capsule; 3, tubules of the me- 

 The labyrinth is divided dulla; 4, vasa rectse; 5, vascular arcades; 6, a 

 into: (1) the renal columns, cortical ray; 7, labyrinth; * interlobular ar- 

 tery; 9, renal corpuscle; 10, 'cortex corticis.' 

 already mentioned; (2) the (After Testut.) 



intercolumnar portions, or 



labyrintli proper, which includes that portion of the labyrinth which 

 invests the cortical rays, and which, in sections cut parallel to these 

 columns (longitudinal sections) appears as a portion of cortex inserted 

 between the adjacent rays; (3) a narrow boundary zone of the cortex, 

 'cortex corticis of Hyrtl, which is included between the fibrous capsule 



