THE KIDNEY. 



121 



we have previously seen of finely striated texture the medullary or 

 Malpighian pyramids. The cortical substance projects itself between 

 the pyramids, completely isolating them, forming the cortical columns. 

 Again observing the outer cortex, it will present narrow, light- 

 colored lines, which converge toward the pelvis; and, eventually, 

 pass into, and become a part of the Malpighian pyramids. These 



FIG. 85. DIAGRAM SHOWING THE PI.AN OF STRUCTURE OF THE HUMAN KIDNEY. 



light areas, made up of urine tubules, are the pyramids of Ferrein, or, 

 as sometimes called, the medullary radii. 



The darker spaces between the pyramids of Ferrein are called 

 labyrinths. 



The gross elements, to be understood before we proceed, then, are: 



1. The capsule of the kidney. 



2. The ureter. 



3. The pelvis with its three infundibula. The subdivision of each 



