THE URINARY ORGANS. 33! 



with the Malpighian corpuscles, situated in. the cortex between the 

 medullary rays, the tubule winds from the cortex to the medulla 

 and back again into the cortex, where it ends in a collecting tubule, 

 which passes to the medulla to terminate at the apex of a Malpig- 

 hian pyramid. The different portions of the tubules have the 

 following positions in the kidney : In the cortex between the medul- 

 lary rays are found the Malpighian corpuscles, the neck, the proxi- 

 mal and distal convoluted portions of the uriniferous tubule, and the 

 arched collecting tubules. The medullary rays are formed by the 

 cortical portions of the straight collecting tubules and a portion of 



' 



' Boundary line 

 between two 

 Malpighian 

 pyramids. 



r -*~~ Uriniferous 

 tubules. 



..CO 



Glomerulus. 



Fig. 268. Section through junction of two lobules of kidney, showing their 

 coalescence ; from new-born infant. 



the descending and ascending limbs of Henle's loops. The me- 

 dulla is made up mainly of straight collecting tubules of various 

 sizes and of the descending and ascending limbs and loops of 

 Henle's loops, the latter being often found in the boundary zone 

 between the cortex and medulla. (See Fig. 266.) The ascending 

 limb of Henle's loop of each uriniferous tubule, after it enters the 

 cortex, comes into close proximity with the Malpighian corpuscle 

 of the respective uriniferous tubule. 



