LESSON XXII. 

 STRUCTURE OF THE KIDNEY. 



1. a. Take a sheep's kidney and cut it in half 

 longitudinally, note the ureter expanding 

 into the pelvis and then into several tubes, 

 the calices, into which the pyramids project. 



b. On the cut surface of the kidney, note the 

 pale inner or central medulla formed by the 

 pyramids of Malpighi ; externally the cortex 

 a brownish-red zone having thin pale radial 

 stripes (cp. 2, c) which do not quite reach 

 the surface; and between the medulla and 

 cortex the intermediate layer forming a 

 dark red zone not very sharply denned, es- 

 pecially on the cortex side, and having pale 

 stripes (cp. 2, 6) continuous with those seen 

 in the cortex running radially through it from 

 the medulla. 



c. Turning back to the ureter, note the connec- 

 tion of its outer connective tissue coat with the 

 fibrous coat of the kidney, follow the renal 

 artery and vein running into the kidney in 



