A YEAK IN SCIENCE 123 



the number of students in the room. Determine the 

 number of cubic feet of air each individual receives per 

 hour. Has each individual the requisite amount of 

 air? If not, what change would you suggest to meet 

 the requirements? 



For your own information compute the volume of 

 your sleeping room in cubic feet. How long would 

 the air in the room suffice without change? What 

 means are there for changing the air in the room? 

 Are these sufficient? From what you have learned 

 above, correct the fault. 



CHAPTER XXI 

 EXCRETORY SYSTEM 



Exercise 82. The Kidneys. 



Object: To study the structure of a kidney. 



Apparatus 



Sheep kidney Scalpel 



Dissecting pan Scissors 



Directions: Describe the capsule surrounding the 

 kidney. Where is it attached to the kidney? Slit the 

 capsule on the convex side enough to allow the kidney 

 to be removed. Cut the kidney longitudinally from 

 the convex border toward the hilum sufficiently to open 

 the cavity within. 



What is the shape of the kidney ? Size ? Color ? How 

 many tubes do you find connected with this organ? 

 In the longitudinal section of the kidney notice two 



