174 



HEREDITY AND VARIATION 



large groups impracticable, and because the .proper place for such direct teaching 

 is in the home. It is, however, the function of biology to teach the primary facts 

 known about reproduction and heredity as applied in plant and animal breeding. 

 On these facts the child of to-day will build for the experiences of to-morrow. 



Problem 150 : To determine if there is individual variation 

 in any one measurement of the members of a given class. 



Materials. — String, ruler. 



Method. — With the string carefully measure the circumfer- 

 ence of your right wrist. 



Observations. — Verify your figures by having your neighbor 

 take the measurement for you. Do the same thing for him. The 



