640 IMPROVEMENT OF LIVING THINGS BY MAN 



How to use our knowledge of heredity. Two applications of 

 this knowledge of heredity stand out for us as high school students. 

 One is in the choice of a mate, the other in the choice of a vocation. 

 As to the first, no better advice can be given than the old adage, 

 " Look before you leap." If this advice were followed, there 

 would be fewer unhappy marriages and divorces. Remember that 

 marriage should mean love, respect, and companionship for life. 

 The heredity of a husband or a wife counts for much in making 

 this possible. And, even though you are in high school, it is 

 only fair to yourselves that you should remember the responsibility 

 that marriage brings. You should be parents. Will you choose 

 to have children well born ? Or will you send them into the world 

 with an inheritance that will handicap them for life? 



Practical Exercise 19. Work out the inheritance of certain traits or peculi- 

 arities in your own family. 



Practical Exercise 20. Look up the history of one of the families mentioned 

 on page 639 and see what you can find out about their mental inheritance. 

 Use all sources of help, such as Davenport's Heredity in Relation to Eugenics, 

 Walter's Genetics, or Guyer's Being Well Born. 



Self-Testing Exercise 



Feeble-mindedness could be stamped out if (1) of such 



persons could be (2) . Blood or (3) count, as is 



proven by the (4), (5), and (6) families. 



Parasitism in (7) is largely caused by the (8) or 



socially unfit people. The science of being well born and (9) 



iscaUed (10). 



Review Summary 



Test your knowledge of the unit by: (1) rechecking on the survey ques- 

 tions ; (2) performing all assigned exercises ; (3) checking with your teacher 

 on all tests and trying again the ones you missed ; (4) making an outline of the 

 unit for your workbook. 



Test on Fundamental Concepts 



In vertical column under the heading CORRECT write numbers of all statements you be- 

 lieve are true. In another column under INCORRECT write numbers of untrue statements. 

 Your grade = right answers X 2 5. 



I. The environment (1) may change the form and traits of a plant 

 or an animal; (2) affects the offspring of plants and animals; 



