434 HEREDITY AND ENVIRONMENT 



apply and are of more doubtful value. Of 

 course compulsory measures are out of the 

 question and encouragement and advice alone 

 are feasible. Giving advice regarding matri- 

 mony is proverbially a hazardous performance, 

 and it is not much safer for the biologist than 

 for others. With much more complete knowl- 

 edge regarding human inheritance than we 

 now possess it may ultimately be possible to 

 give such advice wisely, especially with respect 

 to physical characteristics which are hereditar- 

 ily simple and generally of minor significance. 

 But where the character is an extremely com- 

 plex one as in intellectual ability, moral recti- 

 tude, judgment and poise, which are the chief 

 characteristics which distinguish the great man 

 from his fellows, it will probably never be pos- 

 sible to predict the result before the event. 

 He would be a bold prophet who would un- 

 dertake to predict the type of personality which 

 might be expected in the children of a given 

 union. Some very unpromising stocks have 

 brought forth wonderful products. Could 

 anyone have predicted Abraham Lincoln from 

 a study of his ancestry? Observe I say "pre- 



