6 HEREDITY [ch. i 



the action of circumstances are inherited. Does a 

 man, for instance, who develops certain muscles by 

 frequent use, or who injures his health by excessive 

 drinking, have children with larger muscles or poorer 

 health in consequence? The question is frequently 

 answered in the affirmative, but it is part of the 

 province of the study of heredity to investigate the 

 matter, and in these and all other cases to decide 

 not only whether a character is inherited, but, if it is, 

 to what extent and in what manner it will appear in 

 the offspring. 



