288 



HEREDITY AND ENVIRONMENT 



III. Mendelian Inheritance in Man 



The study of inheritance in man must al- 

 ways be less satisfactory and the results less 

 secure than in the case of lower animals and 

 for the following reasons: In the first place 

 there are no "pure lines" but the most compli- 

 cated intermixture of different lines. In the 

 second place experiments are out of the ques- 

 tion and one must rely upon observation and 



P^iG. 64. Blending inheritance of skin color in negro — 

 white cross with dominance of kinky hair over straight hair. 

 (From Bond.) 



