32 HEREDITY IN RELATION TO EUGENICS 



2. Hair Color 



This character is due to the presence of brown granules 

 in the hair and sometimes also to the presence of a diffuse 

 reddish pigment. The study of heredity of hair color is 

 complicated — more than that of eye color — by the fact i 

 that the hair grows darker with age, at least until maturity 

 is achieved. If you compare the light browns and the 

 blacks in children under 16 and over 16 you will find twice 

 as many light browns in the younger lot as in the older; 

 but only half as many blacks. In other words, half of the 

 persons who will eventually have black hair still have light 

 to medium brown at 16 years of age.^ While this tends to| 

 obscure the result yet the general fact of segregation in hair 

 color cannot be gainsaid. Let us examine the results of 

 various matings. (Table V). 



Table V 



The hair-color op the offspring of parents with different classes 



OF hair pigment. 



Offspring 

 All with tow, yellow, golden or red hair. 



HaK with light hair, half with brown; in 

 other families all children may eventually 

 gain brown hair 



Most children have brown hair; some (about 

 one-quarter) have light hair. In some 

 families all children eventually gain brown 

 hair. 



The most striking result is that dark-haired children prob- 

 ably never come from flaxen-haired parents. Indeed, a 

 good practical rule is that the children will not acquire hair 

 darker than that of the darker parent. 



The inheritance of red-hair color has a certain eugenic 

 importance. There can be little doubt that a young person 



1 Holmes and Loomis, 1909, p. 55. 



I 



