THE 



AMERICAN NATURALIST 



Vol. XLIII April, 1.909 No. 508 



HEREDITY OF HAIR COLOR IN MAN 

 GERTRUDE C. DAVENPORT and CHARLES B. DAVENPORT 



Station for Experimental Evolution, Carnegie Institution 

 op Washington 



Introduction 



Types of Hair Color.— The heredity of hair color in 

 mammals is a subject of great complexity, not to be 

 lightly entered upon. It is a subject in which much 

 knowledge has been gained in recent years through 

 the work of Bateson and his associates, Castle and 

 his pupils, Cuenot and others. Nevertheless certain 

 important points remain uncertain. First, and funda- 

 mental for our purpose, is the question of the number 

 of factors involved in any hair color. All are agreed 

 that there is a special red pigment (a lipochrome) that 

 stains the hair diffusely. In clear red hair one sees, in 

 sections, a yellowish red tinge that is not bound up with 

 any structures. With a high power one sees elongated, 

 spindle-shaped bodies, which are apparently the remains 

 of nuclei and are devoid of granules. In all other hair 

 (except that of albinos) one sees granules grouped in the 

 spindle-shaped bodies. In black hair (Chinaman, Fig. 

 A) these granules are large and numerous in each group 

 (average, 12) and appear of a dark brown color. In very 

 dark brown hair (negro, Fig. B) the granules are perhaps 

 a little larger but much less numerous in each group 

 (average, 6) ; and the color is a much less intense brown. 

 In hair of a cold, mouse brown (Fig. C) (about No. 25 in 

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