No. 508] HEREDITY OF HAIR COLOR IN MAN 



195 



fancy mice and guinea pigs under the names of yellow, 

 chocolate and black are not fundamentally distinct, but 

 have probably been made so in the process of perfecting 

 the standard groups. Indeed, a casual acquaintance with 

 the variety of human hair color as one meets with it in 

 the streets of any large city shows that there are all inter- 

 grades between yellow, light brown, dark brown and black 

 hair and even the reds pass (through dark red and red 

 brown) into the warm browns. It may consequently be 

 concluded, at least provisionally, that there are two main 

 types of pigment in human hair; a reddish yellow, which 

 finds its intensest development in bright red, and a sepia 

 brown whose intensity varies from a light yellow to dark 

 brown and black. Finally, the two pigments may be 

 combined 2 and in such cases the brown pigment may quite 

 obscure the red. 



The conclusion here reached concerning the factors in- 

 volved in human hair color are not, we fear, in accord 

 with the recent investigations on other mammals. They 

 rather speak against the theory of well-developed unit 

 characters in human hair pigment. Brown and black 

 colors there are and an intensifier or a diluter; on the 

 other hand, these are not well denned units but occur m 

 all conceivable degrees. The facts of intensity in human 

 hair color indicate that the absence of selection made on 

 the basis of intensity has resulted in the blending of color 

 unit characters or has not afforded the selective means 

 by which thev have elsewhere been formed. 



General Scheme of the Tables.-The data concerning a 

 single family are placed in one line. At the extreme left 

 are given certain reference letters by which the family 

 is designated. Then follow the number of children m the 



designated family that have 



■ of the class named at 



the top of each column. The following six columns give 

 the color of the hair of the mother (M father (F), 

 mother's mother (MM), mother's father (MF), father b 

 mother (FM) and father's father (FF) so far as known. 



•It is clearl, seen in the hair of the .other of the Lyn fa.il, (Table 

 X, 6). 



