PHYSICAL CHARACTERS IN MAN 53 



Evidentl}^ what is required is an extensive collection 

 of accurate data based on careful measurements of 

 pigmentation with colour tops before this complex 

 subject can be fully understood. Probably something 

 more complicated than the two-factor hypothesis 

 of Davenport is required to explain all the facts of 

 colour inheritance in white-black crosses. In how 

 far real permanent blends occur remains to be seen. 

 Although individuals occur in later generations who 

 pass for whites, it is not certain that the pigment 

 is ever entirely lost, though it is probable that the 

 presence of other negroid features gives the impression 

 that more black pigment has been retained than in 

 the normal brunette skin. 



Jordan (191 1), in a histological stud}' of melano- 

 genesis in mulatto and white skins, finds that the 

 only factor in skin pigmentation is the number of 

 (yellowish-brown) granules and the number of cells 

 containing such granules. Some mulattoes are iden- 

 tical with negroes and others with brunettes in amount 

 of pigment. The apparent continuit}' in the melano- 

 genetic process is believed to rest in mulatto families 

 upon discontinuities or discrete units controlling the 

 production of melanin granules. Such conditions 

 conform more or less closely to an alternative mode 

 of inheritance. 



Sedgwick (1863) refers to silvery grey hair of very 

 coarse texture as being present in about one in ten or 

 twelve of the Mandan Indians, irrespective of age. 



The various types of hair in the different races of 

 man — straight, wav}', kink}', and curly — are known 

 to differ in the shape of a cross-section, straight hair 

 being circular in cross-section, kinky hair elliptical, 

 with the other t3'pes intermediate. Little is actually 

 known regarding the inheritance of these differences. 

 Bean (1908) has studied the hair types among the 

 h3'brid Filipinos, in which the Chinese element fur- 



