20 HEREDITY OF SKIN COLOR IN NEGRO-WHITE CROSSES. 



From tables 8 and 8a it is clear that, by hypothesis, the germ-cells 

 of neither parent contain the factors for black; hence none of the off- 

 spring should exceed grade ii per cent of N, and none do. There is, 

 however, one case that stands by itself and is placed in table 8a. The 

 father in this case was dead. His skin is said to have been so fair that 

 he would have passed anywhere for white. His mother's mother was 

 a "colored" woman and his mother a very fair colored woman with 

 blue eyes; his father and mother's father were British. The mother, 

 who had a skin-color formula 7, 46, 23, 24, was bom of a brunet mother 

 of East Indian and French origin by a very fair colored father. There 

 are 8 children, of whom 2 have N 19 per cent and i N 15 per cent, 

 which are typical "light-colored" grades of pigmentation. This case 

 might be taken as illustrating the view, so widely held in America, 

 that two whites, of whom at least one is of colored origin, may have 

 a dark-skinned child by reversion. This view has no scientific founda- 

 tion, and certainly the present case can not be regarded as critical, for 

 there are too many unknown factors. The case probably belongs to 

 table 9, the mother carrying ,one factor for black which has become 

 faded with age, as she is over 40. The result favors this assumption, 

 since there is an. approximate equality of skin. colors of the gxades 

 without any factor and with one factor for black. 



Tabic p. — In the father all gametes are without factor for N; in 

 the mother half have one such factor; expectation is an equal number 

 of zygotes with no factor for N and one factor for N ; actually there is 

 a not highly improbable excess of the darker offspring. Opposed to 

 expectation is one case of a child of 7 years with skin color N 29 per 

 cent who appears to be legitimate and whom we must regard as an 

 extreme fluctuate, having passed the arbitrary boundary of its class 

 by 4 per cent. 



Table 10. — In this case the gametes of the father contain no factor 

 for black; of the gametes of the mother, one out of four has 2 factors, 

 two have i factor, and one has no factor and the children should have 

 these factors in these proportions. There is another possibility, but 

 it will not often be realized, namely, that the medium-colored parent 

 has one factor (e.g., the A factor) duplex and the other {B) factor 

 absent. This combination will be found in one-eighth of the offspring 

 derived from two strict mulattoes and, in larger proportions, from other 

 matings. The actual results favor the conclusion that in this case the 

 gametes of the "mulatto" parent were of the above-mentioned three 

 kinds in respect to the number of factors for N. The actual distribu- 

 tion agrees fairly well with expectation based on this assumption, except 

 that there is one child with skin color N 50, who doubtless has 3 

 factors for black. This girl is probably illegitimate, although both 

 parents assert that she is not. She is the only one of her fraternity who 

 has kinky hair. The mother's hair is curly and the father's is straight. 



