BLENDED INHERITANCE 181 



unnecessary to discuss the authenticity of these cases ; if 

 they exist, they are obviously rare exceptions. If they 

 rarely exist, an explanation of these rare exceptions must be 

 found which is in accordance with what generally happens, 

 and what generally happens is that the colours of the two 

 races blend. Francis Galton, writing of the blending of 

 the black and white colours in man, says : " If the white- 

 ness refuse to blend with the blackness, some of the off- 

 spring of the white man would be wholly white and the 

 rest wholly black. The same event would occur in the 

 grandchildren mostly, but not exclusively in the children 

 of the white offspring, and so on in subsequent generations. 

 Therefore, unless the white stock became wholly extinct, 

 some undiluted specimens of it would make their appear- 

 ance during an indefinite time, giving it repeated chances 

 of holding its own in the struggle for existence." l Whether 

 the exceptions that are claimed are valid or not, it is quite 

 evident that segregation is not what generally happens. 

 When there is a trace of black blood in a white family 

 it does not manifest itself by the appearance of apparently 

 pure-bred negroes. What we see is a mixture of the char- 

 acters proportionate to the nearness of the negro ancestry. 

 Of course there are variations, and a child may show negro 

 characters more strongly marked than they were in the 

 immediate parent through whom the negro blood came, 

 but nevertheless the child is never as black as the pure- 

 bred negro, and it takes a very long time of mating with 

 the pure white race for a negro strain to be swamped. It 

 is the same with a great many characters in other crosses. 

 Frequently the hybrids when inbred preserve the blended 

 characters, and the offspring do not tend to revert to the 

 characters of either parent. Even Mendel's experiments 

 showed that characters did not always segregate in the 

 same way as did the characters in the case of the peas, 

 and there are many other cases, some of which have been 

 described already. 2 



1 Galton, Natural Inheritance. a See pp. 176-7. 



