78 THE MENDEL JOURNAL 



conditions, consanguineous marriages are apt to be 

 common. This we see in a marked degree in the 

 Scotch Highlands, where the inhabitants of many- 

 villages are nearly all cousins, in nearer or remote 

 relationship. We know that albinism is a recessive 

 character in animals, and we have just seen in the 

 negro marriage that it is so also in man. Individuals, 

 apparently quite normal externally, may, therefore, 

 carry albinism as a recessive character. So long 

 as such individuals marry a quite normal person 

 (one not carrying albinism recessive), albinism will 

 never appear among the offspring. But if they 

 marry another person similar to themselves — that is, 

 one carrying albinism recessive — ^then albino children, 

 as well as normal ones, will be born to them. So 

 that it may happen that in a long line of ancestry, 

 apparently normal all along, albinoes may quite 

 suddenly arise. That appears to be the explanation 

 of the case of Josephine Chassot. And the same 

 explanation suffices for the familiar fact that albinoes 

 are very often the offspring of a cousin marriage. 

 In these villages, where we may assume consanguineous 

 or endogamous marriages* were common, there must 

 have existed a certain proportion of the villagers 

 who were carrying albinism as a recessive character. 

 When two such married — and in random selections 

 this must now and then occur — albinoes are expected. 

 This, then, being the Mendelian expectation with 



* In this particular pedigree it is known that two normal brothers 

 married two normal sisters, all of the same village, and albinoes appeared 

 in the descendants of both. 



