724 



THE AMERICAN NATURALIST [Vol. XLIV 



country, penetrated by a railroad, we find, as in the 

 P. W. family, a large proportion of consanguineous mar- 

 riages. The argument against the probability of unions 

 with recessive albinism has not yet been presented with 

 any force. 



The third point— the lack of statistical accord between 

 the results of human breeding and those of animals— has 

 been often remarked upon. Bateson (1909, p. 28, foot- 

 note) believes the descent of albinism in man to be com- 

 plicated by some unascertained disturbance. A careful 

 consideration and analysis of the statistics indicates, I 

 think, that this disturbance is to be found in the method 

 of collecting the statistics. From the matings of two 

 persons that are simplex in pigmentation, two sorts of 

 families are to be expected, namely, those with albinos 

 and those without. Since in the long run, from such 

 parents, only one albino is produced in four offspring, it 

 is clear that the chances are that in all families of one, 



TABLE XII 



