192 A Defence of Mendel's 



may yet be all a myth, built up out of the petty facts those 

 purblind experimenters chanced to gather. Let us take 

 wider views. Let us look at fields more propitious more 

 what we would have them be ! Let us turn to eye-colour : 

 at least there is no dominance in that. Thus Professor 

 Weldon, telling us that Mendel "had no proper basis for 

 generalisation about yellow and green peas of any ancestry," 

 proceeds to this lamentable passage :- 



" Now in such a case of alternative inheritance as that of 

 human eye-colour, it has been shown that a number of pairs of 

 parents, one of whom has dark and the other blue eyes, will 

 produce offspring of which nearly one half are dark-eyed, nearly 

 one half are blue-eyed, a small but sensible percentage being 

 children with mosaic eyes, the iris being a patch-work of 

 lighter and darker portions. But the dark-eyed and light-eyed 

 children are not equally distributed among all families ; and it 

 would almost certainly be possible, by selecting cases of marriage 

 between men and women of appropriate ancestry, to demonstrate 

 for their families a law of dominance of dark over light eye-colour, 

 or of light over dark. Such a law might be as valid for the 

 families of selected ancestry as Mendel's laws are for his peas 

 and for other peas of probably similar ancestral history, but it 

 would fail when applied to dark and light-eyed parents in 

 general, that is, to parents of any ancestry who happen to 

 possess eyes of given colour." 



The suggestion amounts to this : that because there 

 are exceptions to dominance in peas ; and because by some 

 stupendous coincidence, or still more amazing incompetence, 

 a bungler might have thought he found dominance of 

 one eye-colour whereas really there was none*; therefore 



* I have no doubt there is no universal dominance in eye-colour. 

 Is it quite certain there is no dominance at all? I have searched 

 the works of Galton and Pearson relating to this subject without 

 finding a clear proof. If there is in them material for this decision 



