But Professor Weldon cannot be warned. He told us the “law of dominance conspicuously fails for crosses between certain races.” Thence the start. I venture to give the steps in this impetuous argument. There are exceptions[153]--a fair number if we count the bad ones--there may be more--must be more--_are_ more--no doubt many more: so to the brink. Then the bold leap: may there not be as many cases one way as the other? We have not tried half the sorts of Peas yet. There is still hope. True we know dominance of many characters in some hundreds of crosses, using some twenty varieties--not to speak of other plants and animals--but we _do_ know some exceptions, of which a few are still good. So dominance 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:-- [153] If the “logician-consulting-partner” will successfully apply this _Fallacia acervalis_, the “method of the vanishing heap,” to dominant peas, he will need considerable leisure. “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.”