It may be assumed that the genetic factors that are instrumental in producing the secondary sexual characters have also other but unknown influences in the economy of the species, color and ornamentation being by-products of these factors whose utility in other directions accounts for their presence. Such a philosophy has perhaps one redeeming feature, since it suggests the possibility of searching for other influences--influences that only incidentally give the striking coloration and ornamentation of the males. At first sight the absence of cock-feathering in the Sebright may seem to furnish the occasion for such a quest. It might appear that since only one or two genetic factor differences are responsible for the “nuptial” plumage of the male, that this plumage may have originated in one or two genetic changes. Such an argument is fallacious, however, for very many genetic factors may historically have been necessary to build up the nuptial plumage of the male. The breeding experiment shows no more than that one or two other factors have appeared that counteract the effect of all that the others are capable of producing; the experiment throws no light upon how many or how few these other factors may be. That the nuptial complex is still present in the Sebright is evident after castration. Castration shows only that the testes in the Sebright produce some material that keeps down the effects of all the other factors combined. This conclusion, it is true, somewhat simplifies the problem for those who appeal to natural selection as suppressing in the female the feathering of the cock, because it shows that this could have been accomplished by one or two Mendelian factors that appeared of such a kind that they caused the ovary to produce a substance antagonistic to the influences coming from the genetic complex of the species. With this by way of provisional exposition, let us return to the question as to whether the Sebright-game cross throws any other light on the possibly useful character of the genetic factor or factors that produce cock-feathering. It is obvious that the evidence gives us no clue at all, for with the exception of the normal allelomorphs of the dominant factor for hen-feathering, all the other factors are still present in the Sebright. The normal allelomorph in question need not have had any relation to the other complex; in fact, it seems not to have any, because the castrated Sebright (with both normal allelomorphs replaced by genes for hen-feathering) still develops the characteristic cock-feathering.