certainly be dealt with on the lines indicated by our principles.[47] =Other cases.=--So far we have considered exclusively diseases and disorders of the brain, the question of alcoholism being deferred to a special chapter. When we come to other forms of defect or disease we find a long gradation of instances: at the one extreme being cases where the fact of disastrous inheritance is palpable and inevitable, whilst at the other extreme are kinds of disease and defect as to which the share of heredity is still very uncertain. In some instances, then, the eugenist is bound to lay down the most emphatic propositions, as, for instance, that parenthood on the part of men suffering from certain diseases is and should and must be regarded and treated as a crime of the most heinous order: whilst in other instances all we can say is that here is a direction in which more knowledge is needed. Some particular cases may be referred to. The diseases known as Daltonism or colour-blindness, and hæmophilia or the “bleeding disease,” are certainly hereditary. The sufferers are usually male, but the disease is commonly transmitted by their daughters (who do not themselves suffer) to their male descendants. As regards colour-blindness, the defect is evidently insufficient to concern the eugenist, but hæmophilia is a serious disease, the transmission of which should not be excused. It may seem hard to assert that the daughter of a hæmophilic father should not become a mother, she herself being free from all disease. But it has to be remembered that the possibility of this hardship depends upon the fact that a hæmophilic man has become a father, as he should not have done. This point, as to the amount of hardship involved in the observance of negative race-culture, has always to be kept in mind. If negative eugenics were generally enforced upon a given generation some persons would, of course, suffer in greater or less degree from the disabilities imposed upon them. But their number would depend upon the neglect of eugenics by previous generations, and _thereafter the number of those upon whom our principles pressed hardly would be relatively minute_.