and with a larger proportion of children in the schools, it may be open to considerable doubt if the movement of this disease is really one of increase, though it seems that we are on the whole making no great headway against it. As to the minor diseases causing deafness, our statistics do not indicate just to what extent and in what direction deafness from them is being affected, and no precise conclusions can at present be set down. It is probable, however, that with the increased attention to children's diseases, as we have noted, there is really less deafness from most of them than formerly.[40] THE CONGENITALLY DEAF When we come to consider the question of congenital deafness, which comprises a little over a third of the total amount of deafness, we have an even more difficult problem on our hands, for here we are to deal with some of the great questions of heredity--though hereditary deafness and congenital deafness are not altogether one and the same thing.[41] For the purposes of our inquiry, let us think of the congenitally deaf as divided into three great classes in respect to their family relations: 1. the offspring of parents who were cousins; 2. the offspring of parents who were themselves deaf or members of families in which there are other deaf relatives; and 3. the product of families without either consanguinity or antecedent deafness. Of these three classes the first two only will engage our attention. Of the last, comprising, according to the census, nine-twentieths, or 44.4 per cent, of the congenitally deaf, there is not much that we can say. For a great part of it there no doubt exists in the parent, or perhaps in a more remote ancestor, some abnormal strain, physical or mental, in the nature of disease or other defect. But in respect to such deafness we have too little in the way of statistical data to help us arrive at any real determination; and for it as a whole we shall have to wait till we have greater knowledge of eugenics and the laws of heredity.[42] THE OFFSPRING OF CONSANGUINEOUS MARRIAGES Not all the deaf born of consanguineous marriages are congenitally deaf, but as the majority are so, and as the fact of the parents being blood relatives is assumed to have at least a contributing influence in the result, we may consider the matter in this place. It is in fact closely connected with the question of deaf relatives in general.