Page:EB1911 - Volume 07.djvu/907

Rh statistics of the duchy of Nassau, and of Berlin, both quoted by Dr Kerr Love (pp. 119, 120). These show 1 deaf person in 1397 Roman Catholics, 1101 Evangelicals and 508 Jews in the former case, and 1 in 3000 Roman Catholics, 2000 Protestants and 400 Jews in the latter. When we are told that “Roman Catholics prohibit marriages between persons who are near blood relations, Protestants view such marriages as permissible, and Jews encourage intermarriage with blood relations,” these figures become suggestive. We find the same greater tendency to deafness in thinly-populated and out-of-the-way districts and countries where, owing to the circle of acquaintances being limited, people are more likely to marry relations.

With regard to the question of marriages of the deaf, Professor Edward Allen Fay’s work is so complete that the results of his six years’ labour are particularly worthy of notice, for, as the introduction states, the book is a “collection of records of marriages of the deaf far larger than all previous collections put together,” and it deals in detail with 4471 such marriages. The summary of statistics is as follows (Marriages of the Deaf in America, p. 134):—

One point deserves special attention in the above list. It is that where there are no deaf relatives (i.e. where there has not been a history of deafness in the family) only one child out of twenty-four is deaf, even when the parents were both born deaf themselves. Where there were deaf relatives already in the family on both sides, and the parents were born deaf, the percentage of deaf children is seven and a half times as great. This seems to show that there are causes of congenital deafness which are, comparatively speaking, unlikely to be transmitted to future generations, while other causes of congenital deafness are so liable to be perpetuated that one child in every three is deaf. We conjecture that one original cause of congenital deafness which reappears in a family is consanguinity—for instance, the intermarriage of first or second cousins (hearing people) in some previous generation. Out of the 2245 deaf persons who were born deaf, 269 had parents who were blood relations, according to Fay. And perhaps many more refrained from acknowledging the fact. Eleven had grandparents who were cousins. This theory calls for investigation, and while the marriage of deaf people is not encouraged, it is fair to ask those who so strenuously oppose such unions whether they may not be spending their energies on trying to check an effect instead of a cause, and if that cause may not really be consanguinity,—witness the percentage of deaf people among Roman Catholics, Protestants and Jews before noticed. On the principle that prevention is better than cure it is the intermarriage of cousins and other relations which should be discouraged. The marriage of deaf people is inadvisable where there has been deafness in the family in former generations, but the same warning applies to all the other members of that family, for the hearing members are as likely to transmit the defect of which deafness is a symptom as the deaf members are. We are more concerned to discover the primary cause of the defect, and take steps to prevent the latter from occurring at all. Those who have no dissuasions for hearing people, who might perhaps cause the misery, and only give counsel to those among the transmitters of it who happen to be deaf, are acting in a manner which is hardly logical.

2. Post-Natal.—We have collected and grouped the stated causes of deafness in those partners of the marriages in America noticed by Fay. About a hundred and thirty did not mention how they lost hearing. Any errors in this calculation must be less than 1% at most, and can make no material difference. In some cases two or more diseases are given as the cause of deafness. In such cases where one is a very common cause of deafness, and the other is unusual, the former is credited with being the reason for the defect. Where both are common, we have divided the cases between them in a rough proportion.

We have counted a hundred and thirty of those who were returned as having lost hearing who were also stated to be the offspring of consanguineous marriages.