Page:Memoir upon the formation of a deaf variety of the human race (microform) (IA cihm 08831).pdf/9

4 MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. Such a conclusion, however, would be incorrect; and I desire to direct attention to the fact that in this country deaf-mutes marry deaf-mutes.

An examination of the records of some of our institutions for the deaf and dumb reveals the fact that such marriages are not the exception, but the rule. For the last fifty years there has been some selective influence at work which has caused, and is still causing, the continuous selection of the deaf by the deaf in marriage.

If the laws of heredity that are known to hold in the case of animals also apply to man, the intermarriage of congenital deaf-mutes through a number of successive generations should result in the formation of a deaf variety of the human race.

On the other hand, if it can be shown that congenitally deaf persons marry one another without any greater liability to the production of deaf offspring than is to be found among the people at large, then it will be evident that we cannot safely apply to man the deductions that have been drawn from experiments upon animals.

There are good grounds for the belief that a thorough investigation of the marriages of the deaf and the influence of these marriages upon the offspring will afford a solution of the problem, "To what extent is the human race susceptible of variation by selection?"

Although the statistics I have been able to collect are very incomplete, I have ventured to bring the subject to the attention of the Academy, in the hope that the publication of the results so far obtained may lead to the completion of the statistics.