Licence: Public Domain Mark
Credit: The intermarriage of relatives and its consequences. Source: Wellcome Collection.
Provider: This material has been provided by King’s College London. The original may be consulted at King’s College London.
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![first cousins, 3 of first cousins once removed, 10 in which the grand-parents were [first] cousins, and 7 in which other degrees of consanguinity existed. We may conclude, then, that these Case Books furnish, in the parental history of 100 imbeciles, 5-l per cent, of consanguineous marriages.” V°. Sir Arthur Mitchell, writing in the interesting work already quoted, tells us of an inquiry which he instituted in a group of 299 parishes in Scotland :—• “ The whole number of idiots examined was 711. Of these 108 were illegitimate; the parentage of 84 was not known; the total number whose parentage was known, 519; in the cases of 421 the parents were not related, while in 98 cases the parents were related ... In order to believe that relationship does not influence the amount of idiocy, marriages of kinship would require in these countries to be to other marriages in the ratio of 1 to 7, which they notoriously are not. But in order properly to test this influence of consanguinity, we must at least deduct the cases of whose parentage I could obtain no information . . . Instead, therefore, of every seventh or eigth marriage in the community, we should require every fifth or sixth to be between persons related by blood to each other, in order to show that consanguinity of parentage does not influence the amount of idiocy.” If we assume that the marriages of relatives and non- relatives are in the ratio of one to two hundred, we cannot escape the conclusion that marriage “ within the forbidden degrees” entails upon the offspring at the very least a ten-fold liability to those dreadful disorders. It would be easy to multiply references and statistics supplied by Continental and American writers of eminence and experience; but our readers must take the assurance we give—that they are a mere repetition of those already set forth. All the world over, the intermarriage of cousins involves their unfortunate offspring in the same calamitous inheritances, and practically in the same proportion. DEAF-MUTISM. Many of the facts and some of the paragraphs in the following references to Deaf-Mutism, as a result of intermar- riage, are taken from the “ The Children of Silence,” an admirable work written by Dr. Seiss, Director of the'](https://iiif.wellcomecollection.org/image/b24761710_0011.jp2/full/800%2C/0/default.jpg)
