The intermarriage of relations / by Nathan Allen.

  • Allen, Nathan, 1813-1889.
Date:
1869
Catalogue details

Licence: Public Domain Mark

Credit: The intermarriage of relations / by Nathan Allen. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    and makes, as the result of his labors, the following- statement : 1. That while consanguineous marriages are only 2 per cent, of all marriages in France, the number of deaf mutes born of such marriages is to all deaf mutes— In Lyons, .... 25 per cent. In Paris, 28 “ In Bordeaux, ... 30 “ lie finds further: 2. That the danger of deaf and dumb offspring increases with the nearness of kinship between the parents; 3. That parents themselves deaf and dumb do not as a rule produce deaf and dumb offspring, and that the defect in such cases .is not therefore hereditary; and 4. That the number of deaf mutes increases in proportion to the local diffi- culties to freedom of cross-marrying. This proportion is in— France, . . . . 6 in 10,000 Corsica, 14 “ Alps, 23 “ Canton Berne, .... 28 “ There is some doubt, we think, whether mutism arises from this source oftener than certain other defects in the senses. As the brain and nervous system hold the foremost rank in the physical organi- zation in point of sensitiveness and vitality, it is the first to suffer by any derangements of a perfectly healthy, normal state of the system. As the senses of speech and hearing constitute the most important as well as conspicuous avenues to the brain, any defects in these organs would be sooner observed and their causes sought out. According to a great mass of facts collected on this subject, the functions of the brain seem to be affected far more than those of any other organ. Hence, a great number of weak or