A manual of diseases of the ear / by George P. Field.

  • Field, George P (George Purdey)
Date:
1893
Catalogue details

Licence: Public Domain Mark

Credit: A manual of diseases of the ear / by George P. Field. Source: Wellcome Collection.

Provider: This material has been provided by The University of Leeds Library. The original may be consulted at The University of Leeds Library.

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    age of 08, there were among 1,210 congenital deaf-mutes (according to recent very exact statistics) 156, or 12'9 per cent., who were the offspring of consanguineous marriages; while among 1,551 individuals with acqixired deafness there were only 47, or 3 per cent., who sprang from such marriages. This positively proves that consanguineous marriages are a cause of congenital deaf-mutism. In Prussia the deaf-mute rate in families where father and mother are blood-relations is as follows:— Acquired deaf-mutism, 1 to each family, Congenital deaf-mutism, 166 to each family, which also proves that consanguineous marriages favour the birth of deaf-mute children. Wilde long since, from a careful analysis of statistics, formed the opinion that in only a small percentage of the offspring of deaf-mutes, even when the latter have intermarried, is the parents' defect reproduced. Thus, he found that to 86 deaf- mutes in Ireland, whose parents, with a single exception, could hear, there were born 203 children, of whom one only was a deaf-mute, and that out of the 13 children of 6 deaf-mute couples 12 were free from their parents' defect.* Hartmann shows from statistics by various authors that 28 children, all with perfect hearing, resulted from 17 marriages between deaf-mutes, and 489 of such children and 11 deaf-mutes (i.e., 22 per cent, of the total offspring) from 276 marriages where only one parent was affected. Among the parents of tlie 48 inmates of a deaf and dumb school in Manchester, in 1837, Holland ascertained that there was only one deaf-mute. Another writer statesf that, in 86 families having each a single parent congenitally deaf and dumb, 21 children, or about one-tenth of the whole number, were the subjects of deaf- mutism, and that in 24 families in which both parents were * Report on the Status of Disease, p. 13, 1854. See also Wilhelmi, quoted by Hartmann in Arch, of Otol., Dec, 1880. t Turner [? Eev. W. W,, of the U.S. America], quoted in Enc)/. Bri- tannica, loc. sup. cit.