Deafness practically illustrated / [James Yearsley].

  • James Yearsley
Date:
[1849]
Catalogue details

Licence: Public Domain Mark

Credit: Deafness practically illustrated / [James Yearsley]. Source: Wellcome Collection.

    54/200 page 42
    When it does occur, paralysis of the acoustic nerve may be produced by pressure exerted on it in any part of its course between the sensorium and its expansion in the labyrinth, by tumours within the cranium; or its functions may be suddenly abolished by loud sounds, as thunder, or explosions of artillery, in the same manner as blindness is caused through excessive stimulus of the. optic nerve by intense light. Nervous deafness may be merely symptomatic of other diseases, as dyspepsia, or intestinal irritation from worms. Sumetimes it remains after an attack of apoplexy; it also arises from the con- vulsions of infants during dentition, and this latter variety is considered by Itard the least palliable of all kinds; probably, the greater number of cases of deaf- dumbness are of this description. Paralysis of the nerve of hearing, as a primary disease, is very rare, though it sometimes does occur. Itard believes para- lysis of the nerve may be caused by the shock, or the effects of the counter-stroke in falling from a con- siderable height. In some cases of deafness, alterations of structure have been discovered after death in the contents of the labyrinth—the cochlea, vestibule, and semicircular canals. Until within a comparatively recent period, a greater amount of incertitude has prevailed in the diagnosis of diseases of the ear, than in the diseases of any other organ of similar importance. This arose from the difficulty which the position and complexity of the organ offer to any attempt to connect the symptoms of its diseases with the structural lesions seen in post- mortem examinations, and in part from the diverse opinions which have been promulgated regarding the function of the various parts of the auditory apparatus.
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