Deafness practically illustrated / [James Yearsley].

  • James Yearsley
Date:
[1849]
Catalogue details

Licence: Public Domain Mark

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

    46/200 page 34
    closed, the Eustachian tubes become dilated, and a sufficient quantity of air passes into the tympanum to force its membrane outwards. On the other hand, if the sucking motion be imitated, the mouth and nostrils remaining closed as before, the air of the tympanum is rarified, and decreased in quantity, the tubes becoming closed by the collapse of their parieties, and the mem- brane forced inwards by the pressure exerted on its ex- ternal surface by the atmospheric air. Under either of these circumstances, whether the membrane be affected by excess or deficiency of air, deafness ensues, and con- tinues until both membrane and tube return to the natural condition. ‘The same principle obtains in the deafness generally observed towards the termination of fevers, and always held to be a favourable symptom. Here, the cause lies in the return of the secretions to the mucous membranes, as the disease subsides; and the deafness is occasioned by the temporary obstruction of the tubes with the excess of mucus secreted. The effect of pressure of the atmospheric air in forcing in the tympanum and causing deafness is shown most satisfactorily in a case recorded by Deleau. While operating on a gentleman, in whom catheterism of the tube immediately effected a restoration of the hearing, which had been lost for nine years, Deleau found, that while the catheter remained firmly fixed in the tube, he was able by means of a syringe to exhaust at will the cavity of the tympanum, and so re-establish the deaf- ness, which disappeared the moment air was again ad- mitted, and the equilibrium restored. There is a peculiar circumstance connected with deaf- ness arising from the state of the membrana tympani
    No text description is available for this image
    No text description is available for this image
    No text description is available for this image