A manual of aural surgery for the use of students and practitioners of medicine / by James Keene.

  • Keene, James.
Date:
1873
Catalogue details

Licence: Public Domain Mark

Credit: A manual of aural surgery for the use of students and practitioners of medicine / by James Keene. 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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    at wliicli tlie tick can be lieard, this constitutes a standard by wliicli we can judge tbe amount of diminution of bearing in disease. Watches, how- ever, differ so much in tone, and consequently in the distance at which they can be heard, that to describe a watch as being heard at so many inches from the ear really means nothing except as regards the par- ticular watch employed. I would therefore recommend keeping record in a manner very similar to that used in testing vision. Thus the watch may be repre- sented by the letter W, and supposing the distance at which it can be heard by the healthy ear be five feet, i.e. sixty inches, W |^ would express the normal hearing distance corresponding with the emmetropic condition of the eye. If in the case under observa- tion the watch can only be heard at one foot, i.e. twelve inches, ^ would represent the condition of hearing. In each case the denominator of the frac- tion indicates the number of inches at which the watch can be heard in health; the numerator, the actual distance in the case under examination. When the distance is less than an inch, the addition of a cypher to the denominator would express the quantity in tenths ; thus g-fo would represent half an inch, and so forth. Contact may be expressed ; pressure, and if not audible at all, This method possesses the advantage of showing at a glance the distance at which the watch should be heard as well as that at which it is heard. Thus, supposing that a watch, which under normal conditions can be heard at five feet, is only audible at one inch, we may conclude