A text-book of the diseases of the ear and adjacent organs / by Dr. Adam Politzer ; translated from the third German edition by Oscar Dodd ; edited by Sir William Dalby.

  • Politzer, Adam, 1835-1920.
Date:
1894
Catalogue details

Licence: Public Domain Mark

Credit: A text-book of the diseases of the ear and adjacent organs / by Dr. Adam Politzer ; translated from the third German edition by Oscar Dodd ; edited by Sir William Dalby. Source: Wellcome Collection.

Provider: This material has been provided by the Harvey Cushing/John Hay Whitney Medical Library at Yale University, through the Medical Heritage Library. The original may be consulted at the Harvey Cushing/John Hay Whitney Medical Library at Yale University.

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    lower we go in the scale. The failure of the lower tones is therefore very important for the diagnosis of middle ear affections, especially when other symptoms fail. Although clinical observation also gives that, in general, in middle ear affections, high tones are better heard than lower ones, still, on account of the frequent exceptions, it is only to be depended upon in connection with the general result of the examination of the patient. Positive results are only given of the presence of hindrances to sound conduction, as with these it is very exceptional that low- toned tuning-forks are heard far down in the scale. Less dependence can be placed upon the testing with high tones, as in middle ear affections with greatly diminished hearing, the perception for the upper tones of the scale may also be lacking (Burckhardt-Merian, Rohrer). On the other hand, in marked cases of disease of the auditory nerve, the perception for the lower tones may be entirely wanting, while, according to my own observation, very often high tones, up to nearly the limit of the capability of perception, are distinctly heard. For the testing of the perception of the lower tones, c = 128, is sufficient for the examination of most cases, but in some cases C-1 = 64 and C-2 = 32 should be used for examination. For the testing of the perception of the higher tones the tuning-forks should be used, c4 or c5 (2,048 and 4,096), and for the testing of the upper part of the scale Galton's whistle (brought into use by Burckhardt-Merian in 1878) is used. Galton's whistle consists of a small, covered, cylindrical whistle which is lengthened and shortened by a valve moved with a micrometer screw. The lower portion of the valve is in connection with a hollow cylinder which extends over the cylinder of the whistle. On the side of the whistle is a scale to show the tens, and around the hollow cylinder a scale to show the single numbers. The blowing on the whistle is done by a small rubber balloon connected with it. According to Burckhardt-Merian the Galton whistle has a compass of more than the three uppermost octaves with 6,481-84,000 vibrations to the second. This instrument is specially suited for testing the capability of perception for the high tones. Above the limit to which the perception of our auditory nerves responds for the highest notes, vibrations are proved by the response of a sensitive gas flame. Besides the Galton whistle, Blake, Burckhardt-Merian, and Rohrer recom- mend for testing the upper limit of the perception of hearing, a series of Konig's cylinders of 20,000 to 100,000 vibrations in the second with intervals of 5,000 vibrations. The diameter of the sounding tubes is about 20 mm., and their lengths vary according to the different tones of the series. Appun's apparatus for testing the upper tone limit consists of 11 tuning-forks of 2,000- 50,000 vibrations (Kessel). The forks are set in vibration with a violin bow. Testing with high-pitched timing-forks and with Galton's whistle will only give a good result when the difficulty of hearing affects both sides and has pro-