Notice of several cases of malformation of the external ear, and of experiments on the state of hearing in such persons, / by Allen Thomson ... Together with an account of the dissection of a similar case of malformation / by Joseph Toynbee.
- Allen Thomson
- Date:
- 1847
Licence: Public Domain Mark
Credit: Notice of several cases of malformation of the external ear, and of experiments on the state of hearing in such persons, / by Allen Thomson ... Together with an account of the dissection of a similar case of malformation / by Joseph Toynbee. Source: Wellcome Collection.
Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.
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![in this manner more perfectly heard by these individuals than by other persons. It must be obvious that from the nature of their defect, the persons affected with closure of the meatus, must labour under considerable difficulty in distinguishing accurately different degrees of intensity of sound; but it does not appear that in any of them, there is any want of the power to distinguish its other qualities, as timbre or pitch. The lad B. had a range of hearing, apj)arently as extensive as that of other persons, he having been tried in Mr Forbes’ room, with a range of sounds extending from one very low in the scale to one four octaves above the middle C of the ])iano- forte, and he was perfectly able to distinguish the pitch of different notes. The difference in the direction of sounds, he appeared to have very little, if any, power of distinguishing; but this is not more than we should expect, for most persons can tell the direction from which sounds proceed very imperfectly Indeed, when the ears are stopped. Our knowledge of the direction of sounds, in fact, depends in a great measure upon our judgment of the difference of intensity with which one or other ear is affected by them; or when one ear only is employed, by the motion of the head till the axis of the open meatus is brought exactly into the direction of the quarter from whence the sound proceeds, when it is heard with greatest intensity. But so completely devoid was the lad B. of any such faculty, that he generally referred all sounds to the direction of the vertex of the head, as the place where he appeared to hear them most intensely. This remark with respect to the power of distinguishing the direc- tion of sounds, leads me to consider next the history of the persons with closed meatus, in reference to their hearing with one or both ears. Even in those whose hearing is perfect, the cars exhibit great inferiority to the eyes, in separating or distinguishing sensations, which affect, simultaneously, the organs of the two sides. Dr Wells, founding upon what is observed to occur in vision, imagined that if two different sounds could be heard separately, each one by a different ear, such sounds would not coalesce; but Dr John Gordon, arrived at a different conclusion, and, I believe rightly. The individuals before us, present conditions in which there is almost a total impossibility of the opposite ears being differently affected by simultaneous sounds, so much so, indeed, that the lad B. never appeared to have conceived the organs of hearing to be double, or to have distinguished one from the other. Nor, indeed, was he aw'are that the seat of hearing was in that part of the head, which is occupied by the internal ear ; but w'as in the habit, when listening attentively, of placing the flat part of his hands upon the sides of his head so as to cover his imperfect ears, and of directing](https://iiif.wellcomecollection.org/image/b24931330_0018.jp2/full/800%2C/0/default.jpg)
