The Pamphlet Collection of Sir Robert Stout: Volume 38
The Audiphone and Dentaphone
The Audiphone and Dentaphone.
The Chicago Audiphone can be used at the opera or church or in general conversation with perfect comfort and success. I think the form (fan-shape) is quite an item, as it is easily carried, and can be used without exeiting comment. The position of holding a fan in the mouth is quite a natural one.
The principle of the working of the Audiphone is very simple. The instrument only does good in cases of deafness the result of external and middle-ear diseases. Where the nerve is involved it is useless. The instrument is held between the teeth. The sound striking it causes certain vibrations, which are carried through the bones to the nerve of hearing. In case of the patient having artificial teeth, the conducting power is of course interfered with very much.
Patients before investing in an Audiphone should make certain tests, unless they have an instrument at hand to try. If on placing the handle of a tuning fork (which has been caused to vibrate by striking it on the knee) on the teeth, the ringing is heard distinctly, or with increased intensity; or if a watch held firmly between the teeth is heard to tick well, it is pretty certain that an Audiphone will be of some service to them. Patients in whom there is any prospect of improvement of hearing by treatment should not use an instrument except on special occasions.
Mrs. P., who is unable to hear only when the voice is considerably elevated and the mouth put close to the ear, purchased a Chicago Audiphone. The result was surprising. She can hear common conversation at some distance with it. Others I have tried with like result. My Audiphone cost $10.50.