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A fan-shaped piece of vulcanite, the upper edge of which is pressed against the upper teeth; collecting the sound waves, it transmits them to the auditory apparatus by bone-conduction.

Rubber instrument held between the teeth to increase sense of hearing.

An instrument for enabling the deaf to hear; (1) A device for directing sound through the teeth, etc., to the auditory nerve; (2) an electrical device, resembling the receiver of a telephone instrument, which in churches, halls, etc., may be connected to a common telephone circuit, of which the transmitter si placed near the mounth of the speaker, while the receiver communicates the sound directly ot the ear of the hearer.

A device for aiding deafness.

Improperly formed from both Lat. and Gr. words. An instrument which, when pressed against the teeth, enables some deaf persons to hear by the bone conduction of sound. [Lat., Gr.]