Deafness

(děf'něs.) [A.S. deaf nes.] (Med.) Consider a blediminution or total lo of hearing. It may arise: 1. From a disease or some impairment of the auditory nerve; 2. From a partial or complete obstruction of the membrana tympani, the membrane which receives those vibrations of the air which constitute sound: this may be the result of disease or accident; 3. From disease of the o icles; 4. From a collection of wax in the auditory canal,preventing the due transmi ion of the vibrations to the membrana tympani; 5. From an enlargement of the tonsils, when they pre upon the Eustachian tube, - the canal which communicates with the middle ear. In most cases, however, the cause of the D. is not appreciable, and the treatment has to be purely empirical. [s. 268]