Sense of hearing.—Organ of hearing.—External ear; pavilion of tie ear, auditory canal.—Middle ear; tympanum, drum, or membrane tympani, fenestra ovalis, fenestra rotunda, Eustachian tube, the small bones of the ear, muscles and movements of the small bones.-Internal ear; labyrinth, vestibule, semicircular canals, cochlea, membranous labyrinth.—Auditory nerve.—Noises and sounds; duration, pitch, intensity and quality of sound; passage of sound through air, water, solid bodies; gravity, sharpness of sound.—Mechanism of heating; functions of different parts of the ear; movement of sounds in the ear; propagation of sounds to the auditory apparatus by the vibrations of the bones of the skull.—Opinions of physiologists on the Junctions of different portions of the labyrinth; theory of Helmholtz.—Fineness and delicacy of hearing.— Correctness of the ear.—Estimation of the intensity, the distance, and the direction of sounds; ventriloquism.—Duration of auditory impressions.—Sensations having an internal origin.—Parallel between the eye and ear.

The Ear

The organ of hearing is not placed on the face, like those of sight, smell, and taste; but in the thickness of the base of the skull. But we may say it belongs to the face as one of the elements of the physiognomy, by its external apparatus, which contributes to the expression of the head. The ear is divided anatomically into three regions—the external, middle, and internal ear.