“The state of the epidermis, the ceruminous glands and secretion, the dermis, periosteum and bone is to be noticed. The outer surface of the membrani tympani is then to be examined; also the state of its epidermoid and dermoid laminæ, its degree of tension, and the amount of motion possessed by the malleus when pressed upon by a fine point. The next step is to ascertain the condition of the guttural portion of the Eustachian tube, to lay open the cartilaginous tube with the scissors, and then to expose the cavity of the osseous portion by means of the cutting forceps. In doing this, the tensor tympani muscle is exposed; its structure should be examined, and if it has not a healthy appearance, portions of it should be submitted to microscopic inspection. The upper wall of the tympanum is next to be cut away by means of the cutting forceps. In doing this, great care must be taken not to disturb or disconnect the malleus and incus, which lie immediately beneath it. After the tympanic cavity has been exposed, the first step is to pull the tensor tympani muscle and ascertain how far it causes a movement of the membrana tympani and ossicles. The incus and stapes are now to be touched with a fine point, so as to ascertain their degree of mobility; the tendon of the stapedius muscle is also to be pressed upon. The condition of the mucous membrane of the tympanum and of the mastoid cells is then to be ascertained, and any peculiarity of the cavity, the existence of bands of adhesion, etc., to be noted. “The most delicate parts of the dissection, viz., that of the internal ear, must now be undertaken. The cavities of the vestibule and cochlea are to be exposed by removing a small portion of the upper wall of each. Before reaching the vestibule, the superior semi-circular canal will be cut through and removed; the membranous canal should be drawn out and inspected. As the cavities of the vestibule and cochlea are laid bare, it is desirable to see that the quantity of perilymph is natural, as well as its color and consistence. The outer surface of the membranous labyrinth having been observed, it should be opened so as to expose the endolymph and otoliths, portions of all which parts should be removed for microscopic inspection. This having been effected, the remaining membranous semi-circular canals are to be exposed, and the connection of the base of the stapes to the fenestra ovalis carefully examined. The last stage of the dissection consists in removing parts of the lamina spiralis, in examining them microscopically, and in exposing from within, by following the course of the scala tympani, the membrane of the fenestra rotunda. “The only part which now remains unexamined is the stapedius muscle; in order to expose it, the course of the aquæductus Fallopii, beginning at the stylo-mastoid foramen, should be followed until the base of the pyramidal eminence containing the muscle is reached.”[1]