The former part of this paper may be considered as a continuation of a preceding one by the same author, printed in the last volume of the Philosophical Transactions, and contains ant enumeration of many more facts and circumstances, from which we gather that an aper- ture in the Membrana Tympani does not essentially diminish the power of the ear, and that even a complete destruction of that mem- brane is not followed by total deafness.
The causes by which it may be injured are here fürther inquired into, and are found chiefly to be a suppuration in the Meatus Audi torius, and any kind of external violence; such as blows on the side of the head, the forcible introduction of extraneous substances into the ear, &c.
Mr. Cooper proceeds next to describe the remedy he has, in con- sequence of his repeated observations that an aperture in the Mem- brana Tympani does not injure the ear, thought fit to apply to one particular species of deafness; namely, that which arises from an obstruction in the Eustachian tube. After enumerating the causes which most frequently produce these obstructions, such as colds, which often affect the parts contiguous to the orifice of this tube, ulcers in the throat, extravasation of blood, and uncommon strictures in the tube, the author proceeds to describe his operation, which con sists simply in puncturing the membrane, with very httle pain to the patient, and with instant relief to the disorder.
Several cases are described in which the operation has proved suc- cessful
The criteria are next mentioned by which it may be known whether this tube be closed or open: and lastly, those kinds of deafness are enumerated in which the operation is not likely to produce any salu- tary effect.These are, when the auditory nerve is affected; when there is any alteration in the contents of the labyrinth; and when in general any derangement takes place which does not immediately affect the Eustachian tube.
different Distances, when deprived of the Crystalline Lens. By Everard Home, Esq. F.R.S. Read November 5, 1801
[Phil Trans. 1802, p. 1.]Its object is to state some facts and observations in support of an opinion advanced by the author in a former Lecture, that the ad- justment of the eye to see objects at different distances does not de. pend upon any internal changes in the crystalline lens.
Before he proceeds, Mr. Home pays a due tribute of praise and
