43 8 Mr. Cooper's Observations on the 
duced the destruction of the membrane continues, should a 
fungus arise on the periosteum of the tympanum, or exfoliation 
of the bones forming this cavity occur, and more especially should 
the stapes separate, very considerable deafness will be the con- 
sequence. 
When the membrane of one ear only is destroyed, a greater 
degree of deafness takes place in that ear, than would happen 
in either, were the membrane destroyed in both. This, as I 
stated in my former Paper, probably arises from the disuse into 
which the imperfect ear falls, from its being less quick in its 
powers than the other; a conjecture which seems to be verified 
by the following fact. 
Mr. G , a merchant in the city, lost, at an early period 
of life, so great a portion of the membrana tympani of the left 
ear, that no more of it remained than appears in Fig. 3 ; and, 
as he heard somewhat better with his right ear than with his 
left, he was little in the habit of employing the latter, and con- 
sidered himself at length as almost totally deaf in it. Becoming, 
however, in the month of December last, deaf in the right ear, 
and being obliged, in consequence, to employ the other, he 
found that the left ear was by no means deprived of its powers ; 
although he could force air from his mouth through that ear, 
and, if he suddenly thrust his finger into the meatus, the air was 
heard to rush through his nostrils. 
I feel a hope that the foregoing observations will tend to 
something more than merely to gratify curiosity, and will be 
productive, in the end, of lasting benefit ; for they have induced 
me, in one species of deafness, to try the effect of an operation, 
which has, in several instances, proved successful. 
The deafness to which I allude, is that which arises from an 
