154* Mr. Cooper's Observations on the 



had been injured, I passed a probe into each ear, and found that 

 the membrane on the left side was entirely destroyed ; since 

 the probe struck against the petrous portion of the temporal 

 bone, at the interior part of the tympanum, not by passing 

 through a small opening; for, after an attentive examination, the 

 space usually occupied by the membrana tympani was found- 

 to be an aperture, without one trace of membrane remaining. 



On the right side also, a probe could be passed into the cavity 

 of the tympanum ; but here, by conducting it along the sides of 

 the meatus, some remains of the circumference of the mem- 

 brane could be discovered, with a circular opening in its centre* 

 about the fourth of an inch in diameter. 



From such a destruction of this membrane, partial indeed in 

 one ear, but complete in the other, it might be expected that a 

 total annihilation of the powers of the organ would have fol- 

 lowed: but the deafness was inconsiderable. This gentleman, 

 if his attention were exerted, was capable, when in company, of 

 hearing whatever was said in the usual tone of conversation ; 

 and it is worthy of remark, that he could hear with the left ear 

 better than with the right, though in the left no traces of the 

 membrana tympani could be perceived. 



When attending the anatomical lectures also, he could hear, 

 even at the most distant part of the theatre, every word that was 

 delivered ; though, to avoid the regular and constant exertion 

 which it required, he preferred placing himself near the lec- 

 turer. 



I found, however, that when a note was struck upon the 

 piano forte, he could hear it only at two thirds of the distance 

 at which I could hear it myself; and he informed me, that in 

 a voyage he had made to the East Indies, while others, when 



