of the Mmtbrana Tympani. '3^ 1 



cli tonus with a whittling noifc, and the hair hanging from 

 the temples became agitated by the current of air which ilmed 

 from the ear. To determine this with greater precision, T 

 railed for a lighted candle, which was applied in turn to each 

 ♦jar, and the flame was agitated in a (imilar manner. Struck 

 with the nov< ky of thefe phenomena, I wifhed to have many 

 witnelfes of them, and therefore requeued him, at the con- 

 elufion of the le&ure upon the organ of hearing, to exhibit 

 them to liis fellow ftudents ; with which requeit he was fo> 

 obliging as to complv. 



It was evident from thefe experiments, that the membrana- 

 tvmpani of each ear was incomplete, and that the air iflued 

 from the mouth, by the Euftachian tube, through an open- 

 ing in that membrane, and cleaned by the external meatus. 



To determine the degree in which the membrana tympani 

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

 that the membrane on the left fide Was entirely deftroyed ; 

 fince the probe itruck againfl the petrous portion of the tem- 

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

 palling through a fmall opening; for, after an attentive exa- 

 mination, the fpace ufually occupied by the membrana tvm- 

 pani was found to be an aperture, without one trace of m 

 brane remaining. 



On the right fide, alfo, a probe could be paflTed into the 

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

 the fides of the meatus, fume remains of the circumference 

 of the membrane could be difcovered, with a circular open- 

 ing in its centre, about the fourth of an inch in diameter. 



From fuch a detlruction of this membrane, partial indeed 

 in one ear, but complete in th it might be expected 



that a total annihilation of the powers of the organ would) 

 have followed : but the deafnefs was inconsiderable. This 

 gentleman, if his attention were exerted, was capable, when 

 in company, of hearing whatever was faid in the ulual tone 

 of converfation ; and it is worthy of remark, that he could 

 hear with the left car bctur tl . the right, thou; 



the Kit no traces of the membrana tympani could be per- 

 ttived. 



When attending the anatomical' lectures, ajfo, he could 



hear, 



