Destruction of the Membrana Tympani. 157 



to raise the ear, or to draw it backwards, he was capable of 

 moving it in either direction. 



This case is not the only one of this description which has 

 come under my observation ; for another gentleman, Mr. A — , 

 applied to me under a similar complaint, (but in one ear only,) 

 proceeding from suppuration, and producing the same effects. 

 This gentleman has the same power of forcing air through the 

 imperfect ear ; suffers equally from bathing, if the meatus audi- 

 torius be unprotected; and feels, even from exposure to a stream 

 of cold air, very considerable pain. The only difference I could 

 observe was, that in Mr. A's case, the defect of hearing in the 

 diseased organ was somewhat greater than in the former ; for 

 though, when his sound ear was closed, he could hear what was 

 said in a common tone of voice, yet he could not distinguish 

 the notes of a piano forte at the same distance : a difference 

 which might have in part arisen from the confused noise which 

 is always produced by closing the sound ear ; or because, as he 

 heard well on one side, the imperfect ear had remained unem- 

 ployed, and consequently had been enfeebled by disuse. 



From these observations it seems evidently to follow, that 

 the loss of the membrana tympani in both ears, far from pro- 

 ducing total deafness, occasions only a slight diminution of the 

 powers of hearing. 



Anatomists who have destroyed this membrane in dogs, have 

 asserted, that at first the effect on the sense of hearing was 

 trivial ; but that, after the lapse of a few months, a total deafness 

 ensued. Baron Haller also has said, that if the membrane of 

 the tympanum be broken, the person becomes at first hard of 

 hearing, and afterwards perfectly deaf. But, in these instances, 

 the destruction must have extended further than the membrana 



