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VIII. Observations on the Effects which take place from the De- 

 struction of the Membrana Tympani of the Ear. By Mr. Astley 

 Cooper. In a Letter to Everard Home, Esq. F. R. S. by 

 whom some Remarks are added. 



Read February 6, 1800. 



DEAR SIR, 



At the time you were engaged in the investigation of the 

 structure and uses of the membrana tympani, you mentioned 

 a wish to ascertain the effect a rupture of that membrane would 

 have upon hearing. I now send you some observations on that 

 subject, which, if you think them of sufficient importance, you 

 will do me the honour of presenting to the Royal Society. 



I am, &c. 



ASTLEY COOPER, 



Anatomists have endeavoured to ascertain, by experiments 

 on quadrupeds, the loss of power which the organ of hearing 

 would sustain by perforating the membrana tympani : dogs 

 have been made the subject of these trials ; but the results have 

 been neither clear nor satisfactory, and they accord but little 

 with the phaenomena I am about to relate. 



Mr. Cheselden had conceived the design of making the 

 human organ itself the subject of direct experiment; and a con- 



