106 ON THE MEMBRANA TYMPANI OF THE EAR. 



The caufes of The caufes of deafnefs are extremely numerous ; and many 

 merous 5 "nd""" °^ ^°^ e wmcn affect only the meatus auditorius, the mem- 

 many cafes may brana tympani, the cavity of the tympanum, and the Eufta- 

 £ r ^ cd by chian tube, admit of relief from furgery. 

 Nervous deaf- But there is one fpecies, in which it would be abfurd to 

 ncf * # expect this from any operation upon the membrana tympani. 



This occurs more frequently than any other, happening gene- 

 rally in old perfons ; but fometimes, in the delicate and irri- 

 table, in the earlier flages of life. Anxiety and diftrefs of 

 mind have been known to produce it. Its approach is gene- 

 Tally gradual : the perfon hears better at one time than at 

 another; a cloudy day, a warm room, agitated fpirits, or the 

 operation of fear, will produce a confiderable diminution in 

 the powers of the organ. In the open air the hearing is bet- 

 ter than in a confined fituation ; in a noify, than in a quiet 

 fooiety ; in a coach when it is in motion, than when it is flill. 

 A pulfation is often felt in the ear ; a noife, refembling fome- 

 times the roaring of the fea, and at others the ringing of 

 diftant bells, is heard. This deafnefs generally begins with a 

 diminifhed fecretion of the wax of the ear, which the patient 

 attributes to fome unufual expofure of the head to cold ; and 

 May be cured in this continues as long as the difeafe remains. It may be 

 the commence- cur ed in the commencement by the application of fuch ftimu- 

 lants. lants, as are capable of exciting a difcharge from the ceru- 



minous glands ; for which purpofe they fhould be introduced 

 into the meatus. But if thefe be ufed fo as to irritate, without 

 exciting a difcharge, they are. rather prejudicial than otherwife. 

 In cafes of this kind the operation has afforded no farther 

 relief than dimini(hing the noife in the head. 

 Deafnefs from Another caufe of deafnefs is probably irremediable. This 



fLfrfubftancf is the g eneration of a folid fobftance in the labyrinth of the 

 in the labyrinth, ear, inftead of the water with which it is naturally filled. 

 Mr. Cline, differing the head of a young man born deaf, 

 and confequently dumb, found all the parts of the organs of 

 hearing perfectly formed, but the veitibule, cochlea, and 

 femicircular canals, were filled with a fubftance of the con- 

 fidence of eheefe. 



Thefe inftances of deafnefs Mr. Cooper thought it right to 

 describe, becaufe they are liable to be confounded with that 

 which arifes from a clofed Euftachian tube. 



4 "EXPLANATION 



