ABSTRACTS 



OF 



THE PAPERS PRINTED IN 



THE PHILOSOPHICAL TRANSACTIONS. 



The Croonian Lecture. On the Structure and Uses of the Membrana 

 Tympani of the Ear. By Everard Home, Esq. F.R.S. Read Nov 7 

 1799. [Phil. Trans. 1800, p. 1.] 



JL HE part of the ear which was the subject of the present lecture, 

 has always been considered as a common membrane, which, being 

 stretched or relaxed by means of muscles belonging to the malleus, 

 became fitted in its various degrees of tension to convey the immense 

 variety of external sounds to the internal organ. 



Though this description have been generally adopted, yet it will 

 appear upon further inquiry that, owing no doubt in a great measure 

 to the extreme minuteness of the part, the structure and some of the 

 properties of this membrane had not as yet been properly investigated. 

 And the discovery here announced is brought forward with the greater 

 propriety on this occasion, as it affords a new instance of the appli- 

 cation of muscular action, which may ultimately account for certain 

 phenomena in the sense of hearing in a more satisfactory manner 

 than has hitherto been proposed. 



This discovery we owe in some measure to the opportunity Mr. 

 Home had to dissect the ear of an elephant, where the parts are so 

 much larger even than they ought to be in proportion to the size of 

 the animal, that the structure of this membrane, which is usually de- 

 nominated the Drum of the Ear, becomes obvious even to the naked 

 eye. On close examination it was found, that instead of being an 

 uniform coat or skin, a great number of muscular fibres, which seem 

 incorporated in it, pass along its texture in a radiated manner from 

 the rim which surrounds it, towards the handle of the malleus, with 

 which the central part of the membrane is firmly connected. 



Having thus been put upon the scent, the membrane in the human 

 ear was carefully separated from its contiguous parts, and being 

 viewed in a microscope, magnifying 23 times, exhibited the same 



