50 NATURAL THEOLOGY. 



with the external air. In one word, it exactly 

 answers the purpose of the hole in a drum. 



The membrana tympani itself, likewise, deserves 

 all the examination which can be made of it. It 

 is not found in the ears of fish ; which furnishes 

 an additional proof of what indeed is indicated by 

 every thing about it, that it is appropriated to the 

 action of air, or of an elastic medium. It bears an 

 obvious resemblance to the pelt or head of a drum. 



[This figure represents the membrane of the tj-mpanum of a 

 larger size than natural. It is represented as tucked in by the 

 handle of the malleus. The description of Sir Everard Home, re- 

 ferred to in the text, is altogether fanciful. There is no proof that 

 these fibres are muscular : they are drawn tight by the small mus- 

 cle attached to the matteus called tensor tympani; and it would ap- 

 pear that these cords are necessary to produce that variety of mo- 

 tion in the membrane suited to all the variety of sounds which are 

 conveyed through it to the seat of the sense. Sir Everard played 

 to the elephant on the piano-forte. That the animal took some 

 notice of the extraordinary sound cannot surprise us; but the in- 

 ferences drawn by Sir Everard were equally ingenious and ground- 

 less. He supposed that the musical ear was owing to the mem- 

 brane of the tympanum.] 



