HEARING. 



35 



The windings and other inequalities of the outer 

 ear meet in the narrowest part of the entrance, and 

 the windings thus united take the form of a tube, 

 which enters the bone of the temple, and is continued 

 through it, till it reach the part called the drum 

 (tympanum'). " Infants," says Smellie, " hear bluntly, 

 because the bones of their ears are soft and carti- 

 laginous ; and, of course, the tremulations excited 

 in them, by the motions of the air, are comparatively 

 weak. Young children, accordingly, are extremely 

 fond of noise : it rouses their attention, and conveys 

 to them the agreeable sensation of sound ; but feeble 

 sounds are not perceived, which gives infants, like 

 deaf persons, the appearance of inattention, or rather 

 of stupidity*" 



The Tympanum and Bones of the Ear. 



The skin which lines the entrance tube of the ear 

 (meatus externus) is extremely thin and delicate, and 

 is reflected over the drum so as to cover it. This 

 tube is oblique and winding, to prevent (it may be) 

 the sound from being reflected from the drum into 

 the air again without producing the sensation of 

 hearing, which would, to a certain extent, be the 

 consequence were the tube straight. 



* Philosophy of Natural History, i. 268, 8vo. 



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