42 HISTORY OF 



subject), is beaten against the tympanum or drum 

 of the ear, which moves four little bones joined 

 thereto ; and these move and agitate the internal 

 air which lies on the other side ; and lastly, this 

 air strikes and affects the auditory nerves, which 

 carry the sound to the brain." 



One of the most common disorders in old age 

 is deafness ; which probably proceeds from the 

 rigidity of the nerves in the labyrinth of the ear. 

 This disorder also, sometimes, proceeds from a 

 stoppage of the wax, which art may easily reme- 

 dy. In order to know whether the defect be an 

 internal or an external one, let the deaf person 

 put a repeating watch into his mouth, and if he 

 hears it strike, he may be assured that his disorder 

 proceeds from an external cause, and is in some 

 measure curable ; "for there is a passage from 

 the ears into the mouth, by what anatomists call 

 the eustachian tube ; and by this passage people 

 often hear sounds, when they are utterly without 

 hearing through the larger channel : and this also 

 is the reason that we often see persons who listen 

 with great attention, hearken with their mouths 

 open, in order to catch all the sound at every 

 aperture." 



It often happens, that persons hear differently 

 with one ear from the other ; and it is generally 

 found that these have what is called by musicians 

 a bad ear. M. Buffon, who has made many trials 

 upon persons of this kind, always found, that their 

 defect in judging properly of sounds proceeded 

 from the inequality of their ears ; and receiving 

 by both, at the same time, unequal sensations, 



