ANIMALS. 22i 



The internal cavity of the ear seems to be fitted up for the purpose 

 of echoing sound with the greatest precision. This part is fashioned 

 out in the temporal bone, like a cavern cut into a rock. " In this the 

 sound is repeated and articulated; and, as some anatomists tell us, 

 (for we have as yet but very little knowledge on this subject,) is 

 hnaten 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 remedy. 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 tha 

 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 mu- 

 sicians, a bad ear. Mr. 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 

 oy both at the same time unequal sensations, they form an unjust idea. 

 In this manner, as those people hear falsely, they also, without know- 

 ing it, sing false. Those persons also frequently deceive themselves 

 with regard to the side from whence the sound comes, generally sup- 

 posing the noise to come on the part of the best ear. 



Such as are hard of hearing find the same advantage in the trumpet 

 made for this purpose, that short-sighted persons do from glasses. 

 These trumpets might be easily improved, so as to increase sounds, 

 in the same manner that the telescope does objects ; however, they 

 could be used to advantage only in a place of solitude and stillness, 

 as the neighbouring sounds would mix with the more distant, and the 

 whole would produce in the ear nothing but tumult and confusion. 



Hearing is a much more necessary sense to man than to animals. 

 With these it is only a warning against danger, or an encouragement 

 to mutual assistance. In man, it is the source of most of his plea 

 sures, and without which the rest of his senses would be of little be- 

 nefit. A man born deaf, must necessarily be dumb ; and his whole 

 sphere of knowledge must be bounded only by sensual objects. We .< 

 have an instance of a young man, who being born deaf, was restored 

 at the age of twenty-four to perfect hearing : the account is given in 

 the Memoires of the Academy of Sciences, 1703, page 18. 



A young man of the town of Chartres, between -the age of twenty 

 three and twenty-four, the sen of a tradesman, and deaf and dum 

 from his birth, began to speaV. all of a sudden, to the great astonish 



VOL. i. P 



