NATURAL HISTORY. i03 



f the ear, which is fashioned out in the temporal 

 bone, like a cavern cut into a rock, seems to be fitted 

 for the purposes of echoing sound with the greatest 

 precision. 



One of the most common complaints in o!d age ia 

 deafness; which probably proceeds from the rigidity of 

 the nerves in the labyrinth of the ear. This disorder 

 also proceeds sometimes from a stoppage of the wax, 

 which art may easily remedy. In order to know whe- 

 ther 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 hi* 

 disorder proceeds from an external cause. 



It often happens, that people hear better with the 

 one ear than with the other ; but these have, what 

 musicians call, a bad ear. I have made several expe- 

 riments on persons of this description ; and I have 

 uniformly found, that their defect in judging properly 

 of sounds proceeds from the inequality of their ears, 

 and from their receiving by both at the same time, 

 unequal sensations. In like manner, as such persons 

 hear false, they also, without knowing it, sing false. 

 They also frequently deceive themselves with regard 

 to the side whence the sound comes, generally sup- 

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



Hearing is a much more necessary sense to man 

 than to animals. In these it is only a warning against 

 danger, or an encouragement to mutual assistance. 

 In man, it is the source of most of his pleasures ; and 

 without it the rest of his senses would be of little benefit. 

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

 whole sphere of knowledge must be bounded by sen- 

 sual objects. We have a singular instance of a young 

 man, who, being born deaf, was restored, at the age 



