284 THE EAR. 



to such as are disposed to investigate the minute mechanism 

 of an organ, which contributes remarkably to some of our 

 most exquisite and refined enjo^^ments. Though the rapid 

 glance of the eye, and the immense distance to which it 

 enables us to carry our perceptions have given rise to some 

 of our most pleasurable and magnificent sensations, still the 

 sense which we are now considering has contributed most 

 efficiently to the daily happiness of life. It enables us to 

 hold communication with our fellow creatures ; to improve 

 and exalt our understandings by the mutual interchange of 

 ideas ; and thus to increase the circle not only of our physi- 

 cal, but of our moral relations. The charms of eloquence 

 and the pleasure resulting from the concord of sweet sounds 

 are other sources of intellectual enjoyment, which contribute 

 to place this sense among the most delightful as well as the 

 most important we possess. 



The organ of hearing, in its simplest form, consists of the 

 expansion of a nerve, gifted with its peculiar sensitive quali- 

 ties, over the surface of a delicate membrane. In man and 

 the more perfect animals, there is an additional apparatus 

 connected with this, the design of which is to collect and 

 modify those pulses of the air which are finally to be im- 

 pressed on the nervous membrane. In man this apparatus 

 consists of a piece of cartilage, seated externally to the head, 

 which contracts into a tube leading to the internal parts. 

 The bottom of this tube is truncated obliquely, and its aper- 

 ture closed by a firm membrane stretched across it, called 

 the drum of the ear, which separates the external part from 

 the succeeding, or middle portion of the organ. Beyond, or 

 on the opposite side of this membrane, we meet with a small 

 cavity, hollowed out in bone. Of the several openings into 

 it, there is one more particularly demanding attention. It 

 is the internal aperture of a tube, the other extremity of 

 which opens behind and above the palate. By means of this 

 communication, the external air is admitted into the cavity, 

 and equipoises the weignt of the atmosphere on the other 

 side of the membrane. Across the cavity there is extended, 

 though by no means in a straight line, a series of Jittle bones, 

 the exterior one of which is attached to the membrane we 

 have just mentioned, the most internal set being firmly con-* 

 nected with another membrane, which, in conjunction with 

 it, shuts up the entrance to s^ still more deepened cavity, 



