AUDITORY APPARATUS IN MAN. 183 



siastic feelings in one, are heard and seen by another with 

 no sort of effect. It is true, however, that there is a natu- 

 ral difference in these respects, and especially with regard 

 to music, there being some uneducated ears which are able 

 to appreciate the finest passages in a piece, though they 

 never had heard good music before. This, however, is 

 seldom the case with respect to painting, deep impressions 

 and good judgment being nearly in every case the result 

 of education. 



569. In treating of hearing, we shall, as we have done 

 with respect to vision, begin with that structure which is 

 most highly developed and best understood, the human ear. 



DESCRIPTION OF THE AUDITORY APPARATUS IN MAN. 



570. The best summary on this subject we have seen, 

 for the design of this work, is that of Dr. Roget, in his 

 " Bridgewater Treatise, on Animal and Vegetable Physi- 

 ology." This, therefore, will form the basis of the follow- 

 ing treatise. 



571. That part of the organ of hearing, which, above 

 all others, is essential, is the acoustic or auditory nerve, 

 of which the fibres are expanded, and spread over the 

 surface of a fine membrane, placed in a situation adapted 

 to receive the full impression of the sonorous undulations 

 which are conveyed to them. This membrane, then, with 

 its nervous filaments, which is situated within the labyrinth, 

 may be regarded as the immediate organ of this sense ; all 

 the other parts constituting merely an accessory apparatus, 

 designed to collect and condense the vibrations of the sur- 

 rounding medium, and to direct their concentrated action 

 on the auditory membrane. 



572. The principal parts of this complicated organ are 

 exhibited in Fig. 114, as they exist in man, in their rela- 

 tive and of their natural sizes ; these parts will, therefore, 

 afford a scale of real dimensions of those portions which 

 will hereafter be explained by magnified views. 



What is it in musical tones that give pleasure ? What is said of the ear * 

 Can some enjoy good music without education ? 



