ORGAN OF HEARING. 



175 



Those of audi- View of the Left Ear in its Natural 



logical information. Happily, it is not Fig. 63. 



necessary for our purpose to go so minutely 

 into the description of the organ of hear- 

 ing. According to the plan hitherto pur- 

 sued, allusion will be made to those portions 

 only that concern the physiological in- 

 quirer. 



In the ear, as well as in the eye, we have 

 the distinction between the physical and 

 nervous portions of the organ more clearly 

 exhibited than in the skin, mouth, or nose. 

 The nervous portion is situate deeply 

 within the organ; and the parts between 

 it and the exterior act physically on so- 

 norous vibrations, in the case of the ear ; 

 and on light, in that of the eye. 



The organs of the senses hitherto con- 

 sidered are symmetrical. 



tion are two in number, distinct but bar- V2 Origin and termina t ion of the 

 monious, and situate at the sides of the |L elix - 3 Antheiix. 4 Antitragus. 5. 



, , . ' c -i 11 Tragus. 6 Lobus of the external ear. 



nead, in a part ot the temporal bone, ge- 7. Points to the scapha, and is_on the 

 nerally called, from its hardness, pars pe- 9Meau! 

 trosa, and by the 



French and German Fig. 64. 



anatomists regarded 

 as a distinct bone, 

 under similar appella- 

 tions Le Hocher^aud 

 F e 1 s e n b e i n, ( " rock- 

 bone.") This bone is 

 seated at the base of 

 the skull, so that the 

 internal parts of the 

 auditory organ are 

 deeply and securely 

 lodged. 



For facility of de- 

 scription, the ear may 

 be. divided into three 

 portions: 1. Exter- 

 nal ear or that exte- 

 rior to the membrana 



tympani * 2. Middle General View of the External, Middle, and Internal Ear, as seen 



in a Prepared Section. (From Scarpa.) 



ear the space con- 



11 ,1 a. The auditory canal, b. The tympanum or middle ear. e. Eus- 



)6tWeen tne tachian tube, leading to the pharynx, d. Cochlea; ande. Semicir- 



momVv?rQ f Tr-mi-var*! cular canals and vestibule, seen on their exterior, as brought into 



lid, tympani yiew fay dissecting . away the surrounding petrous bone. The styloid 



and internal ear; and process projects below ; and the inner surface of the carotid canal is 



rjll . , seen above the Eustachian tube. 



3. The internal ear 



in which the auditory nerve is distributed. 



1. External Ear. This portion of the auditory apparatus is com- 



