200 



OF SENSATION, AND THE ORGANS OF THE SENSES. 

 [Fig. 54. 



The soft parts of the Vestibule taken out of their bony case, so as to show the distribution of the Nerves 

 in the Ampullae; 1, the superior semicircular membranous canal or tube; 2, the external semicircular 

 tube; 3, the inferior semicircular tube; 4, the tube of union of the superior and inferior canals; 5, the 

 sacculus ellipticus; 6, the sacculus sphericus; 7, the portio dura nerve; 8, the anterior fasciculus of the 

 auditory nerve; 9, the nerve to the sacculus sphericus; 10, 10, the nervous fasciculi to the superior and 

 external ampullne; 11, the nerve to the sacculus elliplicus; 12, the posterior fasciculus of the auditory 

 nerve, furnishing 13, the filaments of the sacculus sphericus, and 14, the filaments of the cochlea, cut off.] 



[Fig. 55. 



The Ampulla of the External Semicircular Membranous Canal, showjng the mode of termination of its 

 Nerve.] 



another body of the same pitch is made to sound near it. Thus if two strings 

 of the same length and tension be placed alongside of each other, and one of 

 them be sounded with a violin-bow, the other will be thrown into reciprocal 

 vibration ; or if the same tone be produced near the string in any other man- 

 ner, as by a flute, or a tuning-fork, the same effect will result. 2. Vibrations 

 of resonance are of somewhat the same character ; but they occur when a 

 sounding body is placed in connection with any other, of whi^n'one or more 



