ACTION OF THE LABYRINTH DURING HEARING. 



817 



the help of resonators a musical note can be resolved into its fundamental tone and 

 overtones, so the ear is capable of performing such an analysis. The ear resolves 

 the complicated wave-forms of musical tones into their components. These com- 

 ponents it perceives as tones harmonious with each other ; with marked attention 

 each is perceived singly, so that the ear distinguishes as different tone-colours only 

 different combinations of these simple tone-sensations. The resolution of complex 

 vibrations, due to quality, into simple pendulum-like vibrations is a characteristic 

 function of the ear. What apparatus in the ear is capable of doing this 1 If we 

 sing vigorously e.g., the musi- 

 cal vowel A on a definite note, 

 say b i? against the strings of 

 an open pianoforte while the 

 damper is raised, then we cause 

 all those strings, and only those, 

 to vibrate sympathetically, 

 which are contained in the 

 vowel so sung. We must, 

 therefore, assume that an ana- 

 logous sympathetic apparatus 

 occurs in the ear, which is tuned, 

 as it were, for different pitches, 

 and which will vibrate sympa- 

 thetically like the strings of a 

 pianoforte. "If we could so 

 connect every string of a piano 

 with a nerve-fibre that the nerve- 

 fibre would be excited and per- 

 ceived as often as the string 

 vibrated, then, as is ac- 

 tually the case in the 

 ear, every musical note 

 which affected the in- 

 strument would excite 

 a series of sensations 

 exactly corresponding to 

 the pendulum-like vi- 

 brations into which the 

 original movements of 

 the air can be resolved ; 

 and thus the existence 



Fig. 600. 

 Koenig's apparatus for analysing a compound tone with the 

 fundamental tone ut 2 . 



of each individual overtone would be exactly perceived, as is actually the case with 

 the ear. The perception of tones of different pitch, would under these circum- 

 stances depend upon different nerve-fibres, and hence would occur quite inde- 

 pendently of each other. Microscopic investigation shows that there are somewhat 

 similar structures in the ear. The free ends of all the nerve-fibres are connected 

 with small elastic particles which we must assume are set into sympathetic vibra- 

 tion by the sound-waves " (v. Helmholtz). 



Resolution by the Cochlea, Formerly v. Holmholtz considered the rods of Corti 

 to be the apparatus that vibrated and stimulated the terminations of the nerves. 

 But, as birds and amphibians, which certainly can distinguish musical notes, have 

 no rods (Hasse), the stretched radial fibres of the membrana basilaris, on which the 

 organ of Corti is placed, and which are shortest in the first turn of the cochlea, 

 becoming longer towards the apex of the cochlea, are now regarded as the vibrating 



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