STIMULATION THE SENSES 



in 



of Corti elements appears to be sufficient also, but they are more 

 difficult to estimate. 



So long as a disturbance is sent along a particular nerve fibre, 

 it does not matter whether or not this disturbance corresponds 

 in its form, or in the rate at which separate impulses follow one 

 another, with the sound vibrations in the air. When it reaches 

 a particular region of the brain, we have the sensation of a certain 

 note, in which the separate vibrations are not distinguished. 



wwww 



FIG. 5. Compound Wave Forms resulting from Fusion of a Vibration of a 

 certain rate with one of twice that rate, in two different Phase Relations 

 with each other. 



It should be mentioned that the view according to which the 

 basilar membrane responds to different rates of vibration by 

 resonance is due, in the main, to Helmholtz. Although it is more 

 in agreement with all the facts than other theories, there are some 

 which assert that the basilar membrane vibrates, as a whole, to all 

 notes, the wave form of which is held to be transmitted to the 

 brain in all its detail, so that the analysis is performed there. 



A few words are necessary on the perception of quality in 

 musical sounds. Why is the same note played on the violin and 

 on the flute so different? It is because, in the first case, the 



