500 



HEARING, VOICE AND SPEECH 



hair cells, 12,000 outer hair cells (in four rows), and 24,000 fibers in the 

 basilar membrane. 



We can only conjecture which of these structures are the true resonators. 

 Originally, Helmholtz ascribed this function to the pillars of Corti; later, 



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however, he gave up this view because it was found that birds and reptiles have 

 no such pillars in their auditory organ. After Hensen had established the 

 fact that the basilar membrane varies in width in different parts of the cochlea, 



