152 Irving Hardesty 



Eutherford first advocated that all the hairs of the hair cells vibrate 

 equally to every note and that the nerve impulses thus aroused are mere 

 vibrations similar in frequency, amplitude (intensity), and character 

 (quality) to the soimd vibrations, and that, therefore, sound analysis is 

 wholly cerebral. 



Waller and Meyer assumed that the transformed sound vibrations in 

 the endolymph act upon the basilar membrane as a whole, repeating the 

 vibrations of the tympanic membrane. Meyer supposes that each wave, 

 as it passes up the scala vestibuli, presses the basilar membrane down- 

 wards and does this just in the proportion in which amplitude of the 

 wave is not decreased by the resistance it meets in passing upward 

 toward the apex. Thus each wave will produce irritation of a certain 

 number of hairs and the intensity of the irritation will diminish as the 

 amplitude of vibration is diminished by resistance; and therefore a 

 wave of greater amplitude will involve a greater extent of the basilar 

 membrane, and of auditory hairs, than a wave of lesser amplitude. 

 Certain waves, sooner than others, in passing up the scala will become 

 too faint to sufficiently press down the basilar membrane. According to ^ 

 this view, pitch depends upon vibration frequency or the number of 

 stimuli per second, while intensity depends upon the total number of 

 nerve endings irritated. It allows a certain amount of analysis in the 

 cochlea. 



The telephone theory differs from that of Helmholtz in that it 

 assumes that the basilar membrane, instead of certain of its fibers 

 vibrating in sympathy with given notes, vibrates as a whole to every 

 note in so far as the original amplitude of the wave and resistance to 

 propagation will allow, and that the auditory nerve fibers transmit to 

 the brain stimuli of frequencies and intensities of the note or notes 

 concerned. The resonance theory supposes analysis of sound by the 

 cochlea; while the telephone theory supposes distinctions of sound, 

 perception of tone, etc., to be accomplished by the brain, made possible 

 of course by the varying quality of the stimuli in the peripheral organ, 

 the cochlea. The resonance theory of necessity requires that each fiber 

 of the basilar membrane and each arch, or pair of rods, of the organ of 

 Corti be able to vibrate or move upward and downward independently. 



Numerous objections to the resonance theory have been made, both 

 physiological and anatomical. Of the physiological objections, two may 

 be cited as examples of those the obviation of which has been recently 

 undertaken bv adherents of the resonance theory. 



