168 Irving Hardesty 



out by the endolymph and resistance of the walls, and not absorbed in 

 overcoming the viscosity and bulk of the membrane itself. The waves 

 of lowest frequency, or greatest length, may produce corresponding 

 undulations in the entire membrane; waves of the highest frequency 

 may produce in the thinner, and therefore most flexible, end of the mem- 

 brane alone corresponding undulations of sufficient excursions for the 

 necessary impingement upon the auditory hairs. Undulations of high 

 frequency would result in a greater number of impingements per unit 

 of length of the organ of Corti than would waves of low frequency, and 

 thus both the nature and the locality of such stimulation would be dif- 

 ferent. Waves of higher amplitude, or intensity, would produce im- 

 pingements of greater intensity and thus give sensations interpreted in 

 degrees of intensity. 



Functioning in this way, the peripheral organ of the apparatus is 

 functionally as well as morphologically comparable to the so-called 

 otolithic organs, the eristse and maculae acusticge. And, further, it is 

 comparable with the other organs of special sense. The varieties of 

 optic sensations, for example, depend upon the intensity and quality of 

 the stimuli, that is, upon the number and variety of waves of light 

 impinging upon a unit area of the retina. The various sensations 

 obtained by touch depend upon the number, intensity and quality of 

 the stimuli applied to the skin. Differences in quality of stimuli at 

 the periphery are perceived and interpreted as differences by the central 

 nervous organ, A number of stimuli applied to a unit area of the skin 

 gives rise, within the possibilities of skin-innervation, to a different 

 sensation or interpretation than does a single stimulus applied to that 

 area. The same stimuli applied with different intensity give rise to 

 interpretations of different intensity. So, in general, for taste and 

 smell, all being dependent upon contact, whether the energy applied be 

 simply mechanical or more strictly chemical. 



In the auditory organ the stimuli arousing the sensations are thought 

 to be mechanical. The greater numbers of stimuli applied to unit areas 

 of the organ of Corti result from waves of high frequency and give rise 

 to a sensation interpreted and named by the central nervous organ as 

 high pitch. It happens that the region of the cochlea anatomically 

 adapted for mediating sensations of highest pitch is its basal coil. 

 Conversely, smaller numbers of stimuli applied to the unit area are inter- 

 preted as low pitch, the stimuli from waves of the lowest frequency being 

 distributed most sparingly, but throughout the extent of the cochlea, 



