A NEW THEORY OF HEARING. 343 



the organ of Corti and the lower at another point. The 

 cochlear waves due to the higher note besides passing 

 higher up may pass at the exact point where those of the 

 lower note do, but the displacement is too small to bring 

 the tectoria down upon the sensory hairs at that point 

 although the amplification of displacement as the wave 

 passes forwards suffices to produce this effect further on 

 in the cochlea. The lower note on the other hand 

 produces in the upper part of the cochlea a larger dis- 

 placement of the membranes than does the higher tone, 

 but it produces no stimulus because there is no passing of 

 waves in corresponding phases in these upper regions the 

 waves being too long to so pass here ; that is one wave 

 goes up to the helicotrema and travels backwards along 

 the upper (Eeissnerian) membrane out of the upper 

 regions of the cochlea altogether before it meets the next 

 following wave on its way up the basilar. 



Within these or some such limits, therefore, each pure 

 tone will produce a stimulation of the nerve-ends in one 

 region of the organ of Corti and in one region only : and 

 the region stimulated will depend solely upon the pitch 

 of that tone. 



Now suppose the intensity to increase beyond the 

 supposed limit. 



We shall now have to give names to every point in the 

 length of the organ of Corti. The number of points is 

 infinite and there is no difficulty in providing them with 

 an infinite number of easily understood names or numbers. 

 Let 100 be the name or symbol of that point in the length 

 of the organ where one wave in its backward or return 

 journey along the Eeissnerian membrane passes a wave 

 on the basilar separated from the first by an interval of 

 time equal to Tro^h P ai "t of a second. TheD within 

 previous limits of intensity, 100 indicates the point in the 



