290 AVE/^S. [Vol. VI. 



the hairs cannot have the same dimensions — length,^ the same 

 relations of reduction in size to the length of the filament and 

 identical basal relations — it necessarily follows that the hairs, 

 like the stalks of grass, will be affected differently by the same 

 vibrational energy, and that consequently many, or perhaps under 

 powerful stimuli all, of the hairs will be affected sequentially by 

 the same impulse, though the stimulation of the nerve ends of 

 different cells, and perhaps of any single cell, would necessarily 

 be different ; for our argument it matters not whether the stim- 

 ulus be a simple, powerful pendular vibration or a composition 

 of pendular vibrations. In the former case, the simple pendular 

 vibration would cause a simple undulation to flow over the sur- 

 face of the hair band of the cochlea with a regular, even flow, so 

 that the single hairs in transverse groups would be successively 

 affected, and thereby produce a continuous flow of stimulation 

 toward the brain centres, giving rise to concomitant stimula- 

 tions of the central end organs. 



The hairs, however, would not act or react all alike ; for the 

 shorter ones, being struck down by the wave motion, would 

 react more quickly than the longer ones, and would conse- 

 quently not send the same kind of impulse through their end 

 cell, and hence not produce the same nervous disturbance or 

 irritation in the brain as would be produced by the long hairs. 

 This process would be repeated for every segment of the coch- 

 lear organ. In the latter case, the hairs would send stimuli of 

 still greater differences, owing to the increased inequality of 

 motion transmitted to the individual hairs. 



Since we have found that the cochlear organ is divisible into 

 a series of sense-organ units, we are compelled by all organic 

 analogies to assume that there is at least some small physiologi- 

 cal differentiation among the organs. 



At any rate, beginning at the base of the cochlear tube and 

 progressing toward the summit, we would have a sequence of 

 stimuli sent into the brain from the sense organ, beginning at 

 No. I and progressing to No. 125 (taking a medium number for 

 convenience' sake) ; and since the nerves of the sense organ, 

 from No. i to No. 125, are successively longer, and since the 



1 We know that in different parts of the cochlea they have different lengths, but 

 it is also probable that the hairs borne by a single cell vary in size and length (com- 

 pare Fig. 9, Plate VIII). 



