No. I.] THE VERTEBRATE EAR. 29 1 



time of propagation of the stimulus, from No. i to No. 125, 

 increases the difference of time of the reception of the stimula- 

 tions in the central end organ, we recognize that there are two 

 sources of variation of the stimulative process of the external or 

 surface organs which must make a great impression on the cen- 

 tral end organs, and lend themselves to the formation of suitable 

 associative and co-ordinative processes or the processes of judg- 

 ment, especially to the recognition of time differences between 

 the stimuli applied.^ It follows from this that one and the same 

 pendular vibration will send a series of stimuli to the brain, and 

 that the stimuli from one source are not necessarily of the same 

 kind ; but in all cases the sequence will be the same and the 

 variations the same for any given undulation or series of undu- 

 lations. 



As I have already shown, the hairs end not in identical man- 

 ner on the top of each cell, and as physical measurements, which 

 I have carried out with all the care possible for the purpose of 

 excluding sources of error, proves the hairs are not of the same 

 size at their basal ends, nor have they the same lineal dimen- 

 sions. The end cells vary somewhat in size, length, and in the 

 relative position of the nucleus and the manner in which the 

 nerve fibre enters the cell. 



Now, these with other frequent modifications of the typical 

 hair cells, or, better expressed, these ever-increasing individuali- 

 ties of the structural relation of the cells comprising the hair 

 band, necessitate the conclusion that each hair cell is somewhat 

 individual in its physiological processes. For example, a cell 

 with long capillo-nuclear filaments will be affected most power- 

 fully by wave motions transmitted to them in time and form, 

 most easily propagated through their substance, and this selection 

 process, having been already applied by the hair itself to the 

 undulation that swept down the hair plate, results in a still finer 

 physical selection, which must still further be modified as it is 

 transferred from the capillo-nuclear filaments to the nucleus, 

 and from the nucleus transmitted through the nucleo-neural fila- 

 ment to the extra-cellular nerve. The modification of the stim- 

 ulus, during its passage from the nerve through the cochlear 



1 The most essential quality of music rests on the perception of time differences 

 according to some accepted law, to the recognition of which and acquiescence in, the 

 individual lends himself or is structurally inclined. 



