38 UNIVERSITY OF MISSOURI STUDIES 



acoustic process; and 2. that it has the power of producing 

 on its own account subjective tones which no study of mere 

 external conditions could ever have revealed to us as a natural 

 consequence of the physical processes we call tones. 



We saw in the preceding paragraph that all the nerve 

 ends between .r„ and .v, received three shocks in the unit of 

 time. A measurement of the distances in 

 A problem for the figure, however, shows that the time 



future solution intervals between these three shocks, al- 



though approximately the same, are not 

 exactly alike (and, moreover, there are differences in this re- 

 spect between the several nerve ends all of which receive three 

 stimulations). Now, it is probable that the particular nervous 

 excitation set up in each ganglion cell by these three stimula- 

 tions of its terminal fibre and thence carried farther to the 

 brain, may be just the same in either case, whether the shocks 

 are received in an exactly regular rhythm or in a slightly irreg- 

 ular succession. It will be one of the problems of the future 

 to decide what is the limit of irregularity which must not be 

 overstepped if the sensation produced is to be the same as that 

 of a regular series of shocks of the same frequency. At pres- 

 ent we have hardly any certain data upon which to found a 

 decision. We must leave this problem open for the present. 

 It would be well, however, to remember that the above graphic 

 representation of the movement of the partition — for simplic- 

 ity's sake — is based on a number of assumptions, and that 

 the actual movement of the partition is doubtless somewhat 

 different from the one which is here under discussion, and 

 which contains probably only the essential features of the 

 actual movement, not all its minor details. It is entirely pos- 

 sible, under these circumstances, that the irregularity in ques- 

 tion is in reality much less considerable than it appears to us 

 now, and what seems to be an important problem, may turn 

 out to be no problem at all. The reason we have for believ- 



