294 



COMPARATIVE PHYSIOLOGY OF THE BRAIN 



theory can be applied to the other sense-organs. But 

 it is certain that if we wish to make any progress in 

 this direction we must follow the lead of Mach and 

 Hering, and must cease to consider the so-called 

 law of the specific energy of the sense-organs as the 

 terminus of our investigation of the processes of 

 sensation. 



2. If we wish to find out the dynamics of associa- 

 tion we must study the effects which simultaneous 

 processes have upon each other. Let us consider 

 periodic and aperiodic processes. 



If we turn a wheel with one hand without thinking 

 of the manner or velocity of the rotation, and at the 

 same time repeat a poem to ourselves without moving 

 the lips, the number of the revolutions shows a simple 

 numerical relation to the number of the arses of the 

 verses. In German, where the arsis is pronounced 

 with greater emphasis than the thesis, the number of 

 the rotations of the wheel generally equals the num- 

 ber of the arses. Briicke first called attention to this 

 relation. Thirteen years ago I made a large number 

 of experiments (not published) concerning this sub- 

 ject that yielded the same result. But I found, fur- 

 ther, that if one intentionally turns the wheel rapidly 

 and recites slowly, the number of rotations is a simple 

 multiple of the arses. Two, three, or even more re- 

 volutions are made in the interval of one arsis. If one 

 recites very rapidly and turns the wheel very slowly, 

 the number of the arses becomes a simple multiple of 

 the number of revolutions. In the latter case, the 



