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disturbance is to be looked for in an alteration of 

 the condition of some other tissue, most commonly 

 muscular tissue, the contractions of which are excited 

 and controlled by these disturbances. 



When a fuse is ignited there is one path, and only 

 one, along which the energy can be liberated ; but in 

 a complex nervous system the possible paths of dis- 

 charge are innumerable, and the actual path depends 

 on the particular state of the unstable equilibrium of 

 the organism at the moment. It would appear that, 

 whatever be the path taken, the discharge of energy 

 along it makes a more or less permanent alteration in 

 the condition of the nervous tissue along this path in 

 such sense that it becomes easier for subsequent 

 discharges to pass thereby than to take new direc- 

 tions. Thus it comes that whenever energy is 

 liberated at any point along an established track, 

 some part at least of that energy traverses the track, 

 and more or less strongly reinstates the feeling which 

 was the sensory aspect of the earlier discharge along 

 the same track. When the reinstated feeling emerges 

 into consciousness it is called a reminiscence ; but 

 evidently the same process may go on without this 

 emergence, because the same repetition of disturb- 

 ances along previous tracks produces habits which 

 assert themselves without our consciousness. In 

 view of this, that which I have called the immediate 

 sensation can no longer be looked upon as an isolated 

 unit ; it is a disturbance of equilibrium, which at any 



