14 Foster, Physical Basis of Psychical Events. 



play upon it, though it is unable to carry out the behests 

 of those influences. 



Putting these various things together we are led to the 

 conclusion that quite apart from the grosser changes which 

 we call a nervous impulse, and which are signalled by an 

 electric change, by the current of action, there must be 

 passing to and fro between the several parts of the neurone, 

 between perikaj;yon and the farthest point of axon or of 

 dendrite, influences, actions, currents, call them what you 

 will, which are signalled by no appreciable electric change, 

 and of which we have at present no direct signs, no 

 indications beyond the phenomena on which I have just 

 dwelt. 



The perikaryon seems to be the chief laboratory. It 

 is here that we find evidence of obvious chemical changes, 

 and especially of changes connected with activity. But 

 I venture to think it would be a mistake to infer, as some 

 seem inclined to do, that these metabolic events of the 

 perikaryon, because they make themselves visible there 

 and there only, produce their effects there only. One at 

 times meets with statements which seem to assume that 

 the perikaryon, that part of the nerve unit which is often 

 called the nerve cell as distinguished from the other parts 

 which are called nerve fibres, is alone the seat of the 

 setting free of energy. The facts, however, of which I 

 have been speaking, point to the conclusion that the 

 good of what is done in the perikaryon is, in some 

 way or other, shared by the whole unit. It may be 

 beyond our present knowledge to frame any hypothesis 

 as to how the chemical labours of the perikaryon are 

 made available for the distant parts of axon. As I 

 have just said, we have evidence that the nucleus is 

 in some way or other in touch with every part of the 

 axon along its whole length, but we are at present in 

 ignorance as to the exact nature of that touch ; we do not 



