322 THE BODY AT WORK 



ment in the past used to run somewhat thus : " I decide to act 

 or to abstain from action. The nerve-cell is the mechanism by 

 means of which I decide. Therefore the nerve-cell decides.' 

 (In the past a distinction was drawn between the cell-body and 

 its processes, but that, we now see, was absurd.) It is very 

 difficult to relinquish completely this attitude of mind. I 

 feel, I remember, I will. There must be a something which 

 feels, remembers, wills. But a physiologist finds in the nervous 

 system no evidence of a capacity for any function other than 

 that of conduction, with adjustment of the force of current. 

 He can no more discover feeling, memory, or will in a chain of 

 neurones than he can find music in a violin. He hears the 

 strings singing in the breeze. He can twang them with an 

 electric shock. But he has no vision of ghostly performers, 

 no glimpse of the conductor's baton. Yet he knows, as every 

 sane man knows, that the neurones are the instruments played 

 in the orchestra of mind. He knows that, while all are sound- 

 ing, some are muted, in order that the others may produce a 

 dominant effect. He knows, too, whenever he decides to con- 

 tinue writing or to close his notebook, that the conductor is 

 raising the baton or allowing it to sink by his side. 



A neurone or nerve-cell is a transmitting link. It is scarce 

 a thing to wonder at that physiologists, having wrestled 

 successfully with the superstition of the " pontifical nerve- 

 cell," are unwilling to reinstate it even as doorkeeper in a free 

 church. It may be that it exercises some discretion in ad- 

 mitting impulses, but until its authority as a guardian of the 

 path which stretches behind it has been established, it is better 

 to regard it merely as a door which swings open whenever 

 pressed with sufficient force. 



Is it possible to classify neurones according to their function ? 

 They can be classified according to size, and, with some degree of 

 completeness, according to form. But if, as we believe to be 

 the case, size and form are governed by purely physical re- 

 quirements, the divisions into which the cells fall have no 

 physiological significance. The motor cells of the spinal cord 

 and axis of the brain are large and irregular in shape. Their 

 dimensions are clearly dependent upon the size, thickness 

 rather than length, of the nerve-fibres which are drawn out 

 from them. They discharge impulses to groups of voluntary 



