and on the probable Nature of the Nerve Current. 177 
mate arrangement from other nerve organs in which electricity is 
not set free, render it probable, as it seems to me, that the current 
transmitted by the axis cylinder is ordinary electricity, and that all 
the effects produced upon other tissues depend upon the transmission 
through nerve fibres of currents of electricity varying in intensity. 
But what determines the particular course the electrical current 
shall take, — which fibres shall he traversed by a strong current and 
which by a weak one, — how the intensity of the current varies at 
different times, and is momentarily increased or reduced by the 
influence of the will, — are questions quite apart from the con- 
sideration of the nature of tho current itself. But if we can 
determine the probable nature of the nerve current, or even show 
that there is great probability of it being determined, one very 
important step towards the solution of much higher physiological 
problems will be gained. 
Of the Nerve Current. 
The general opinion, however, of physiologists, as already 
stated, seems to he that the nerve current is some mode of force, 
perhaps correlated with heat, electricity, &c., hut not exactly 
identical with any form or mode of energy known or of which we 
have as yet any experience. The arguments upon which this view 
is founded appear, however, to me very inconclusive. Much of the 
evidence we possess unquestionably favours the view that the nerve 
current is electricity, for many, indeed most, of the phenomena 
familiar to us may be explained upon this view. Lastly, some 
physiologists have sought to account for the wonderful phenomena 
of the nervous system by supposing that some force or power of a 
peculiar and exceptional kind is at work in nerve systems only. 
I shall endeavour to show that if electricity could be made to 
travel in different directions, and the currents combined in various 
ways and made to traverse series of conducting cords very specially 
arranged, according to design, the phenomena of nervous action 
might be accounted for without resorting to the hypothesis of the 
existence of a peculiar power, or of some new mode or form of force 
not yet discovered.* It is at least not improbable that the varying 
effects noticed in connection with the nervous system may be 
determined by alterations in the intensity of the current, and in 
the conducting properties of the fibres, instead of being due to the 
* Physicists and chemists see no difficulty whatever in assuming the existence 
of many modes of force of which they can form no conception, and think it very 
satisfactory to refer phenomena which they cannot understand to some at present 
undiscovered form or mode of ordinary motion ; but if anyone attributes these 
same phenomena to the influence of some equally undiscovered form of force having 
no connection whatever with primary energy or motion, he is ridiculed, because, 
say the physicists and chemists, “ there is but one force in kosmos ” ! 
