74 STUDIES IN ELECTRO-PHYSIOLOGY: 



All this is in perfect harmony with the hypothesis that 

 the impulse is neuro- electrical. The effect of a rise of 

 temperature upon liquid or semi-liquid conductors is to 

 decrease their resistance, or, in other words, to increase their 

 conductivity. It is purely to my mind a question as to 

 which action is precedent, the electrical or the chemical, 

 and I do not think that anyone can, after careful study of 

 the structure of muscular tissue, ganglia, and nerve, doubt 

 that it is the electrical. 



The physical theories in relation to this question 

 compare the nerve impulse to the way in which an electrical 

 charge is propagated along a wire, and, in refutation, the 

 slow rate of conduction in nerve and the phenomenon of 

 inhibition are adduced. 



Now, it is incontrovertibly true that nerve-current will 

 flow along a metallic conductor, but it is abundantly 

 evident that instead of being homogeneous, as a wire is, 

 the conductors of the body are complex. Halliburton 

 tells us that a nervous impulse does not necessarily travel 

 along the same nerve-fibre all the way, and that there is a 

 system of relays. He adds that on the onward propagation 

 of a nerve impulse through a chain of neurons its passage 

 is delayed at each synapse, " hence there is additional 

 ' lost time ' at each of these blocks." And there are very 

 many of them. 



Suppose that, instead of an electric circuit being com- 

 posed of an insulated cable, it was made up of thousands of 

 cables and wires and many thousands of condensers of 

 varying capacity. Would the velocity of the current be 

 the same ? It would not. There would, inevitably, be 

 some " lost time " at many of the condensers by reason 

 of their not receiving instantaneously their full tension 

 charge, and owing to varying degrees of retardation. 



To postulate that the nerve impulse is not of an elec- 

 trical nature is to accuse Nature of introducing into the body 



