x ELECTROMOTIVE ACTION IN NERVE 303 



distinctness. On passing a constant current there is at the 

 kathode only, on closing the current, at the anode on breaking it, 

 " an effect, albeit brief and inconspicuous, in the direction of 

 negativity of the proximal electrode." " This momentary negative 

 effect is much more visible when single induction shocks are sent 

 into the ' exciting tract ' by a key. A brief negative effect 

 corresponds with each such shock, independent of its direction" 

 Alternating currents produce negativity of the proximal electrode, 

 which lasts as long as the " tetanisation." " Analysis by the 

 differential rheotome also shows that a wave of negativity (i.e. 

 katelectrotonus) is transmitted at these distances," it being a 

 matter of indifference whether short, frequent battery currents, 

 or induction shocks, are led through the exciting tract by the 

 rheotome. " Both cases exhibit the wave of negativity spreading 

 over the tract led off, in two phases, so that the proximal 

 electrode is first negative and then positive to the distal contact." 

 Such complete identification of the negativity which is the 

 concomitant of excitation, with the katelectrotonic wave, must be 

 protested against, in spite of the many striking analogies between 

 these phenomena in the core-model, and the galvanic reaction of 

 medullated nerve traversed by the current. The objections which 

 we hold to be conclusive against such a point of view are, in the 

 first place, the appearance of analogous galvanic manifestations in 

 electrical excitation of the most diverse " irritable " tissues, the 

 structure of which in no way justifies us in assuming that they 

 are core-conductors in the same sense as medullated nerve ; further, 

 the fact that etherised medullated nerves, in which physical 

 " fixed polarisation " appears after, as well as previously, exhibit 

 no trace of transmitted activity ; and lastly, and above all, the fact 

 that the galvanic manifestations of excitation appear equally in 

 all appropriate objects witli other than electrical stimulation. 

 Boruttau, indeed, does not hesitate to refer once more to the 

 properties of the core-conductor. He sees an analogue to the 

 mechanical excitation of nerve and its galvanic consequences in 

 the sudden rupture of the wire inside the moist sheath, after 

 previously filing it at a given point, since he then observed in 

 every case " with great precision," on leading off from a remote 

 tract, " a comparatively conspicuous momentary appearance of 

 current, or charge, followed by an immediate return to the previous 

 state of rest." Without disputing these experimental data, no 



