362 INHIBITION BY EXCITATION AND 



in this way to produce artificially what may be called a reversed 

 muscle current. 



In the work just quoted, I mentioned experiments which I 

 performed at that time with Na 2 CO 3 and other agents calculated 

 to increase the excitability of muscle substance, in the hope that 

 I might succeed in making- by their local action, certain points 

 positive in regard to others. The low degree of sensitiveness of 

 the instrument, which alone was then at my disposal, an old 

 Meyerstein mirror galvanometer, did not make it possible to answer 

 the question decidedly. 



I have recently resumed these experiments, and have convinced 

 myself that after local treatment with dilute solutions of Na 2 CO 3 , 

 Na Cl, or veratrine, the differences of tension anticipated can be de- 

 monstrated very easily and with great certainty. 



If the uninjured lower end of a sartorius is dipped for a short 

 time (5-10 min.) in a 0-5-1% solution of Na 2 CO 3 (a 2-4% NaCl 

 solution proves less efficient) it will be found more or less positive 

 in regard to the middle of the muscle. Under these circumstances 

 employing muscles that were previously currentless, deflections of 

 + 200 scale divisions and upwards with the Hermann galvanometer 

 which I used, were by no means of rare occurrence. Feeble normal 

 currents are got rid of or even reversed. The (reversed) ' soda 

 currents ' may be again got rid of by a rather long washing with 

 a physiological solution of common salt, though less easily than 

 * potash currents.' 



Now, disregarding other differences, one very essential difference 

 exists between the result, just discussed, of the direct action of 

 certain chemical substances, and the positive kathodic polarisation 

 which arises from the electrical excitation of uninjured currentless 

 muscles. In the latter case, as has been already mentioned, it is 

 obvious that we are dealing with an indirect effect of the current, 

 with a ' Reaction ' of the muscle substance from the primary 

 process of excitation produced at the kathode. The chief fact in 

 support of this is, that after a longer duration of closing or with 

 less favourable preparations, a negative preliminary jerk often 

 precedes the positive deflection, as was shown above, and that in 

 less sensitive muscles (especially in those of JR. esculentd) there seems 

 to be only a trace of positive kathodic polarisation, or it is altogether 

 absent. With reference to this, I must remark further, that the 

 positive reaction at the kathode does not, as it seems, stand in 

 direct dependence upon the condition of excitability of the kathodic 



