INADEQUACY OF PFLUGER'S LAW 



583 



depressing it, during the continuation of the current, a 

 verification, by means of responsive sensations, of Pfliiger's 

 Law. Having thus, with moderate E.M.F. obtained the 

 excitatory effect at kathode, and depressing effect at the 

 anode, by means of the contrasted sensations of intense 

 irritation and soothing, I was next desirous of seeing 

 whether, with low E.M.F., these effects would be reversed. 

 I therefore undertook investigations on a dozen different 

 individuals, to determine the effect of anode and kathode, 

 as the E.M.F. was gradually increased from 3 to 2 volts. 

 It should be mentioned here that the subjects of the 

 experiments were totally ignorant of the object of the 

 investigations, and were simply asked to describe their 

 sensations at different points. Their ages varied from 

 eighteen to twenty-five. As the critical point may undergo 

 some variation with the season, it may be worth while also 

 to mention that the experiments were carried out in 

 summer, in the month of August. 



The following case may be taken as typical : 



POLAR EFFECTS OF E.M.F. OF VARIOUS INTENSITIES ON RESPONSIVE 



SENSATION 



It will thus be seen that the kathode, which, at the 

 moderately intense E.M.F. of 2 volts, induced a painful 

 sensation, owing to the increase of excitability, induced the 

 very opposite effect of depressing excitability at the low 

 E.M.F. of -3 volt. Precisely the reverse, moreover, was the 

 case with the anode. Here, with -3 volt, excitability w?,s 

 found to be enhanced, causing increase of irritation, while, 

 with the moderately strong E.M.F. of 2 volts, it induced the 

 opposite effect of soothing, by depression of excitability. 



