EXCITATORY POLAR EFFECTS OF CURRENTS 



195 



response was observed at the kathode at charge. The 

 excitatory wave travelled in both directions, and five pairs 

 of leaflets were depressed. There was no effect at the anode. 

 At discharge, the former anode became kathode, and there 

 was a responsive movement of the leaflets near that point. 



In the following table, the characteristic polar effects of 

 feeble E.M.F. may be seen at a glance. 



Table showing the Polar Effects of Feeble E.M.F. 



Effects of moderate E.M.F. -From this point onwards 

 it will be found sufficient to describe the results obtained 

 by means of the bi-polar method of excitation, this mode 

 of investigation being 

 more complete than 

 the mono-polar. 



With regard to 

 the first of these, a 

 number of experi- 

 ments were performed 

 on a single specimen 

 of Biophytum, using 

 an E.M.F. of 24 volts. 

 The excitatory wave 

 at make was found 

 to be initiated at ka- 

 thode, and to travel 

 in both directions, 

 causing the depres- 

 sion of nine pairs of 



leaflets. The forward half of this wave of excitation only 

 stopped at one pair of leaflets before the anode (fig. 92). This, 



Fig. 92. 



(a 



Make-kathode and Break-anode 

 Effects in Biophytum 



Shows effect at make, excitation being 

 produced at kathode ; (/') shows effect at 

 break, excitation being now produced at 

 anode. 



