236 RESEARCHES ON IRRITABILITY OF PLANTS 



effects are easy to demonstrate, the current applied being of 

 moderate intensity. In fig. 116 is seen the anodic effect ; the 

 first two pulsations are normal, after which the anode was 

 applied. This is seen to result in a continuous lessening 

 of the height of successive contractions. 



The application of kathode, on the other hand, is found 

 to induce a precisely opposite effect (fig. 117) ; here the 

 diastolic expansion is opposed, which results in a con- 

 tinuously diminishing relaxation. In fig. 116 a line joining 



Fig. 116. — Effect of anode, opposing 

 contraction in pulsation of 

 Desmodium gyrans. Note the 

 gradual diminution of systolic 

 contraction. 



Fig. 117. — Effect of kathode, op- 

 posing expansion. Note the 

 gradual diminution of diastolic 

 expansion. 



the apices of successive contractions is seen to descend, 

 while in fig. 117, under the action of kathode, the line joining 

 the extreme points of the diastolic excursion is seen to 

 ascend. The same fact is seen again in fig. 118, where a 

 single specimen is subjected first to anode and then to 

 kathode. The contrasted effects of anode and kathode 

 in this case are very obvious. 



By employing a suitable intensity of current it is some- 

 times possible to exhibit the contrasted effects of the 

 kathode and anode by the actual arrest of pulsation. By 

 the make of kathode the arrest takes place towards systole, 

 and by the make of anode towards diastole. In such cases 



