274 RESEARCHES ON IRRITABILITY OF PLANTS 



vanishing of Type Km Ab and a substitution of the transi- 

 tional type Km Am. It may be mentioned here that in 

 some cases this characteristic excitation, at make only of 

 both kathode and anode, was found to persist through an 

 extended range of current-intensities. The resemblance of 

 this type to the response of Amphistigma is obvious. 



Table VII. — Experimental Results with Different Specimens 

 Exhibiting Km Am Effect 



Modified Response Km Kb Am 



If the excitatory efficiency of Ab were to fall still further, 

 it might be reduced even lower than the excitatory effective- 

 ness of kathode-break. In such a case, with a given current, 

 excitation would be less for Ab than for Am or Kb. Hence 

 the anode-break effect would vanish and the excitatory 

 formula for this type under a certain intensity of current 

 would be Km Kb Am, and this we may call III., Transitional. 

 It is interesting to find that this particular responsive 

 modification is not seldom obtained, especially with leaves 

 the petioles of which are very thin. 



