1 86 PLANT RESPONSE 



Table showing Effect of Electrotonus on Death-point 



The effect here described takes place, as has been said, 

 where the electromotive force is not excessive. Under these 

 conditions, it is the kathode which is the more excitable. I 

 have, however, discovered a very curious case of inversion of 

 excitation which occurs when the E.M.F. exceeds a certain 

 value. With high electromotive force, then, it is the anode 

 which excites at make of the circuit. The demonstration of 

 this fact by means of mechanical response, and subsidiary 

 proof by means of death-response, will be given in detail in a 

 subsequent chapter. 



Summary 



The death-point is lowered by fatigue, the amount of 

 lowering depending on the intensity of fatigue. 



The characteristic thermo-mechanical curve is modified 

 and the point of inversion translocated by the action of 

 chemical reagents. 



Certain reagents produce a duplication of the rigor-point. 



The death-point is translocated to a temperature lower 

 than normal by the action of poisonous reagents. 



Under standard conditions, there is a definite interval be- 

 tween the death point and discoloration-point of vegetable 

 tissue. 



Hence it is possible to obtain thermographs of localised 

 effects of various agents. 



The excitatory effect of kathode is demonstrated by the 

 earlier discoloration produced there. 



