192 Professor Jagadis Chunder Bose [May 29, 



ways. First by the selection of a thin leaf -stalk instead of a thick 

 stem for the purpose of the experiment, so that the access of the 

 solution to the interior became less difficult. In the second place by 

 the employment of strong non-volatile toxic agents like solutions 

 of copper sulphate or of potassium cyanide. The choice of a strong 

 poison was deemed advisable, because the absorption of even a small 

 quantity might in such a case prove effective in abolishing the con- 

 ducting power. My anticipations were fully justified. By the ap- 

 plication of copper sulphate, the conducting power was found arrested 

 in the course of twenty minutes. But the more deadly cyanide 

 solution abohshed the conducting power in a period as short as five 

 minutes (Fig. 15). 



Fig. 15. — Abolition of Conduction by Local Applica- 

 tion OF Potassium Cyanide. (1) Normal record ; 

 (2) Arrest of conduction after application for five 

 minutes ; (3) Persistent abolition of conduction, even 

 when stimulus was increased fifteen-fold ; (4j Record 

 of direct stimulation. 



Accounts have thus been given of some typical experiments by 

 which the nervous impulse is discriminated from the mechanical 

 impulse. It has been shown that excitation may be initiated and 

 transmitted in the plant in the complete absence of any mechanical 

 disturbance. It has been shown that the various conditions which 

 accelerate, retard, or arrest the nervous impulse in the animal also 

 enhance, retard, or block the impulse in the plant in a manner which 

 is identical. I have, moreover, from my investigations on the plant- 

 nerve led to the discovery of certain hitherto unknown characteristics 

 of the animal nerve. The investigation on the simplest type of plant- 

 nerve is expected to cast a flood of light on the obscure phenomenon 

 of nervous impulse in general, and the causes operative in bringing 

 about the degeneration of the normal function of the nerve. 



