ELECTRIC ACTION IN PLANTS. 225 



way claimed by Burdon-Sanderson. Changes in the 

 electric action also occur during the curvature, but 

 these changes do not correspond with negative varia- 

 tion in the nerve-current ; they are probably connected 

 with the circulation of the sap within the leaf. From 

 my own study of Mimosa pudica I had already adopted 

 similar views. In this plant I was unable to detect 

 regular electric action during quiescence ; but on the 

 falling of the leaf-stalk, I observed electric currents 

 which might be explained as the result of the circu- 

 lation of the sap. We must, therefore, be content to 

 accept the fact that electric phenomena in plants are 

 not to be classed with those observed in muscles, 

 glands, nerves, and in the electric organs of certain 

 fishes. 



11 



