A. B. Plowman — Electromotive Force in Plants. 103 



cates a still further reduction of the resistance. At IX the 

 lower contact point of the stem was heated to ignition over 

 an alcohol flame. The maximum current appeared when the 



6P..&L, 



Fig. 13. 



\9A.M.y^T2M. 3P.M. 6P.M. $A 



Normal Current . 



Poinsettia. 



Fig. 14a. 

 (Poinsettia) 



x\/ *TV' 



A 



/ ... v 



Fig. 14. 

 Reaction Currents 

 Poinsettia. 



VI. ! Xvii. 



VIII. 



stem was about two-thirds burned off, after which the current 

 decreased slowly until the stem broke under its own weight 

 at X in the figure. 



The explanation of all these phenomena comes naturally 

 within the domain of physical chemistry. Thus, the applica- 



