xvi RESEARCHES ON IRRITABILITY OF PLANTS 



versa — Multiple response induced in Biophytum by the 

 passage of constant current — Comparison of sensitiveness of 

 plant and animal — Minimum current for excitation of human 

 tongue — Relatively higher sensitiveness of Biophytum . . 244 



CHAPTER XVIII 



POLAR EFFECTS UNDER STRONG CURRENTS 



Abnormal polar reactions in Protozoa — Transformation of polar 

 reaction in leaf of Mimosa from Type II, to Type III. under 

 strong current — Further transformation to Type IV. under 

 stronger current — Exhibition of Type III. and Type IV. by 

 leaflets of Mimosa, Biophytum, Averrhoa carambola — Law 

 of polar action of strong currents . ... . . 253 



CHAPTER XIX 



VARIATION OF POLAR REACTION UNDER TISSUE 

 MODIFICATION 



Modification of polar reaction under tissue-changes — Effect of 

 age — After-effect of moderate stimulation — Modified polar 

 effect ; excitation at kathode-make and anode-make ; excita- 

 tion at kathode-make, kathode-break, and anode-make — 

 General review of polar reactions . . . . . 266 



CHAPTER XX 



MULTIPLE AND AUTOMATIC RESPONSE 



The Oscillating Recorder — Latent period of Biophytum — Refrac- 

 tory period — Response on ' all-or-none ' principle — Multiple 

 electrical response to a single strong stimulus — Multiple 

 mechanical response to strong stimulus in Biophytum and 

 Averrhoa — Continuity of multiple and automatic response — 

 Ordinarily responding Biophytum converted into automatically 

 responding condition by excess of stored energy — Automati- 

 cally responding Desmodium converted to ordinarily respond- 

 ing condition by depletion of stored energy . . . .278 



CHAPTER XXI 



THE AUTOMATIC PULSATIONS OF DESMODIUM GYRANS 



Activity of detached leaflet of Desmodium — Pulsation maintained 

 uniform under constant internal hydrostatic pressure — The 

 plant-chamber — Time- relations of pulsating movement derived 



