CONTENTS xv 



CHAPTER XIV 



POLAR EFFECTS OF ELECTRICAL CURRENT IN 

 EXCITATION OF PLANTS 



PAGE 



Polar excitation in animal tissues — Anomalous reactions in Pro- 

 tozoa — Mono-polar method — Current Reverser — Excitatory 

 polar action in plant — Method of record — Effects of ascending 

 and descending currents in animal and plant — Records giving 

 time-relations — Potential slide — Measurement of e.m.f. and 

 current — Potential keyboard . . . . . . 198 



CHAPTER XV 



POLAR EFFECTS OF FEEBLE AND MODERATE CURRENTS 

 ON VARIOUS SENSITIVE PLANTS 



Polar effects of feeble and moderate currents on (1) leaflets of 

 Mimosa, (2) leaflets of Biophytutn, (3) leaflets of Neptunia, 

 (4) leaflets of Averrhoa carambola, (5) leaflets of Averrhoa 

 bilimbi, and (6) primary leaf of Mimosa — Excitation with 

 feeble current only at kathode-make — Excitation at kathode- 

 make and anode-break, under moderate current — Tabular 

 statement of results . . . . . . . . 212 



CHAPTER XVI 



THE CONTRASTED EFFECTS OF ANODE AND KATHODE 



Polar effects of currents on pulsation of Desmodium gyrans — 

 Reduction of systolic contraction by anodic action — Diminu- 

 tion of diastolic expansion by kathodic action — Arrest at 

 systole by make of kathode and diastolic expansion by break 

 of kathode — Arrest at diastole by make of anode, and systolic 

 contraction by break of anode — Effects of ascending and 

 descending currents of feeble and strong intensity in nerve- 

 and-muscle preparation — Parallel effects in petiole-and-pul- 

 vinus .......... 234 



CHAPTER XVII 



EFFECT OF TEMPERATURE ON POLAR EXCITATION, AND 

 MULTIPLE EXCITATION UNDER CONSTANT CURRENT 



Excitability of nerve to induction-shock diminished by cooling — 

 Nerve excitation by constant current enhanced by cooling — 

 Excitation of conducting-tissue of Mimosa by constant 

 current enhanced by cooling and depressed by warming — 

 Ineffective stimulus becoming effective under cooling and vice 



