I 



CONTENTS xxv 



gation Morographic record by variation of resistivity Inversion of 

 curves at death-point Similarities between mechanical, electro-motive 

 and resistivity curves of death The true excitatory effect attended by 

 diminution of resistance Response of plant nerve by resistivity varia- 

 tion Independence of resistivity and mechanical variations Responsive 

 resistivity variation in frog's nerve, and its modification under anaesthetics 540 



CHAPTER XXXVIII 



FUNCTIONS OF VEGETAL NERVE 



jble conducting power of cortical tissues Heliotropic and geotropic 

 effects dependent on response of cortical tissues only Phenomenon of 

 correlation Excitability of tissue maintained in normal condition only 

 under action of stimulus Physiological activities of growth, ascent of 

 sap, and motile sensibility, maintained by action of stimulus Critical 

 importance of energy of light Leaf- venation a catchment-basin Trans- 

 mission of energy to remotest parts of plants Plant thus a connected 

 and organised entity . . . . . . . . . 551 



CHAPTER XXXIX 



ELECTROTONUS 







ctra-polar effects of electrotonic currents on vegetal nerve Electrotonic 

 variation of excitability Bernstein's polarisation decrement Hermann's 

 polarisation increment Investigation into the law of electrotonic varia- 

 tion of conductivity Investigation on variation of excitability Con- 

 ductivity enhanced when excitation travels from places lower to higher 

 electric potential, and depressed in opposite direction When feeble, 

 anode enhances and kathode depresses excitability All electrotonic 

 phenomena reducible to combined action of these factors Explanation 

 of apparent anomalies .......... 560 



CHAPTER XL 



INADEQUACY OF PFLUGER'S LAW 



Reversal of Pfliiger's Law under high E.M.F. Similar reversals under 

 feeble E.M.F. Investigation by responsive sensation Experiments on 

 living wounds Under moderate E.M.F., intensity of sensation enhanced 

 at kathode, and depressed at anode Under feeble E.M.F., sensation 

 intensified at anode and depressed at kathode Application of electrical 

 currents in medical practice ........ 578 



