ILLUSTRATIONS xli 



FIG. 1'AOE 



331. Response Records by Resistivity Variation, in the Nerve of Fern . 548 



332. Effect of Chloroform seen in Modification of Resistivity Variation in 



Frog's Nerve . . . . . . . . . 55 



333. Photographic Record of Effect of Tetanisation in Enhancing Mechani- 



cal Response of Plant-nerve . . . . .... 554 



334. Photographic Record showing Enhancement of Excitability under 



Action of Light in Nerve of Fern 557 



335. Distribution of Fibro-vascular Elements in Single Layer of Stem of 



Papaya 558 



336. Extra-polar Kat-electrotonic Effect ....... 560 



337. Extra-polar An-electrotonic Effect ....... 560 



338. Extra-polar Electrotonic Effects under an Acting E.M.F. which rises 



from -6 to I -4 Volts ......... 561 



339. Diagram illustrating Bernstein's Decrement of Kat-electrotonic Current 562 



340. Diagram illustrating Bernstein's Decrement of An-electrotonic Current 562 



341. Diagram representing Hermann's Polarisation-increment under 



Tetanising Shocks, with reversed polarising Current . . . 563 



342. Diagram representing Hermann's Polarisation-increment under 



Tetanising Shocks, with reversed polarising Current . . . 363 



343. Experiment with Petiole of Fern demonstrating Variation of Con- 



ductivity by Polarising Current, Excitation travelling electrically 

 Downhill 565 



344. Experiment with Petiole of Fern demonstrating Variation of Con- 



ductivity by Polarising Current, Excitation travelling electrically 

 Uphill . 565 



345. Photographic Records of Responses taken in last Experiment, when 



Excitation was transmitted with and against the Polarising Current. 566 



346. Photographic Record of Modification of Conduction during Passage 



of Excitation from Anodic to Kathodic Region, under Increasing 

 Intensity of Polarising E.M.F. ....... 567 



347. Photographic Record showing Enhanced Conduction from Kathodic 



to Anodic Region .......... 568 



348. Experimental Arrangement to Exhibit the Enhancement of Excita- 



bility at Anode, when the Acting E.M.F. is feeble . . . 569 



349. Experimental Arrangement to Exhibit Depression of Excitability at 



Kathode, when the Acting E.M.F. is feeble ..... 569 



350. Photographic Records of Response, illustrating the Enhancement of 



Excitability at Anode, and Depression at Kathode, under Feeble 

 Acting E.M.F. in two Specimens of Nerve of Fern a and b . . 570 



351. Experimental Arrangement demonstrating the Joint Effects of 



Variation of Conductivity and Excitability by Polarising Current . 572 



352. Experimental Arrangement demonstrating the Joint Effects of 



Variation of Conductivity and Excitability by Polarising Current, 

 when Current is Reversed ........ 572 



353. Photographic Record of Response under the Arrangements given in 



Figs. 351, 352 in Nerve of Fern . . . . . . . 572 



354. Experimental Arrangements for Showing so-called Polarisation 



increment by the Joint Effect of Increased Excitability at Anode 



and Enhanced Conduction of Excitation electrically Uphill . . 574 



