Apparatus for study of variation of ex­cit­abil­ity—Uniform periodic stimulation—​The Response Recorder—Effects of external condition on ex­cit­abil­ity—​Effects of light and darkness—​Effect of excessive turgor—​Influence of temperature—​Diurnal variation of ex­cit­abil­ity—​Effect of physio­logic­al inertia[43]

V.—RESPONSE OF PETIOLE-PULVINUS PREPARATION OF MIMOSA.

Effect of wound or section in modi­fi­ca­tion of normal ex­cit­abil­ity—​The change of ex­cit­abil­ity after immersion in water—​Quantitative determination of the rate of decay of ex­cit­abil­ity in an isolated preparation—​Effect of amputation of upper half of the pulvinus—​Effect of removal of the lower half—​Influence of weight of leaf on rapidity of responsive fall—​The action of chemical agents—​Effect of “fatigue” on response—The action of light and darkness on ex­cit­abil­ity[73]

VI.—CONDUCTION OF EXCITATION IN PLANTS.

Hydro-dynamic versus physio­logic­al theory of conduction of excitation—​Arrest of conductivity by physio­logic­al blocks—​Convection and conduction of excitation—​Effect of temperature on velocity—​Effect of season—​Effect of age—​Effect of dessication of conduct­ing tissue—Influence of tonic condition on conduction—​Effect of intensity of stimulus on velocity of trans­mission—​Effect of stimulus on sub-tonic tissues and tissues in optimum condition—​Canalisation of conduct­ing path by stimulus—​Effect of injury on conductivity[97]

VII.—ELECTRIC CONTROL OF EXCITATORY IMPULSE.

Method of conductivity-balance—Control of transmitted excitation in Averrhoa bilimbi by electric current—​‘Uphill’ trans­mission—​Transmission ‘downhill’—Electric control of nervous impulse in animal—Directive action of current on conduction of excitation—Effects of direction of current on velocity of trans­mission in Mimosa—Determination of variation of conductivity by method of Minimal Stimulus and Response—Influence of direction of current on conduction of excitation in animal nerve—Variation of velocity of trans­mission—After-effects on Heterodromous and Homodromous currents—Laws of variation of nervous conduction under electric current[107]

VIII.—EFFECT OF INDIRECT STIMULUS ON PULVINATED ORGANS.

Conduction of excitation—Dual character of the transmitted impulse—​Effect of distance of application of stimulus—Periods of trans­mission of positive and negative impulses—Effects of Direct and Indirect stimulus[135]

IX.—MODIFYING INFLUENCE OF TONIC CONDITION ON RESPONSE.