The Nervous Mechanism of Plants

Ascent of sap, not concerned in transmission of excitation 20 Automatic record of velocity of transmission 54 20‘; Autonomous activity in Desmodium. ng, 202 ; ‘in growing organs 119 Averrhoa Cammhola, irreciprocal conduction in, 47 ; dirertiof of preferential conduction in, 50 ; dual impulses under indirect stimulation Biophytmn sensiiivum. irreciprocal conduction in, 48 ; direction of preferential conduction in, 50; polar excitation of, 26; simultaneous determination of translocation of stimulant and transmission of excitation in, iS

Block, forcing of under strong stimulus, 41 ; physiological, 71 206 ■ electrotonic, 29, 75 ; by cold, 72 ; by poison, 76 „ disappearance of central, under strychnine, 197 ,, Method of natural, for electric response, 99 Cellular propagation of excitation, qx Chenii cal agents, effect of, on conductivity, 131 Cold, block of conduction by excessive, 72 Conducting tissue, anatomy of, in petiole, 32, 206 ; in stem, 39 ; localisation of by Electric Probe, iio, 209 Conduction, between stem and leaves, 6, 40

Constant electric current, polar excitatory action of, 22 ; directive action of, on conduction, 133,. 138; bomodromous and heterodromous, 141, Continuity, of conduction between stem and leaves, 6, 40 ; between irreciprocal and preferential conduction, 48, 208 Contractility, 119 Desiccation, effect of on conduction, 69 Desmodium gyrans^ 119, 165, 202 Dia-heliotropic attitude of leaves, 160 Differential method of determining velocity, 62 „ staining, for tracing nerve-distribution, 35 Diffuse excitation, under intense stimulation, 41 ; error introducedby, 12 Di-phasic method, for determination of velocity of impulse, 107 response, mechanical, 84 ; electrical, 98 Direct and indirect stimulation, responsive movements to, 83 ; effects of, on growth, 90 ; laws of, 94, 211

Distance, effect of, on transmission, 85 Distribution of conducting tissue, 207 Dual character of impulse, 83 Dutrochet, quoted, 9 Effectors, four distinct in pulvinus of Mimosa, 152, 166, 214 Efferent impulse, relation between afferent and, 183 ; special nerve for conduction of, 188 Einthoven galvanometer, record of electric response with, 103, 109, 114 Electric current, after-effect of, on conduction, 141 j polar excitation bv, 26 ; variation of velocity of conduction in animal nerve by* 144 * in plant nerve by, 138 ,, Probe, localisation of conducting nerve by, no ,, response, of ordinary plants to direct stimulation, 95 ; to indirect stimulation, 96

of Mimosa, to indirect stimulation, 105 Electrotonic block of conduction, 29, 75, 206 Efythrina indica, 165 Excitability, differential, in pulvinule of Cassia, 157 ; in petiole of Helianthus, 163 ; in pulvinus of Mimosa, 163 Excitatory process, independent of contractile process, 107, 179 Fatigue, effect of, on conduction, 51 ; on latent period, 60 Galvan OMETRic negativity, concomitance of, with diminished turgor lo v positivity, with increased turgor, 104 " ’

Growth, effect of direct and indirect stimulation on, go Haberlandt, on conducting phloem, 10 ; on hydro -mechanical theory of Heterodromous and Homodromous current, direct and after-effect on conduction, 213 ; in animal nerve, 147 ; in plant-nerve, 141 High Magnification Crescograph, 90 Hydro -mechanical theory of transmission, 8 ; untenability of, 21, 31 characteristics of, 85 Innervation of pulvinus of Mimosa, 166 Irreciprocal conduction, at neuro-muscular junction, 44 ; at nervepulvinus junction, 45 ; in stem of Mimosa pudica, 46 ; in petiole of M . Spegaszinii, 46 ; in petiole of Averrhoa, 47 ; in petiole of Biophytum, 48 ; continuity between, and preferential, 48

Latent period, determination of, in pulvinus, 59 ; effect of fatigue on, 60 ; effect of variation of temperature on, 60 Lateral stimulation, by light, 91, 155 ; by other agents, 156 Laws of. Polar excitation, 26 ; directive action of current on conduction, 148, 214 ; effects of direct and indirect stimulation, 103, 211 ,* torsional response, 156, 214 Leaf, dia-heliotropic attitude of, 160 ; as catchment-basin for stimulus, 120 ; nervous control of attitude of, 214 Light, transmitted impulse under stimulus of, 89, 168 ; torsional movements under vertical, 157

Localisation of Nerve by Electric Probe, no, 209 * Lost time ’ in reflex, 193, 217 ; abolition of, under strychnine, 197 Mimosa pudica, conducting strands in, 32 ; longitudinal conduction of excitation in stem, 4 ; in petiole, 60 ; transverse conduction in stem, 88 ; positive and negative impulses in, 89 ; electric response of, 105 , , Spegazzinii, 1 9 ; transmission of excitation under minimal and maximal stimulus, 46 ; translocation of stimulant and transmission of excitation in, 20 ; irreciprocal conduction in, 46 Modes of stimulation, 2 Monophasic response, time-relations of, 103 Motile organ, complexity of, 152, 214; and attitude of leaf, 160 ,, organs, relative sensibility of, 179 Motor impulse in Mimosa, 176 ; separate conducting nerves for sensory and, 187, 216

Motor and sensory nerves, in animal, 187 ; in plant, iSS Movement of sap, independence of transmission of excitation of, 20 ; simultaneous determination of, and transmission of excitation, 18 Nerve-connection, between stem and leaves, 40 ; between centre and periphery, 1 73 ; between sub-petioles and quadrants of pulvinus, determination of, by peripheral stimulation, 167; by central stimulation, Nerve-excitation," irradiation of, 178 Nerve, similarity of response in plant and animal, 133 Nervous conduction, laws of variation of, under constant current, 148 „ control of attitude of leaf, 214 ,, impulse, electric control of, 135

,, tissue in Mimosa, localisation of, by Electric Probe, no Optical Lever, 87 Ordinary plants, electric response of, 95 ; transmitted impulse in, 97 ; monophasic and diphasic response of, 98 Paralysis of conduction by local application of cold, and removal by induction-shocks, 74 Petiole-laminar preparation, electric response of, 100 ,, -pulvinar junction, anatomy of, 151 Pfeffer, on hydro-mechanical theory of transmission, 8 ; on effect of chloroform on petiole, 37

Phloem, as conductor of excitation, 10, 35 ; tubular cells in, 37 ,, conduction of sensory and motor impulses by, 189 ,, external and internal, demonstration of, by staining, 35 ,, localisation by Electric Probe, no Phototropic effect of light of different colours, 156 Plant-nerve, response of isolated, to indirect stimulation, 127 ; aftereffect of tetanisation, 126; similarity of response to that of Frog’s ' " nerve, 12S - . Positive electric response to indirect stimulation, in ordinary plants, 97 ; in Mimosa, 1 06 ; in animal ureter, 1 1 6 ,, mechanical response, characteristics of, 86 Protoplasmic irritability, diverse manifestations of, 118 Pulvinus of Mimosa pudica, complexity of, 151, 214 ; four effectors in, 1 52 ; response of different quadrants to direct and indirect stimulation^

Reflected impulses in IMiinosa, on stimulation of the several subpetioles, 180 Ricca, transpiration-current theory of conduction of excitation, 13, 203 Scratch-stimulation, 3 Sensory impulse in Mimosa, 187; difference between motor and, iSS ; separate conducting nerves for motor and, 187 ,, nerve, localisation of, 191 ^ Stimuiation, modes of; by scratch, 2 ; by friction, 14 ; by inductionshock, 2 ; by polar action of constant current, 22 ; by light, 92, 155, 159, 164, 168; electro-thermal, 16,99; by gravity, 156 ; effect of intensity of on conduction, 4 ; quantitative, 54 ; after-effect of, on conduction, 67, 125 ; opposite effects of, feeble and strong, 106 ; on sub-tonic and normal tissues, 1 19, 205 Stimulus, A and D effects of, 117 ; internal and external work done by, 1 1 7; leaf, a catchment-basin for, 120 Sub-tonicity, effect of, on conduction in plant and animal nerve, 126 ; on motor excitability and rhythmicity, 119 Sun-flower, dia-heliotropic adjustment of leaf of, 1 63 ; heliotropic curvature of stem of, 91, 164 ; differential excitability of petiole of, 163

Synapsoidal membrane, effect of, on conduction in plants, 48, 52 Strychnine, effect of, in abolition of block at centre, 196, 218 Tetanisation, similar after-effect on conduction in plant and animal nerve, 126 Transmitted impulse, excitatory character of, 22 ; positive and negative, 83 ; intensity of stimulus and effect of tonic condition on, 86 Transpiration-current theory of conduction of excitation, 13, 15, 203 ; unfounded character of, 20 Transverse conduction, in stem of Mimosa, 88 ; in pulvinus, 92, 114 Turgor, effect of .variation of, on mechanical response, 81 ; on growth, 90

Unilateral stimulation, longitudinal conduction of, in stem, 4 ; transverse conduction of, in stem, 89 ; in induction of Eeliotropic curvature, 91 ; transverse conduction of, in pulvinus, 91, 114 Velocity of transmission of excitation, determination of, by ordinary method, 6g ; by differential method, 62 ; in thick petiole, 63 ; in thin petiole, 64 * by diphasic electric response, 107, 209 , , ,, effect of desiccation on, 69 ; of variation of temperature, 70 ;

effect of direction of constant current on, in animal nerve, 144; in plant-nerve, 139 Water-gap, transmission of excitation across, 13, 15 Wound-stimulation, complications of, II, 13 Printed in England at The Ballantyne Press Spottiswoode, Baolantyne & Co. Ltd. Colchester^ London ^ Eton