(illip i. H. Htll TJJtbrara # Nortli (Carolina ^tate Imtipraita B6 S00298252 S THIS BOOK IS DUE ON THE DATE INDICATED BELOW AND IS SUB- JECT TO AN OVERDUE FINE AS POSTED AT THE CIRCULATION DESK. nyti 9 ^ ? o 1975 w^R30« PLANT RESPONSE WORKS BY THE SAME AUTHOR. RESPONSE IN THE LIVING AND NON- LIVING. With 117 Illustrations. Svo. 10s. 6^. 1902. . ELECTRO-PHYSIOLOGY OF PLANTS. {To be published shortly.) LONGMANS, GREEN, \ CO., .59 Paternoster Row, Londc N\w ^'ork and Bombay. PLANT RESPONSE AS A MEANS OF ^^ ^ PHYSIOLOGICAL INVESTIGATION BY JAGADIS CHUNDER ROSE, M.A., D.Sc. PROFESSOR, PRESIDENCY COLLEGE, CALCUTTA WITH ILLUSTRATIONS LONGMANS, GREEN, AND CO. 3 9 PATERNOSTER ROW, LONDON NEW YORK AND BOMBAY 1906 All riwhls rer-ervod TTit rv'^ ^\<' \\l XT, [^ PREFACE The investigations described in the present volume have been an outcome of my work on the Similarity of Responsive Phenomena in Inorganic and Living Matter, first com- municated as a Memoir to the Science Congress at Paris, in August 1900,^ and subsequently expanded into greater detail in my book on ' Response in the Living and Non-Living.' The electrical responses described in the Memoir referred to, had been obtained by the method of conductivity variation. The same problem was next attacked by a different mode of investigation, response being now obtained by electromotive variation.- Believing in the continuity of responsive pheno- mena in the inorganic and organic, I undertook on that occasion to demonstrate by the same method the electrical response of ordinary plants, and to show that every plant, and every organ of every plant, was excitable. It was then generally believed that so-called 'sensitive' plants alone ex- hibited excitation by electrical response, and the proposition that ordinary plants also showed excitatory electrical response to mechanical stimulation, and that such response was appro- priately modified under physiological changes, was much controverted. I have to thank Professor Sidney H. Vines, ' ' De la Gencralite des Phenomenes Moleculaires produils par PElectricite sur la Matiere Inorganique et sur la Matiere Vivante. ' (Travaux dtc Congr^s International de Physique. Paris, 1900.) - Paper read before Royal Society, June 6, 1901. Also P'riday Evening Discourse, Royal Institution, May 10, 1901. viii PLANT RKSrOXSK at that time President, for the facilities which he then afforded mc for the full publication of my results in the ' Journal ' of the Linnean Society, and for the warm interest which he has manifested in my work, both then and later. I next undertook to demonstrate that all the important characteristics of the responses exhibited by even the most highly differentiated animal tissues, were also to be found in those of the plant' In m)' previous investigations I had shown that the tissues even of ordinar)' plants gave electrical signs of excitatory response. I now undertook an inquiry as to why they should not also exhibit response by mechanical indications ; and I was surprised to disco\er that ordinary plants, usually re- garded as insensitive, ga\e motile responses, which had hitherto passed unnoticed. From the point of view of its movements a plant may be regarded in either of two ways : in the first place as a mysterious entity, with regard to whose working no law can be definitely predicated, or in the second place, simply as a machine, transforming the energy supplied to it, in ways more or less capable of mechanical explanation. Its move- ments are apparently so di\'erse that the former of these hypotheses might well seem to be the only alternativ'e. Light, for example, induces sometimes positi\e curvature, sometimes negatixe. Gra\itation, again, induces one mo\e- ment in the root, and the opposite in the shoot. From these and other reactions it would appear as if the organism had been endowed with various specific sensibilities for its own advantage, and that a consistent mechanical explanation of its movements was therefore out of the question. In spite of this, however, I have attempted to show that the plant may nevertheless be regarded as a machine, and that its movements in response to external stimuli, though apparently ' Paper read hefure Renal .Society, I'eljniary 4. 1904. TREFACE ix SO various, are ultimately reducible to a fundamental unity of reaction. This demonstration has been the object of the present work, and not that treatment of known aspects of plant- movements which is to be found detailed together with the history of the subject, in standard books of reference on plant physiology, such as those of Sachs, Pfeffer, Strasburger, Darwin, Francis Darwin, Vines, and Detmer. In analysing plant-movements the greatest complexity arises from the confusion of effects due to internal energy and external stimulus respectively. I have, however, been able to discriminate the characteristic expressions of these two factors, and thus to disentangle the complex phenomena which result from their combined action. Another very obscure problem is found in the nature of so-called ' spon- taneous or autonomous ' movements. By the discover}', however, of multiple response, and by the continuity which I have been able to establish, as existing between multiple and autonomous responses, it has been found possible to demon- strate that there are, strictly speaking, no ' spontaneous ' movements, those known by this name being really due to external stimulus previously absorbed by the organism. Thus all the experiments ha\e tended to show that the phenomenon of life does not, as such, connote any intrusion into the realm of the organic of a force which would interfere with that law of the Conservation of Energy which is known to hold good in the inorganic world. The elucidation of the fact that such varied and obscure phenomena in the life-processes of the plant, as, for instance, growth and the ascent of sap, are fundamentally due to the same excitatory reactions as are seen otherwise exemplified in the simple mechanical response now familiar to us, con- stituted a further result which, at the outset of the investiga- tion, was little to be foreseen. X PLANT RESPONSE It has been shown finally that there is no physiological response given by the most highly organised animal tissue that is not also to be met with in the plant. This was proved in detail in the case of the identical polar effects induced in both by electrical currents ; in the conduction of the excitatory impulse to a distance ; in the possibility of detecting the excitatory wave in transit and measuring its rate ; and in the appropriate modification of its velocity by different agencies, even in the case of ordinary plants ; in the passing of multiple into autonomous response in vegetable tissues ; in the light thrown by this phenomenon on the causes of rhythmicity in animal tissues ; in the similar effects of drugs on animal and vegetable tissues, and in the modifications introduced into these effects by the factor of individual ' constitution.' This identity of effects, indeed, as between the responses of plant and animal, is so deep and so extended, that it is to be anticipated that as several of the obscure problems of animal physiology have already been found elucidated by means of these researches carried out on plants, so others will be found capable of explanation by similar means in the near future. In conclusion, I wish to say that from my assistant, Mr. J. Roy, and my pupils, Messrs. A. C. Basu, S. C. Acharya, S. Chakravarty, N. Roy, and S. Gosvvami, I have received able assistance at various periods during the course of these long and extended investigations. J. C. BOSE. Presidency College, Calcutta : July 1905. CONTENTS PART I.— SIMPLE RESPONSE CHAPTER I THE PLANT AS A MACHINE Responsive movements in plants— Work done by plant — Plant as a machine • — Indicator-diagrams — Physiological response-curves — Pulse-records — Cardiagrams — Modification of pulse by poison and other agencies — Automatic response in plants — Optical Lever Recorder — Effect of external agencies on automatic pulse-beat in plants .... CHAPTER n MECHANICAL RESPONSE TO STIMULUS Molecular derangement caused by stimukis — Expression in change of form, contraction — Mechanical model — Myograph — Response by differential contraction in pulvinated plant-organs — Longitudinal response in plants — Response of plant to all forms of stimulus — Plant chamber — I'ractic- able forms of graduated stimulus — Electro-thermic stimulator — Stimula- tion by condenser discharge — Response-recorder — Advantage of counter- poise— Response of Biophytitvi to thermal stimulation — Response to condenser discharge — Absolute measurements of motile effect and of work performed — Effect of load — Definite determination of threshold of response — Determination of variation of excitability by measurement of minimally effective stimulus ........ CHAPTER HI ON THE UNIVERSALITY OF SENSITIVENESS IN PLANTS AS DEMONSTRATED 15V MEANS OF ELECTRICAL RESPONSE Arbitrary classification of plants into sensitive and ordinary — Method of electro-motive variation for detecting state of excitation — Hydraulic model — Excitation of vegetable tissue, like that of animal tissue, induces galvanometric negativity — Methods of direct and transmitted excitation — Electrical and mechanical response alike record molecular derange- ment and recovery — Similarities in simultaneous record of mechanical PLANT RESPONSE and electrical response — True excitation has a concomitant negative turgidity-variation, negative mechanical response or fall, and galvano- metric negativity — These are true physiological responses, and are abolished at death — Abnormal positive mechanical and electrical responses brought about by positive turgidity-variation— Direct and indirect effects of stimulation — Discrimination of differences of excit- ability- by electric test — Excitability of plant-tissues in general — Re- sponsive power characteristic of matter ...... 29 CHAPTER IV ON CONDITIONS FAVOURABLE TO THE CONSPICUOUS EXHIBITION OF MECHANICAL RESPONSE Differences of degree of motile sensibility in sensitive plants so called — Response of anisotropic organ brought about by differential contraction — Production of response by artificial variation of turgidily — Variation and counter-variation of turgescence, causing two opposite responsive movements — Differences between hydrostatic and true excitatory effects — Distinction of plants as ordinary and sensitive, arbitrary — Sensitive plants may be excited, yet give no mechanical response — Certain con- ditions necessary to exhibition of differential response — Balanced action as result of diffuse stimulus on radial organ — Slight differential contraction of pulvinus magnified by long petiolar index 43 CHAPTER V MECHANICAL RESPONSE IN ORDINARY LEAVES Pulvinoid and pulvinus — Demonstration of mechanical response in ordinary leaves — Response of Ariocgt-pus similar to that of Biophyttim — Response to stimulus, even in old tissues, by expulsion of water — Localisation of motile organ in ordinary leaves — Conducting properties of various tissues — Lamina is not the perceptive organ —Response in ordinary leaves, though sluggish, yet comparable in extent to that of Mimosa —Peculiar phenomenon of fatigue-reversal seen in Mimosa observed also in ordinary plants — Periodic reversals ......... 53 CHAPTER VI LONGITUDINAL RESPONSE OF RADIAL ORGANS Absence of lateral response movements in radial organs due to mutually antagonistic effects of equal contractions of diametrically opposite sides — Lateral response in radial stem of Walnut under unilateral stimulation — Also in pistil of i1///M— Diffuse stimulation of radial organ causes longitudinal contraction — The ' Kunchangraph ' — Longitudinal contrac- tion of stamens of Cyiiereie not unique — Similar longitudinal responses CONTENTS obtained with stems, roots, tendrils, petioles, stamens, and styles of ordinary plants— Also in fungi — Responsive contraction in Pasxiflora, comparable in extent with that in Cynerea — Longitudinal response in plants modified by the physiological variations due to age, season, and chemical agencies ....... . . 66 CHAPTER VII RESPONSIVE CURVATURE OF MOLECULARLY ANISOTROPIC ORGAN Molecular anisotropy artificially induced by one-sided cooling — Cooled side less responsive— Diffuse stimulation causes concavity of the uncooled, that being relatively the more excitable— Local fatigue diminishes excit- ability— Diffuse stimulation now causes concavity of the unstrained side — Similar anisotropy induced in plagiotropic organs, by unilateral action of light — The lower or shaded side of such organs relatively more excit- able—Diffuse stimulation causes current of response from lower to upper, and also concavity of lower half — Responses of plagiotropic Cttcurhita and Convolvulus — Differences in excitabilities of outer and inner surfaces of tubular organ — Complex response due to successive excitations of two antagonistic halves of an anisotropic organ — Response of spiral tendrils by uncurling— Response in certain cases by contraction of the spiral or curling — Writhing movement in spiral tendril under strong stimulation . 82 CHAPTER VIII RELATION BETWEEN STIMULUS AND RESPONSE Ineffective stimulus becomes effective by repetition— Two types of response in contractile animal tissues, cardiac and skeletal— Response of cardiac muscle on 'all or none' principle; parallel case in Biophytum—\n skeletal muscle, increasing stimulus causes increasing response, which tends to reach a limit — Parallel results in longitudinal and electrical response of plants — Effect of superposition of stimuli — Tetanus . . 94 PART II.— MODIFICATION OF RESPOx\SE UNDER VARIOUS CONDITIONS CHAPTER IX ON THE UNIFORM, FATIGUE, AND STAIRCASE EFFECTS IN RESPONSE Uniform response in plants— Staircase effect — Fatigue due to molecular strain — Fatigue in plant- responses — Periodic fatigue — Fatigue under continuous stimulation — Explanation of anomalous erection of leaf of PLANT RESPONSE Mimosa under continuous stimulation— Conductivity and excitability of tissue diminished through incomplete protoplasmic recovery — Relatively greater fatigue in a motile than conducting organ — Disappearance of the motile excitability earlier than conductivity — Refractory period — Absence of responsive effect when stimulus falls williin refractory period . .103 CHAPTER X THEORIES CONCERNING DIFFERENT TYPES OF RESPONSE The chemical theory of response — Insufficiency of the theory of assimilation and dissimilation to explain fatigue and staircase effects — Similar responsive effects seen in inorganic substances — Molecular theory — When molecular recovery is complete, responses uniform : when incom- plete, fatigue brought about by residual strain — Fatigue under con- tinuous stimulation, in inorganic substance, in plant, and in muscle — Staircase effect brought about by increased molecular mobility : examples seen in inorganic substance, and in living tissues— No sharp line of demarcation in the borderland between physical and chemical pheno- mena —Molecular changes attended by changes of chemical activity — Uneijual molecular strain gives rise to a secondary series of chemical actions — Volta-chemical effect and by-products — Supposition tliat re- sponse always disproportionately larger than stimulus, not justified — Existence of three types : (i) response proportionate to stimulus; (2) response disproportionately greater than stimulus; (3) response dis- proportionately less than stimulus — Instances of stimulus partially held latent : staircase and additive effects ; multiple response ; renewed growth ............ CHAPTER XI EFFECT OF AN.ESTHETICS, POISONS AND OTHER CHEMICAL REAGENTS ON LONGITUDINAL RESPONSE Response modified by physiological change — Carbonic acid causes depression, and transitory exaltation as after-effect — Gradual abolition of response in hydrogen and restoration by access of air — Chemical agents cause con- traction or relaxation of plant-tissue — Effect of alcohol causing temporary exaltation of response followed by depression and protracted period of recovery — Ether causes relaxation and temporary depression of response — Explanation of anomalous action of ether on stimulated Mimosa leaf — Abolition of response by hydrochloric acid — Response restored by timely application of ammonia — Abolition of response by poisonous reagent — Similarity of effect of chemical agents on the response of animal and vegetable tissues COxXTEXTS XV CHAPTER XII EFFECT OF TEMPERATURE Temperatures optimum, maximum, and minimum — Diminution of electrical response by cooling — Temporary or permanent abolition of response due to cold — Characteristic differences exhibited by different species- Mechanical response of Biophytinn and autonomous response of Desmodmm arrested by cold — Prolongation of latent period — Diminution of longitudinal mechanical response by cold— Diminution of electrical response of plants by rise of temperature— Similar diminution seen in longitudinal mechanical response — Increase of excitability due to cyclic variation of temperature ......... 159 CHAPTER XIII ON THE DEATH-SPASM IX PLANTS Difficulty of determining exact moment of death — Various post-mortem symptoms afford no immediate indication — Ideal methods for determina- tion of death-point — Realised in four different ways : [a) Determination by electrical method— (A) Determination by spasmodic lateral movement at moment of death — Experiments with Mimosa — Death-contraction a true physiological response— Continuity of fatigue and death— Death- point earlier in young tissues — Composite spasmodic movement — (/'') Determination of death-point in tendril of PassiJJora, by sudden move- ment of uncurling— () by rise of temperature — (c) by fatigue — {d) by anesthetics — Variation of receptive excitability by ether — Conductivity versus excitability — Abolition of motile excitability without abolition of conductivity — Hydro-mechanical theory of transmission of stimulus untenable CHAPTER XIX ON EL.ECTROTONUS The anode acts as a block to the transmission of stimulus— Opposite effect of kathode —Experiments on Biophytum, showing variations of con- ductivity by anode and kathode respectively — Experiments on I\Ii?nosa, showing increase of motile excitability at or near the kathode, and diminution of motile excitability at or near the anode - Curious ' develop- ment ' of response, near the kathode ....... CHAPTER XX ON THE VELOCITY OF TRANSMISSION OF EXCITATORY WAVES IN PLANTS Difficulties in accurate determination of velocity of transmission, due to unknown variations of excitability arising from injury, and variations of conductivity through fatigue — A perfect method of obtaining accurate and consistent results — Relative advantages of studying conduction in plants as compared with animals — Determinations of velocity of trans- mission in centripetal and centrifugal directions — Preferential conductivity in centrifugal direction — Diminution of conductivity and excitability by fatigue — Within a certain critical interval, organ ' refractory ' to further stimulus — Increased velocity of transmission with increasing stimulus — Measurement of diminution of conductivity by cold — Fibro-vascular elements the best conducting channels — Conductivity lengthwise greater than crosswise — Electric mode of determination of velocity of trans- mission— Indifferent parenchymatous tissues practically not transmitters of excitation — Comparative tables showing velocity of transmission in various plant and animal tissues 238 CHAPTER XXI ON DETECTION OF EXCITATORY PULSE DURING TRANSIT BY ELECTROTACTILE AND ELECTROMOTIVE METHODS Pfeffer's experiment on expulsion of water from excited cells — Author's experiment on a delicate method of detecting excitatory expulsion of cell- sap^Chemical method of determining velocity of transmission of excita- tion— Electrotactile detector — Demonstration of passage of excitatory PLANT RESPONSE I'AGE contractile wave by means of electrotactile method — Determination of velocity of transmission of excitation in ordinary plants by electromotive method — Excitatory versus hydro-mechanical movement of water . -254 CHAPTER XXII THE LATENT PERIOD AND REFRACTORY PERIOD The determination of the latent period in Mimosa — Experimental arrange- ments for obtaining automatic record — Prolongation of latent period by cold— Spark-record for determination of latent period— Prolongation of latent period by fatigue — Sluggishness of the response of Pliilanthus urinaria, also long latent period and very protracted period of recovery ■ — Latent period reduced under strong stimulation — Response in Biophytiim on the ' all or none ' principle — Definite value of effective stimulus — Phenomenon of refractory period in Biophytiim — Parallelism of responses in Biophytiim and in cardiac muscle — Additive effects — Inappropriateness of term ' refractory period ' — Energy in excess of effective stimulus held latent for subsequent manifestation . . . 264 PART IV.— MULTIPLE AND AUTONOMOUS RESPONSE CHAPTER XXIII ON MULTIPLE RESPONSE Multiple electromotive responses due to a single strong stimulus — Multiple electrotactile responses — Multiple mechanical responses in Biophytiim — Cyclic variations in multiple responses — Multiple retinal excitations — Intermittent pulse in man and plant — Semi-automatism — Continuity of multiple and automatic response — Conversion of Biophytiim into auto- matically responding plant ; conversion of Desviodiiim into ordinarily responding plant — Similar polar effects of current in Biophytiim and in Desmodiiim leaflet at standstill — Moderate stimulus in Biophytiim and in Desmodium at standstill produces single response ; and strong stimulus, multiple response 279 CHAPTER XXIV AN INQUIRY INTO THE CAUSES OF AUTONOMOUS MOVEMENTS Production of pulsatory movements as after-effect of energy absorbed — Physical analogue -Localisation of seat of automatic excitation in Des- modium— Demonstration of multiple response to a constant stimulus : (I) Chemical— (2) Electrical— (3) Stimulus of light— Multiple reiix»nse CONTENTS to constant stimulus of light, in : {a) retina — (/>) Biophytitiii—(c) Des- modiuin — (4) Thermal — Induction of automatism in Biophytum at favourable temperature — (5) Of internal hydrostatic pressure — Absorp- tion of external energy and its absorption by the plant in latent form — True meaning of ' tonic ' condition — Cause of rhythmicity — After-effect, and its relative persistence ......... 295 CHAPTER XXV INFLUENCE OF VARIOUS CHEMICAL REAGENTS ON THE AUTONOMOUS RESPONSE OF DESMODIUM GYRANS The recorder and experimental chamber — Absolute measurement of period and amplitude of /5(,'jw£;f///^/;;.oscillation — Responsive significance of up and down movements deduced from («) analogy with response of Mimosa ; {b) test of increased internal hydrostatic pressure — ' Systolic ' contraction and 'diastolic' expansion oi DesmodhDw^wWixwx's, — Mode of application of chemical reagents — Action of chemical reagents modified by : tonic condition of plants ; strength of solution ; and duration of application — Effect of anaesthetics — Effect of alcohol — Effect of carbonic acid — Effects of ammonia and of carbon disulphide — Effect of copper sulphate solution, either when applied externally, direct on the pulvinus, or internally —Spark-record of Z?^^wc>rt'///w-pulsation .... 315 CHAPTER XXVI EFFECTS OF TEMPERATURE ON AUTONOMOUS RESPONSES Increase of frequency and diminution of amplitude of pulsation with rising temperature— Converse effect of fall of temperature - Similar effect in cardiac pulsation — Effect of the reduction of temperature to the thermo- tonic minimum — Explanation of diminution of amplitude of pulsation with rise of temperature — Anomalous use of the word ' relaxation ' — Simple versus additive character of individual pulsation . . , 329 CHAPTER XXVH SIMILARITIES OF RHYTHMIC RESPONSE IN VEGETABLE AND ANIMAL TISSUES The similarities, in their fundamental characteristics, of rhythmic tissues, animal and vegetable: (i) In responses — (2) In possession of long re- fractory periods — (3) In incapability of tetanus — Theories regarding the causation of heart-beat — The similarities of rhythmic tissues, animal and vegetable, as seen in : (i) The effects of internal hydrostatic pressure — (2) The effects of variation of temperature — (3) The periodic groupings PLANT RESPONSE of response— (4) The effect of barium salt— (5) The antagonistic actions of acid and alkali — Identity of rhythmic phenomena in animal and vegetable tissues .......... 344 PART v.— ASCENT OF SAP CHAPTER XXVIII SUCTIONAL RESPONSE AND ASCENT OF SAP Inadequacy of existing theories of ascent of sap — General considerations regarding cellular activity and resultant propulsion of water — The Shoshungraph — Balanced Shoshungraph for determining variations of suction — Hydrostatic and Hydraulic Methods of Balance . . . 359 CHAPTER XXIX MODIFICATION OF SUCTIONAL RESPONSE Effect of temperature on suction by three methods of inquiry: (i) Un- balanced method of Shoshungraph : {a) Action of cold — (d) Action of moderate rise of temperature — (2) Method of Hydrostatic Balance : (a) Action of cold — Reversal of normal direction of flow — {/>) Action of warm water — (3) Method of Hydraulic Balance — {a) Action of cold — (/>) Effect of warm water — Explanation of suction when the root is killed by boiling water — Stimulation renews suctional activity in plant whose suction has come to a standstill — Osmotic versus excitatory action — Abolition of suction by poison — Suctional activity continued until whole plant is killed by poison ■ . . . 372 CHAPTER XXX THE PHENOMENON OF PROPULSION OF SAP AND ITS VARIOUS EFFECTS r The mechanics of the ascent of sap : {a) Uni-directioned flow — (/') Initiation of multiple rhythmic excitations — Connection between conduction of excitation and conduction of sap— Rapidity of ascent of sap accounted for by stimulatory action — Positive and negative pressures due to one cause — (i) Positive pressure — (2) Negative pressure — (3) Irregular variations of pressure — Direct conduction and conduction by relays — Excretion of water — Excretion of nectar — Translocation of organic food- substances — Mechanical response to suctional activity — Effect of warmth — E.ftect of cold — Explanation of the drooping of leaves during frost — Explanation of response and recovery — Antagonistic actions of internal energy and external stimulus CONTENTS PART VI.— GROWTH CHAPTER XXXI THE RECORD OF GROWTH-RESPONSE I'AGE The simple Crescograph— The Balanced Crescograph— Rhythmic growth- response — Growth-response and excitatory response — Law of direct and indirect effects of excitation — Positive turgidity- variation as indirect effect of excitation — Mechanical test — Significance of ' inner stimuli ' . . 409 CHAPTER XXXH THE EFFECTS ON GROWTH OF INTERNAL ENERGY AND EXTERNAL STIMULUS Characteristics common to growth and to other forms of rhythmic response : (i) Periodic groupings — (2) Effect of external stimulus in renewal of growth when at temporary standstill — (3) Renewal of growth-pulsation by positive turgidity-variation — (4) Effect of increased internal hydro- static pressure— (5) Effect of ascent of sap on growth — Effect of tempera- ture on growth — Comparison of various types of multiple response — Effect of external tension on growth — Effect of direct application of stimulus on the growing region — Similarities between motile and growth responses — Direct and indirect effects of stimulus, and laws of growth . 424 CHAPTER XXXni ON THE RELATION BETWEEN TEMPERATURE AND GROWTH, AND THE ACCURATE DETERMINATION OF OPTIMUM AND MAXIMUM POINTS General consideration of difficulties of accurate determination of effects of temperature on growth— Four accurate methods : (i) Method of discon- tinuous observations— Accurate regulation of temperature by electrolytic rheostat — (2) Method of continuous observations — Thermo-crcscent curve — Determination of the optimum point — (3) Method of balance - (4) Method of excitatory response — Translocation of the optimum point 441 CHAPTER XXXIV ON AN ATTEMPT TO DETECT AND MEASURE LATENT STIMULUS, AND ON THE STUDY OF PERIODIC AFTER-EFFECTS Positive and negative after-effects — Extreme delicacy of the Method of Balance —Detection of absorbed stimulus by negative after-effect — PLANT RESPONSE Constancy of sum of direct and indirect after-effects — Latent component almost vanishing above the optimum— Variation of receptivity — Direct and indirect response of plant in sub-tonic condition — Table showing direct and indirect effects at different temperatures — Is the change induced by stimulus always of an explosive chemical character ? — Rela- tion between stimulus and response in different tonic conditions— After- effect— Factors which determine periodic after-effects: (i) Stimulus of light — (2) Temperature— (3) Chemical stimulus — (4) Turgidity — Con- tinuous photographic record of the pulsations of Desnwdiiim — Record of periodic variation of rate of growth— Continuous photographic record of periodic variations of transpiration — Continuous photographic record of the variation of the rate of growth — Annual rings and seasonal periodicity 456 CHAPTER XXXV AN INVESTIGATION INTO THE DIFFERENT EFFECTS OF DRUGS ON PLANTS OF DIFFERENT 'CONSTITUTIONS' General consideration of the problem — ' Constitution ' and the elements which determine it — Methods of investigation — Action of carbonic acid gas — Action of ether — Effect of solution of sodium carbonate — Effect of solution of sugar — Effect of alcohol — Effect of acids— PLffect of alkali — Antagonistic action of alkalis and acids — Action of strong solution of sodium chloride — Effect of poisonous solution of copper sulphate — Opposite effects of the same dose on different constitutions— Opposite effects of large and small doses .......'. 4 PART VII.— GEOTROPISM, CHEMOTROPISM, AND GALVANOTROPISM CHAPTER XXXVI THE RESPONSIVE CURVATURES CAUSED BY GRAVITY. NEGATIVE GEOTROPISM Statement of the problem of apogeotropic response — Mode in which stimu- lation is brought about : radial-pressure theory, and theory of statoliths — Mechanics of responsive movement — Experiment demonstrating re- sponsive curvature as brought ab.out by unilateral pressure of particles — Record of curvature induced by gravitation — Record of different rates of curvature when specimen is held at angles of 45° and 135° to the vertical — Determination of the true character of apogeotropic response — Responsive curvature of acellular organs— Curvature of grass haulm under gravity — Growth of grass haulm on a klinostat .... 493 CONTENTS CHAPTER XXXVII THE RESPONSIVE PECULIARITIES OF THE TIPS OF GROWING ORGANS I'AGE Difference between shoot and root in their response to stimulus of gravity — Difference in character of response between tip and growing region of root — Scope of the investigation — Electrical investigation— Responsive results of: i. Longitudinal transmission of effect of stimulus from tip ; (a) Moderate unilateral stimulation ; (/;) effect of stronger unilateral stimulation — 2. Direct unilateral stimulation of growing region — Moderately strong stimulus — 3. Transverse transmission of effect of stimulus ; {a) moderate stimulation ; (6) stronger stimulation- Mechanical response inferred from observed electrical response — Tabular statement 512 CHAPTER XXXVIII INQUIRY INTO THE LAWS OF RESPONSIVE GROWTH- CURVATURES Scope of the investigation : i. Mechanical response to unilateral stimula- tionof the tips of shoot and root : (a) Moderate stimulus — (A) Stronger stimulation — 2. Effect of unilateral stimulus, applied at the responding growing region: (a) Moderate stimulus— (/6) Strong or long-continued stimulus — Experiments on the direct and indirect effects of stimulus on Mimosa : {a) Direct stimulation — (d) Indirect stimulation, longitudinal transmission — (c) Indirect stimulation, transverse transmission — The curious response of A riscswa — Table showing responsive effects common to pulvini, pulvinoids, and growing organs — Laws of responsive growth- curvature 524 CHAPTER XXXIX INQUIRY INTO POSITIVE GEOTROPISM No specific difference as regards their responses, between shoot and root — Darwinian curvature — Localisation of geotropic sensibility at the root- tip — Experiments as to whether amputation of root-tip abolishes excitability — The tip of the root the organ of gravi-perception — The perceptive z'ersi/s the responding organ — True perceptive region . . 536 CHAPTER XL ON CHEMO-TROPISM AND GALVANO-TROPISM General difficulties of the investigation — How to overcome these ditficuUies — Three distinct methods of testing results : ( i ) by variation of longitudinal dv PLANT RESPONSE PAGE growth ; (2) by responsive movement of pulvinus ; and (3) by growth- curvature— Method of application of chemical reagent — Effect of alkali — Effect of acid — Effect of copper sulphate — Action of sugar solution — Chemo-tactic movements — Explanation of anomalous osmotic or plas- molytic action— Excitatory versus plasmolytic reaction in pulvinus of Mimosa : (i) Favourable tonic condition — (2) Ordinary tonic condition — Polar effects of currents inducing growth-curvatures— Localised polar effects on pulvinus — Anodic and kathodic effects on longitudinal growth — Generalised law of polar excitation in plants — Gal vano-tropic response — The indirect effect of polar excitation — The effect on growth of ' electrification ' of soil 546 PART VIII.— HELIOTROPISM CHAPTER XLI FUNDAMENTAL RESPONSIVE ACTION OF PLANT-TISSUES TO STIMULUS OF LIGHT Diversity of movements induced by light — Differentiation of responsive movements — Action of light on tissues in sub-tonic condition — Effect of light on pulvinated organs — Effect of diffuse stimulation of light on non-growing radial organs — Retarding effect of light on longitudinal growth — Phenomenon of oscillation under long-continued stimulation — Similarity of responsive reaction under light and under other forms of stimulation ........... 565 CHAPTER XLII POSITIVE HELIOTROPISM Introduction — Theory of de Candolle — Inadequacy of de Candolle's theory — Definition of terms positive and negative — Darwin's theory of modified circumnutation — Response of terminal leaflet ol Desmodium — ■ Extreme sensitiveness of some plant-organs to light — Merging of multiple in continuous response — Orientation induced by light — The perceptive region in the terminal leaflet of Desmodium — Heliotropic response in radial organ — Magnetically controlled recorder — Heliotropic response of hypocotyl of Sinapis — Recovery and theory of recti-petality. 579 CHAPTER XLHI NEGATIVE HELIOTROPISM Incomplete parallelism between actions of light and of gravitation — Theoretical considerations — Recording microscope — Negative helio- CONTENTS tropic curvature induced by stimulation of the tips of root and shoot — Intermediate phases between positive and negative heliotropic response : {a) neutralisation by transverse transmission ; {6) neutralisation by transverse transmission, with multiple response — Localised sensitiveness to light and transmission of excitatory effect — Negative heliotropism of a radial organ — Gradual transition from positive to negative, through intermediate phase of neutrality — Apparent heliotropic insensitiveness of certain tendrils — Negative heliotropism of tendril of V///s . . . 597 CHAPTER XLIV EFFECT OF INVISIBLE RADIATION AND EMANATIONS Effect of temperature and its variations — Demonstration of fundamental effect of thermal radiation on growth — Response to successive uniform stimuli of thermal radiation — Effect of continuous unilateral stimulation — Effect of electrical waves on growth— Response of Mimosa to electric radiation — Action of high frequency Tesla current .... 614 CHAPTER XLV ON PHOTONASTIC PHENOMENA AND ON DIURNAL SLEEP Photonasty and para-heliotropism — Response of Tropieolttm iiiajits — Re- sponses of plagiotropic stems : {a) Mimosa — {b) Ipomaa — (c) Cuciirbiia — Daily periodic movements of plagiotropic stems — Responsive movements of pulvinated organs — Pulvinated organs showing positive heliotropic movement: {a) Responseof terminal leaflet of Z)fj-w(7) Positive response — Responsive action under stimulus of gravity — Heliotropic action in radial organs — Heliotropic action in plagiotropic and dorsi-ventral organs — Phototactic movements — Nyctitropic movements ..... 725 CHAPTER LII ON PHYSIOLOGICAL RESPONSE, AND ITS CONTINUITY IN PLANT AND ANIMAL Vitalism -Fundamental unity of physiological response in plant and animal — Theory of Darwin — Variation as induced by external forces . . 740 CLASSIFIED LIST OF EXPERIMENTS 755 INDEX 765 EBRATUM Page 409, line i of analytical contents, y^r Growth-Recorder ?Ya<)' Crescograph. ILLUSTRATIONS FIG. I'AGE 1. Record of Healthy Adult and Senile Human Pulse (Broadbent) . . 3 2. Effect of Muscarin in arresting Pulsation of Frog's Ventricle (Cashing) 4 3. Record of Human Pulse (Broadbent) ...... 4 4. Demonstration Optical Pulse- Recorder 7 5. Death of Plant, and Arrest of Pulsation, by Poison .... 8 6. Death, and Arrest of Pulsation, in Leaflet of Dcsinodiuiii by Strong Electric Shock 8 7. Response of India-rubber 12 8. Mechanical Lever Recorder 12 9. Series of Contractile Responses in Muscle 13 10. Photographic Record of Longitudinal Contractile Response in ordinary Stamens {Browtiea ariza) . . . . . . . 13 11. Differential Lateral Response of Compound Strip .... 13 12. Plant Chamber and Recorder 16 13. The Electro-thermic Stimulator 17 14. Diagram of Connections for Stimulation by Condenser Discharge . 18 15. Photographic Record of Response and Recovery of Mimosa, taken on a slowly moving drum 21 16. Photographic Record of Response in different specimen, taken on a faster-moving drum 21 17. Response of .5/'//cw 285 1 18. Multiple Response in i^/fj/z^j/z/w 285 119. Multiple Response in Biophylum, showing Cyclic Groupings of Amplitude and Period ......... 286 ILLUSTRATIONS XXxiii FIG. PAGE 1 20. Multiple Response in Biophyttim, showing Cyclic Groupings . . 286 121. Intermittent Human Pulse (Broadbent) 288 122. Intemiittence in Pulsation of j'?/(7//!j//?/;w 289 123. Multiple Response of Biophytum under the Continuous Action of Light 303 124. Induction of Autonomous Response in Biophytum, at Moderately High Temperature of 35° C. 305 125. Experimental Apparatus for Making Records of Pulsation q{ Desvio- diwn . . . . . . . . . . . . 316 126. Photographic Record of Pulsation of Z)^j-;«^fl'/«w . . . -317 127. Photographic Record of Uniform Pulsations in Z?('.fW(?(^!'/«w . . . 318 128. Displacement of Mean Position of Vibration of DesinodiiiDi Leaflet by Increased Internal Hydrostatic Pressure 320 129. Method of Application of Chemical Agent to Cut End of Petiole . 321 130. Photographic Record of Effect of Ether Vapour, Large Dose . . 324 131. Photographic Record of Effect of Alcohol 325 132. Photographic Record of Effect of Carbonic Acid Gas . . . 325 133. Photographic Record of Effect of Copper Sulphate Solution Applied on the Pulvinus . . . . . . . . . . 326 134. Spark-record of Single Pulsation in Leaflet of Z>e.rw(?<^/«/;;/ . . 327 135. Photographic Records of Autonomous Pulsations in Desmodiuiii, showing Increase of Amplitude and Decrease of Frequency, with Lowering of Temperature 332 136. Effect of Lowering of Temperature in Producing Increase of Ampli- tude and Decrease of Frequency in Pulsation of Frog's Heart . 333 137. Photographic Record of Pulsations of Desinodiitin during Continuous Rise of Temperature 333 138. Record of Pulsations of Z>^jw(7^ww ..... 350 1 50. Simple Alternation of Pulsation in Frog's Heart (Pembrey and Phillips) 350 b xxxiv PLANT RESPONSE FIG. PAGE 151. Effect of Barium Chloride Solution on Z)^.w/^rf/«w . . . . 351 152. Arrest of Beat of Ventricle of Frog at Diastole by Application of Acid 351 153. Systolic Arrest of Heart-beat by Dilute NaHO Solution (Gaskell) . 352 1 54. Arrest of Desinodium Pulsation at ' Diastole ' by Application of Acid 352 155. Arrest of Pulsation of Desnioditiin at 'Systole' by Application of Dilute Alkali 353 156. Diagrammatic Representation of the Shoshungraph . . . . 365 157. Photograph of Shoshungraph • . . . 370 158. Effect of Cold on Suction 374 159. Curve showing Normal Suction at 23° C, Increased Suction at 35° C, and the After-effect persisting on Return to Normal Tem- perature ............ 375 160. Method of Hydrostatic Balance 375 161. Record obtained by Method of Hydrostatic Balance of Successive Applications of Cold and Warm Water 378 162. Record, obtained by Method of Hydraulic Balance, of Successive Effects of Cold and Warm Water 380 163. Effect of Strong KNO3 Solution 3S4 164. Effect of Strong NaCl Solution 384 165. Effect of Copper Sulphate Solution 386 166. Record showing Recovery to be Hastened by the Increase of Internal Activity which is caused by Application of Warm Water to the Roots ............ 401 167. Diagrammatic Representation of Balanced Crescograph . . . 414 168. Complete Apparatus for Crescographic Record under Ordinary and Balanced Conditions 416 169. Multiple Growth-responses (Peduncle of Crocus) . . . . 417 1 70. Responses of Leaf of Artocarpits to Thermal Stimulation . . 420 171. Renewal of Growth-pulsation by Thermal Stimulus in Tamariudus indica originally at Standstill ........ 425 172. Initiation of Erectile Response in Leaf by Supply of Water to partially Drought-rigored Mimosa ........ 426 173. Initiation of Growth-pulsation by Small Supply of Water to Drought-rigored Seedling of Citciirbita . . . . . . 426 174. Curve showing Relation between Internal Hydrostatic Pressure and Rate of Growth ( Ci-imini Lily) ....... 429 175. Photographic Record showing the Slow Pulsations of Large Amplitude of Dcsinodiujii Leaflet at 30° C. to become very much Quickened and Reduced in Amphtude at 42° C 431 176. Growth-pulsation seen in Seedling of i^ir/j-rtw 432 177. Photographic Record of Responses of Mature Style of Datura alba to External Thermal Stimulus 434 1 78. Photographic Record of Responses of Style of Datura alba in which Growth had come to a Temporary Stop 435 179. Photographic Record of Response of Growing Style oi Datura alba to External Stimulus , . . , 436 ILLUSTRATIONS XXXV FIG. I-AGE 1 80. Balanced Record of Response in Growing Peduncle of Encharis Lily to Electrical Stimulation 436 181. Semicircular Electrolytic Rheostat interposed in Heating Cir- cuit 443 182. Record of Growth in Crinum at Temperature of 34° C. and 35° C 445 183. Thermo-crescent Curve of Growth in Criitiiin Lily under Continu- ously Increasing Temperature 447 184. Curve showing Relation between Temperature and Rate of Growth, as deduced from the Thermo-crescent Curve .... 449 185. Series of Responses of Growing Organ of Crinum Lily, taken under Balanced Conditions at Three Different Temperatures . . . 460 186. Curve showing the Relation between Stimulus and Response in the same Organ, under the two different Tonic Conditions of 30° C. (upper curve) and 37° C. (lower curve) 467 187. Continuous Photographic Record of Autonomous Pulsation of Des- modiion gyraiis from 6 p.m. to 6 a.m. . . . . . . 470 188. Hydrometric Apparatus for 'Recording Continuous Variation of Rate of Growth 471 189. Photographic Record showing Variation of Rate of Transpiration in Cticui-bita, from 3 p.m. to 12 p. m 472 190. Continuous Photographic Record of Variation of Rate of Growth in Four Days' Old Seedling of Oryza saliva, from 3 p.m. till 9 a.m., that is during Eighteen Hours 473 191. Continuous Photographic Record of Variation of Rate of Growth in Seedling of Tamarindiis indica, a Fortnight Old, from 3 p.m. to 3 A.M 474 192. Effect of Carbonic Acid Gas on Growth 480 193. Balanced Records of Effect of Ether on Growth . . . . . 481 194. Excitatory Effect of Dilute Solution of Sodium Carbonate on Growth . . . . . . . . . . .481 195. Acceleration of Growth by Application of Solution of Sugar . . 482 196. Spasmodic Alternations of Growth under Alcohol .... 483 197. Unbalanced Record showing Action of Acid in Causing Relaxation and Ultimate Arrest of Growth 483 198. Unbalanced Record showing the Action of Alkali, and the Antago- nistic Action of Subsecjuent Application of Acid .... 484 199. Effect of Strong Solution of NaCl on Rate of Growth, as Modified by Different Constitutions of Specimens 484 200. The Effect of Different Constitutions in Determining the Resistance Offered to Poisons. The Action of 5 per Cent. Solution of Copper Sulphate 487 201. The Effect of Favourable Induced Constitution in Enabling Plant to Shake oft" Result of Toxic Dose of Copper Sulphate . . . . 487 202. Opposite Eftects of Large and Small Doses of Poison . . . 488 203. Diagrammatic Representation showing Difierential Eft'ect of Weight on Lateral Walls of Cells 494 204. Diagrammatic Representation of a Multicellular Organ . . . 495 PLANT RESPONSE FIG. PAGE 205. Diagrammatic Representation of Experiment showing Curvature Induced by Unilateral Pressure Exerted by Particles . . . 497 206. Record of Responsive Curvature induced in Crimim under Experi- mental Conditions shown in fig. 205 498 207. Record of Apogeotropic Response in Scape of Uriclis Lily . . . 500 208. Response Records showing Differences in Rate of Curvature according as Specimen is held at Angles of 45° and 135° . . 501 209. Diagrammatic Representation of Different Positions of a Single Cell, according as the Specimen is held at an Angle of 45° or 135°, showing Consequent Redistribution of Statoliths (after F. Darwin) ........... 502 210. Effect on Apogeotropic Movement of Application of Ice-cold Water to Upper and Lower Surfaces alternately of a Horizontally laid Crinuvir Lily .......... 504 211. Effect on Apogeotropic Movement of Temporary Applications of Cold alternately to Upper and Lower Surfaces of Horizontally laid Scape of Uriclis Lily ........ 505 212. Experimental Connections for obtaining Electrical Response due to Direct and Indirect Effects of Stimulation 515 213. Record of Positive Electrical Variation, indicating Positive Turgidity- Variation (represented by Down Curve), induceci in Growing Region by Moderate Stimulation on same side of Tip . . . 517 214. Record showing Galvanometric Positivity subsequently Neutralised under Transmission of True Excitatory Effect, due to Continuance of Mo.derate Stimulation of the Tip 517 215. Record showing Neutralisation and Reversal of Electrical Response at Responding Region, under Strong Stimulation of Tip . . . 518 216. Record showing Negative Electrical Response represented by Up Curve, indicating Negative Turgidity-Varialion due to Direct Stimulation . , . . . . . , . .518 217. Record showing Positive Electrical Variation indicating Positive Turgidity-Variation of Distal Point, under Moderate Stimulation of Proximal 519 218. The Relative Electrical and Turgidity Variations of two Diametri- ally Opposite Points when Strong and Long-continued Stimulus is applied 521 219. Mechanical Responses of Shoot and of Root to Unilateral Stimulus applied at the Tip 526 220. Mechanical Response of Root of Bindweed to very strong Unilateral Stimulation applied at the Tip 527 221. Mechanical Responses of Peduncle of Crocus and Root of Bind- weed to Unilateral Thermal Stimulation at the Growing Region . 527 222. Diagram showing the various Responsive Effects induced at the Growing Region . ......... 529 223. Experimental Arrangement for obtaining Records on Smoked Drum of Responses given to Direct and Indirect Stimulation by 'L^&i oi Mimosa 530 224. Mechanical Responses of Leaf of i1//wt?j-a .... 531 ILLUSTRATIONS XXXvU KIG. PAGE 225. Erectile Response of Leaf of Mimosa due to Transmission of Indirect Effect to Distal Side, when Proximal is Stimulated . ... 532 226. Curious Response of Ariscema ....... 533 227. Curves showing Effect of Amputation on Rate of Growth and Response in Root of Bindweed 541 228. Response of Leaf of Mimosa in Favourable Tonic Condition to Chemical Stimulus of 3 per Cent. Salt Solution .... 551 229. Response of Leaf of Mimosa in Ordinary Tonic Condition to the Chemical Stimulus of 10 per Cent. Solution of Salt . . . . 552 230. Polar Effects of Currents due to Localised Application on Upper WOii oiVvXvi'nyi's, ol Erythrina iitdica ...... 555 231. Effects of Anode and Kathode on Variation of Rate of Growth in Root of Bindweed exhibited by Balanced Growth-record . . . 557 232. Responsive Curvature in Scape of Crinitm Lily by Unilateral Application of Anode and Kathode 558 233. Effect in Acceleration of Rate of Growth of Seedling of Oryza sativa of Current through the Soil ........ 560 234. Longitudinal Contraction and Retardation of Growth under Light in Hypocotyl of Sinapis nigra ........ 572 235. Balanced Record of Variation of Growth in Flower-bud of Crinum Lily under Diffuse Stimulation of Light . . . . . . 574 236. Oscillatory Response of Arsenic acted on Continuously by Hertzian Radiation 575 237. Multiple Response to Light of Terminal Leaflet of Desmodiutn . . 584 238. Response of Terminal Leaflet of Desmodium to Strong Light from Above 586 239. Response of Terminal Leaflet of Desmodium to Sunlight acting from Below 587 240. Diagrammatic Representation oi the Magnetically Controlled Recorder 389 241. Heliotropic Chamber and Magnetically Controlled Recorder . . 591 242. Heliotropic Response of Sinapis 593 243. Heliotropic Response of Sinapis to Sunlight 593 244. Microscope Recorder 599 245. Record of Response of Root of 5ma//j- «?^/-fl 601 246. Positive Heliotropic Movement of Terminal Leaflet of Desmodium Converted by Strong and too Long-continued Stimulus of Light into Oscillatory Movement ........ 604 247. Response of Hypocotyl of Sinapis nigra 609 248. Responses to Successive Uniform Stimuli of Thermal Radiation in Pistil of yy?