PREFACE

I have in the present work put in a connected and a more complete form results, some of which have been published in the following Papers:

These investigations were commenced in India, and I take this opportunity to express my grateful acknowledgments to the Managers of the Royal Institution, for the facilities offered me to complete them at the Davy-Faraday Laboratory.

J. C. Bose.

Davy-Faraday Laboratory, Royal Institution,
London: May 1902.

CONTENTS

[CHAPTER I]
THE MECHANICAL RESPONSE OF LIVING SUBSTANCES		PAGE
Mechanical response—Different kinds of stimuli—Myograph—Characteristics of response-curve: period, amplitude, form—Modification of response-curves[1]
[CHAPTER II]
ELECTRIC RESPONSE
Conditions for obtaining electric response—Method of injury—Current of injury—Injured end, cuproid: uninjured, zincoid—Current of response in nerve from more excited to less excited—Difficulties of present nomenclature—Electric recorder—Two types of response, positive and negative—Universal applicability of electric mode of response—Electric response a measure of physiological activity—Electric response in plants[5]
[CHAPTER III]
ELECTRIC RESPONSE IN PLANTS—METHOD OF NEGATIVE VARIATION
Negative variation—Response recorder—Photographic recorder—Compensator—Means of graduating intensity of stimulus—Spring-tapper and torsional vibrator—Intensity of stimulus dependent on amplitude of vibration—Effectiveness of stimulus dependent on rapidity also[17]
[CHAPTER IV]
ELECTRIC RESPONSE IN PLANTS—BLOCK METHOD
Method of block—Advantages of block method—Plant response a physiological phenomenon—Abolition of response by anæsthetics and poisons—Abolition of response when plant is killed by hot water[27]
[CHAPTER V]
PLANT RESPONSE—ON THE EFFECTS OF SINGLE STIMULUS AND OF SUPERPOSED STIMULI
Effect of single stimulus—Superposition of stimuli—Additive effect—Staircase effect—Fatigue—No fatigue when sufficient interval between stimuli—Apparent fatigue when stimulation frequency is increased—Fatigue under continuous stimulation[35]
[CHAPTER VI]
PLANT RESPONSE—ON DIPHASIC VARIATION
Diphasic variation—Positive after-effect and positive response—Radial E.M. variation[44]
[CHAPTER VII]
PLANT RESPONSE—ON THE RELATION BETWEEN STIMULUS AND RESPONSE
Increased response with increasing stimulus—Apparent diminution of response with excessively strong stimulus[51]
[CHAPTER VIII]
PLANT RESPONSE—ON THE INFLUENCE OF TEMPERATURE
Effect of very low temperature—Influence of high temperature—Determination of death-point—Increased response as after-effect of temperature variation—Death of plant and abolition of response by the action of steam[59]
[CHAPTER IX]
PLANT RESPONSE—EFFECT OF ANÆSTHETICS AND POISONS
Effect of anæsthetics, a test of vital character of response—Effect of chloroform—Effect of chloral—Effect of formalin—Method in which response is unaffected by variation of resistance—Advantage of block method—Effect of dose[71]
[CHAPTER X]
RESPONSE IN METALS
Is response found in inorganic substances?—Experiment on tin, block method—Anomalies of existing terminology—Response by method of depression—Response by method of exaltation[81]
[CHAPTER XI]
INORGANIC RESPONSE—MODIFIED APPARATUS TO EXHIBIT RESPONSE IN METALS
Conditions of obtaining quantitative measurements—Modification of the block method—Vibration cell—Application of stimulus—Graduation of the intensity of stimulus—Considerations showing that electric response is due to molecular disturbance—Test experiment—Molecular voltaic cell [91]
[CHAPTER XII]
INORGANIC RESPONSE—METHOD OF ENSURING CONSISTENT RESULTS
Preparation of wire—Effect of single stimulus[100]
[CHAPTER XIII]
INORGANIC RESPONSE—MOLECULAR MOBILITY: ITS INFLUENCE ON RESPONSE
Effects of molecular inertia—Prolongation of period of recovery by overstrain—Molecular model—Reduction of molecular sluggishness attended by quickened recovery and heightened response—Effect of temperature—Modification of latent period and period of recovery by the action of chemical reagents—Diphasic variation[104]
[CHAPTER XIV]
INORGANIC RESPONSE—FATIGUE, STAIRCASE, AND MODIFIED RESPONSE
Fatigue in metals—Fatigue under continuous stimulation—Staircase effect—Reversed responses due to molecular modification in nerve and in metal, and their transformation into normal after continuous stimulation—Increased response after continuous stimulation[118]
[CHAPTER XV]
INORGANIC RESPONSE—RELATION BETWEEN STIMULUS AND RESPONSE—SUPERPOSITION OF STIMULI
Relation between stimulus and response—Magnetic analogue—Increase of response with increasing stimulus—Threshold of response—Superposition of stimuli—Hysteresis[131]
[CHAPTER XVI]
INORGANIC RESPONSE—EFFECT OF CHEMICAL REAGENTS
Action of chemical reagents—Action of stimulants on metals—Action of depressants on metals—Effect of ‘poisons’ on metals—Opposite effect of large and small doses[139]
[CHAPTER XVII]
ON THE STIMULUS OF LIGHT AND RETINAL CURRENTS
Visual impulse: (1) chemical theory; (2) electrical theory—Retinal currents—Normal response positive—Inorganic response under stimulus of light—Typical experiment on the electrical effect induced by light[148]
[CHAPTER XVIII]
INORGANIC RESPONSE—INFLUENCE OF VARIOUS CONDITIONS ON THE RESPONSE TO STIMULUS OF LIGHT
Effect of temperature—Effect of increasing length of exposure—Relation between intensity of light and magnitude of response—After-oscillation—Abnormal effects: (1) preliminary negative twitch; (2) reversal of response; (3) transient positive twitch on cessation of light; (4) decline and reversal—Résumé[158]
[CHAPTER XIX]
VISUAL ANALOGUES
Effect of light of short duration—After-oscillation—Positive and negative after-images—Binocular alternation of vision—Period of alternation modified by physical condition—After-images and their revival—Unconscious visual impression.[170]
[CHAPTER XX]
GENERAL SURVEY AND CONCLUSION		[181]
[INDEX][193]