Chapter I: 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:

'De la Généralité des Phénomènes Moléculaires produits par l'Electricité
sur la matière Inorganique et sur la matière Vivante.' (_Travaux du
Congrès International de Physique._ Paris, 1900.)

'On the Similarity of Effect of Electrical Stimulus on Inorganic and
Living Substances.' (_Report, Bradford Meeting British Association,
1900.--Electrician._)

'Response of Inorganic Matter to Stimulus.' (Friday Evening Discourse,
Royal Institution, May 1901.)

'On Electric Response of Inorganic Substances. Preliminary Notice.'
(Royal Society, June 1901.)

'On Electric Response of Ordinary Plants under Mechanical Stimulus.'
(_Journal Linnean Society_, 1902.)

'Sur la Réponse Electrique dans les Métaux, les Tissus Animaux et
Végétaux.' (Société de Physique, Paris, 1902.)

'On the Electro-Motive Wave accompanying Mechanical Disturbance in
Metals in contact with Electrolyte.' (_Proceedings Royal Society_,
vol. 70.)

'On the Strain Theory of Vision and of Photographic Action.' (_Journal
Royal Photographic Society_, vol. xxvi.)

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