high mag­ni­fi­ca­tion—Automatic record of the rate of growth—​Determination of the absolute rate of growth—​Stationary method of record—​Moving plate method—​Precaution against physical disturbance—​Determination of latent period and time-relations of response—​Advantages of the Crescograph—​Magnetic amplification—​The Demonstration Crescograph151

XI.—EFFECT OF TEMPERATURE ON GROWTH.

Method of discontinuous observation—Method of continuous observation—​Determination of the cardinal points of growth—​The Thermocrescent curve—​Relation between temperature and growth173

XXII.—EFFECT OF CHEMICAL AGENTS ON GROWTH.

Effect of stimulants—Effect of anæsthetics—​Action of different gases—​Action of poisons183

XIII.—EFFECT OF VARIATION OF TURGOR AND OF TENSION ON GROWTH.

Response to positive variation of turgor—​Method of irrigation—​Effect of artificial increase of internal hydrostatic pressure—​Response to negative variation of turgor—Method of plasmolysis—​Effect of alternative variations of turgor on growth—​Response of motile and growing organs to variation of turgor—​Effect of external tension188

XIV.—EFFECT OF ELECTRICAL STIMULUS ON GROWTH.

Effect of intensity—Effect of continuous stimulation—​Continuity between ‘incipient’ and actual contraction—​Immediate effect and after-effect195

XV.—EFFECT OF MECHANICAL STIMULUS ON GROWTH.

Effect of mechanical irritation—Effect of wound200

XVI.—ACTION OF LIGHT ON GROWING ORGANS.

Method of experiment—Normal effect of light—​Determination of the latent period—​Effect of intensity of light—​Effect of continuous light—​Effects of different rays of the spectrum205

XVII.—EFFECT OF INDIRECT STIMULUS ON GROWTH.

Mechanical and electrical response to Indirect Stimulus—​Variation of growth under Indirect Stimulus—​Effects of Direct and Indirect Stimulus213

XVIII.—RESPONSE OF GROWING ORGANS IN STATE OF SUB-TONICITY.

Theory of assimilation and dissimilation—​Unmasking of positive effect—​Modi­fi­ca­tion of response under artificial depression of tonic condition—​Positive response in sub-tonic specimen—​Abnormal ac­cel­er­ation of growth under stimulus—​Continuity between abnormal and normal responses—​Positive response to sub-minimal stimulus219

XIX.—RESUMPTION OF AUTONOMOUS PULSATION AND OF GROWTH UNDER STIMULUS.

Resumption of pulsatory activity of Desmodium leaflet at standstill—​Renewal of growth under stimulus—​General laws of effects of Direct and Indirect Stimulus227

XX.—ACTION OF LIGHT AND WARMTH ON AUTONOMOUS ACTIVITY.

The Oscillating Recorder—Record of pulsation of Desmodium gyrans—​Effect of diffuse light in diminution of amplitude and reduction of diastolic limit of pulsation—Antagonistic action of warmth in reduction of systolic limit233

XXI.—A COMPARISON OF RESPONSES IN GROWING AND NON-GROWING ORGANS.

Contractile response of growing and non-growing organs—Time-relations of mechanical response of pulvinated and growing organs—​Similar modi­fi­ca­tion of response under condition of sub-tonicity—​Opposite effects of Direct and Indirect stimulus—Exhibition of negative electric response under Direct, and positive electric response under Indirect stimulus—​Similar modi­fi­ca­tion of autonomous activity in Desmodium gyrans and in growing organs under parallel conditions—​Similar excitatory effects of various stimuli on pulvinated and growing organs—​Similar discriminative excitatory effects of various rays in excitation of motile and growing organs—​Action of white light—​Action of red and yellow lights—​Action of blue light—​Action of ultra-violet rays—​Action of infra-red rays—​Diverse modes of response to stimulus—​Mechanical response—​Electromotive response—​Response by variation of electric resistance239

ILLUSTRATIONS.