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 tension[188]

XIV.—EFFECT OF ELECTRICAL STIMULUS ON GROWTH.

Effect of intensity—Effect of continuous stimulation—​Continuity between ‘incipient’ and actual contraction—​Immediate effect and after-effect[195]

XV.—EFFECT OF MECHANICAL STIMULUS ON GROWTH.

Effect of mechanical irritation—Effect of wound[200]

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 spectrum[205]

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 Stimulus[213]

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