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And it a truly interesting book, Mr. Darwin says that, "Light seems to act on the tissues of plants, almost in the same manner as it does on the nervous system of animals." [Movement in plants, p. 566.] It is another remarkable circumstance that this sensitiveness to light seems to be localised in the tips of the cotyledons; just as the sensitiveness to light is localised in the eyes of animals. The same eminent person just mentioned compares the tip of the radicle of a plant to the brain; in that it is able to distinguish between rough and smooth substances, avoiding one and turning towards the other; this faculty being confined to a very small area. Experiments on the influence of the electric light upon plants have led to the conclusion that it is efficacious in promoting growth; that plants do not require a period of rest during the 24 hours of the day, but make increased and vigorous progress if subjected during daytime to sunlight and during night to electric light; and that, while under the influence of electric light, plants can sustain increased stove-heat without collapsing, a circumstance favourable to forcing by electric light.