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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1920 Excerpt: ...rain on to the leaf. In the Indian plant already referred to, most remarkable movements immediately follow a shower of rain. The leaves which first come in contact with the drops fold together downwards, but not only do these leaves do so, but actually, also, those in closest proximity to them, even though no actual drops fall thereon. Well might such a plant be termed "sensitive." Even the leaf-stalk, which bears the mass of leaves, bends in the direction of the earth; and the practical consequence of these movements is that the drops of rainwater flow over the bent stalk, and over the hanging leaves, so that all the moisture is immediately drained off, and none remains upon the surface. No better example can be imagined illustrative of plant intelligence, or movements directed by some principle towards the attainment of a definite purpose. Why The Leaves Fold Up Very similar processes are seen in the leaves of the sundew, and in those of Venus's fly-trap, as well as in some of the mimosas. The actual movements are not identical in all these cases, but they are produced by the same sort of influences, and for precisely analogous purposes. The freeing of the plant from raindrops, however, though obviously one of the objects in these movements, is not the only one. This may be concluded from the fact that quite other conditions than rain produce the same movements, particularly such factors as hot, dry winds, impregnated with particles of dust or sand. Here it is obviously to prevent excessive transpiration that the leaves fold together. So we may safely conclude that several different advantages accrue to the plant in virtue of the powers of movement we have been describing. At night the loss of heat by radiation is minimized. In the heat of the d...