OF PLANTS. 285
may be observed towards summer to shoot forth stems which invariably grow in the direction of the chinks through which the light comes into the cellar, and to continue thus growing until they at last reach the aperture which receives the light directly. In such cases potato-stalks have been known to reach a length of twenty feet; whereas under ordinary circumstances, even such as are most favourable to the growth of the potato, the stalk is seldom longer than from three to four feet. It is interesting to watch closely the course taken by a potato-stalk thus growing in darkness, in its endeavours to reach the light. It tries to do so by the shortest road, but not being firm enough to grow straight across through the air without support, it lets itself drop on to the floor, and thus creeps along the ground till it reaches the nearest wall, up which it then climbs." Even this botanist too is led by his facts to the following assertion (p. 576): "On observing the freedom of movement of oscillatoria and other inferior plants, we may perhaps have no alternative but to attribute a species of will to these beings."
Creepers bear distinct evidence as to manifestation of will in plants; for, when they find no support near enough for their tendrils to cling to, they invariably direct their growth towards the shadiest place, or even towards a piece of dark-coloured paper, wherever it may be placed; whereas they avoid glass, on account of its glitter. In the Philosophical Transactions of 1812, Thomas Andrew Knight relates some very pleasing experiments on this subject (especially with ampelopsis quinquefolia,) 1 although he strives hard to explain the matter mechanically, and will not admit that it is a manifestation of will. I appeal to his experiments, not to the conclusions he draws from them. A good test might be, to plant several free creepers in a
1 These have been translated for the Bibliothèque Britannique, Section des Sciences et Arts, vol. 52
286
