Again, in the case of some weeping trees, whose boughs spring up into fresh trees when they have reached the ground, who shall say at what time they cease to be members of the parent tree? In the case of cuttings from plants it is easy to elude the difficulty by making a parade of the sharp and sudden act of separation from the parent stock, but this is only a piece of mental sleight of hand; the cutting remains as much part of its parent plant as though it had never been severed from it; it goes on profiting by the experience which it had before it was cut off, as much as though it had never been cut off at all. This will be more readily seen in the case of worms which have been cut in half. Let a worm be cut in half, and the two halves will become fresh worms; which of them is the original worm? Surely both. Perhaps no simpler case than this could readily be found of the manner in which personality eludes us, the moment we try to investigate its real nature. There are few ideas which on first consideration appear so simple, and none which becomes more utterly incapable of limitation or definition as soon as it is examined closely. Finally, Mr. Darwin (“Plants and Animals under Domestication,” vol. ii. p. 38, ed. 1875), writes— “Even with plants multiplied by bulbs, layers, &c., which may _in one sense_ be said to form part of the same individual,” &c., &c.; and again, p. 58, “The same rule holds good with plants when propagated by bulbs, offsets, &c., which _in one sense_ still form parts of the same individual,” &c. In each of these passages it is plain that the difficulty of separating the personality of the offspring from that of the parent plant is present to his mind. Yet, p. 351 of the same volume as above, he tells us that asexual generation “is effected in many ways—by the formation of buds of various kinds, and by fissiparous generation, that is, by spontaneous or artificial division.” The multiplication of plants by bulbs and layers clearly comes under this head, nor will any essential difference be felt between one kind of asexual generation and another; if, then, the offspring formed by bulbs and layers is in one sense part of the original plant, so also, it would appear, is all offspring developed by asexual generation in its manifold phrases.