Of {274}course it is only an inexperienced biologist who could long be puzzled by this apparent paradox. He must soon see the true solution of the riddle, if he has read and digested the teachings of Darwin. For the real fact is, in a garden or out of it, most of these plants could get on very well in a great variety of climates or situations--if only they were protected against outside competition. There we have the actual crux of the problem. It is not that the moisture-loving plants cannot live in dry situations, but that the dry-loving plants, specialised and adapted for the post, can compete with them there at an immense advantage, and so, in a very short time, live them down altogether. Every species in a state of nature is continually exposed to the ceaseless competition of every other; and each on its own ground can beat its competitors. But in a garden, the very thing we aim at is just to restrict and prevent competition; to give each species a fair chance for life, even in conditions where other and better-adapted species can usually outlive it. This, in fact, is really at bottom all that we ever mean by a garden--a space of ground cleared, and kept clear, of its natural vegetation (commonly called in this connexion weeds), and deliberately stocked with other plants, most or all of which the weeds would live down if not artificially prevented. We see the truth of this point of view the moment the garden is, as we say, abandoned--that is to say, left once more to the operation of unaided nature. The plants with which we have stocked it loiter on for a while in a feeble and uncertain fashion, but are ultimately choked out by the stronger and better-adapted weeds which compose the natural vegetation of the locality. The dock and nettle live down in time the larkspur and the peony. The essential thing in the garden is, in short, the clearing of the ground from the weeds--that is, in other words, from the native vegetation. A few minor things may or may not be added, such as manuring, turning the soil, protecting with {275}shelter, and so forth; but the clearing is itself the one thing needful. Slight as this point seems at first sight, I believe it includes the whole secret of the origin of tillage, and therefore, by implication, of the gods of agriculture. For, looked at in essence, cultivation is weeding, and weeding is cultivation. When we say that a certain race cultivates a certain plant-staple, we mean no more in the last resort than that it sows or sets it in soil artificially cleared of competing species. Sowing without clearing is absolutely useless. So the question of the origin of cultivation resolves itself at last simply into this--how did certain men come first to know that by clearing ground of weeds and keeping it clear of them they could promote the growth of certain desirable human foodstuffs?