“Thus from the earliest times it has been man’s study to select from the countless forms of vegetation at his disposal those that best lend themselves to improvement. The greater number of species have remained useless to us, but others, predestined no doubt, and created especially with a view to man’s needs, have responded to our efforts and acquired through cultivation qualities of prime importance, since our sustenance depends on them. Nevertheless the improvement attained is not so radical that we can count on its permanence if our vigilance relaxes. The plant always tends to revert to its primitive state. For example, let the gardener leave the headed cabbage to itself without fertilizing, watering, or cultivating it; let him leave the seeds to germinate by chance wherever the wind blows them, and the cabbage will quickly part with its compact head of white leaves and resume the loose green leaves of its wild ancestors. In like manner the vine, set free from man’s constant attention, will degenerate into the little-esteemed wild species that haunts our hedge-rows and yields a scant harvest that will not, all together, be worth a single bunch of cultivated grapes. The pear-tree, if neglected, will again be found on the outskirts of our woods, once more bristling with long sharp thorns and bearing under-sized and extremely unpalatable fruit. Under like conditions the plum-tree and the cherry-tree will bear nothing but stones covered with a sour skin. In short, all the riches of our orchards will in similar circumstances undergo such deterioration as to be worthless to us. “This reversion to the wild state occurs even under cultivation and in spite of efforts to prevent it when seed is used for propagating the plant. Suppose the seeds from an excellent pear are put into the ground. Well, the trees that spring from those seeds will bear for the most part only mediocre or poor, even very poor, pears. Another planting is made with the pits of the second generation, and the result shows still further decline. Thus if the experiment is continued with seeds taken each time from the immediately preceding generation, the fruit, becoming smaller and smaller, bitterer and harder, will at last return to the sorry wild pear of the thicket. “One more example. What flower equals the rose in nobleness of carriage, in perfume and brilliant coloring? Suppose we plant the seeds of this superb flower; its descendants will turn out to be miserable bushes, nothing but wild roses like those of our hedges. But we need not be surprised at this. The noble plant had the wild rose for ancestor, and in trying to propagate it by its seed we have simply caused it to resume its native characteristics.