Page:Popular Science Monthly Volume 9.djvu/708

680 to his purposes has become what it is in obedience to an inherent tendency to exchange its original condition for a better one. And it is by taking advantage of this tendency and creating such better conditions that man has drawn it into his service.

This willingness and often eagerness in plants to change their habitat, sometimes without the least acclimation, enlarges, therefore, from the mere lusus naturæ which it at first appeared to be, into a law which is coextensive with plant-life. In view of the facts adduced, and others which will occur to the reader, we may conclude that the law of adaptation as popularly held requires extensive qualification if allowed to stand at all; that it is rather apparent than real; that large classes of facts are marshaled against it, and that some wider law is perpetually overruling it. The adaptations of Nature of which we hear so much are not perfect. Nature does not provide each species with a habitat best suited to its fullest development. But every plant is at all times ready to change its habitat for a better one, and this is actually going on whenever occasion permits.

Let us now inquire whether the facts enumerated admit of any general explanation. Mr. Meehan proposes to account for the better growth of swamp-trees in drier soil by maintaining that their seeds cannot germinate in dry ground. If this be true, it is a worse commentary on the theory of adaptation than I am willing myself to make without further proof. Certainly no intelligent adapting power could originate so gross and apparently gratuitous an inadaptation as an organism doomed to live out its existence under conditions unfavorable to its healthy development, because, forsooth, it could begin its career only under such conditions! But, as both the theory and the commentary rest on a teleological basis, they are both worthless from a scientific point of view.

But, however this may apply to the trees enumerated by him, it certainly does not apply to many plants of the same class which I have named, for florists propagate them from the seed when they choose. Still less can this explanation be admitted to account for any of the other classes from which illustrations have been drawn. And, indeed, I am not aware that any attempt has ever been made to bring forward a rational explanation of a general character for the facts under consideration. Botanists, generally, seem to have been either too much dazed by the light of those more universal and striking features to which attention was called at the outset, or too intent on the special study of the facts themselves, independent of the lessons they inculcate, to have worked out a solution for the problem I have been seeking to present. But the chief obstacle, after all, to such a solution, is to be found in the satisfaction which every one seems to feel with the old explanation, viz., that plants grow in particular places because they are adapted to them and to no other, which, as we have seen, is opposed by a strong array of facts.