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Show 190 DARWINIAN A. established it follows almost of course that the very nearly-rela:ed species in Central Asia~ in. Japan? in California, and even our own live-oak with Its Mexwan relatives, may probably enough .be regarded as early offshoots from the same stock with Q. Ilex. In brief-not to continue these abstracts and remarks, and without reference to Darwin's p~rticular theory (which De Oandolle at the close very fairly considers)- if existing species, or many .of them, are as ancient as they are now generally though~ to be, and were ·subject to the physical and geo?raph~cal cban~es (among them the coming and t~e g?mg ?f ~be glamal epoch) which this antiquity Imphes; If In former times they were as liable to varjation a~ they now ~re ; and i£ the individuals of the same species may cla1m a common local origin, then we cannot wonder that " the theory of a succession of forms by deviations of anterior forms " should be regarded as "the most natural hypothesis," nor at the general advance made toward its acceptance. . The question being, not, how plants and ammals originated, but, how came the existing animals and plants to be just where they are and what ~bey_a~·e, it is plajn that naturalists interested _in such I~qm~·1es are mostly looking for the answer In one duect:on. The general drift of opinion, or at least of expectatiOn, is exemplified by this essay of De Candolle ; and the set and force of the current are seen by noticing how it carries along naturalists of widely different views and prepossessions-some faster and fa:·ther than others- but all in one way. The tendency Is, we may say, to extend the law of continuity, or something analo- SPECIES AS TO VARIATION, E!O. 191 gous to it, from inorganic to organic Nature, and in the latter to connect the present with the past in some sort of material connection. The generalization may indeed be expressed so as not to assert that the connection is genetic, as in Mr. Wallace's formula: "Every species has come into existence coincident both in time and space with preexisting closely-allied species." Edward Forbes, who may be called the originator of this whole line of inquiry, long ago expressed a similar view. But the only material sequence we know, or can clearly conceive, in plants and animals, is that from parent to progeny; and, as De Candolle implies, the origin of species and that of races can hardly be much unlike,· nor governed by other than the same laws, whatever these may be. The progress of opinion upon this subject in one generation is not badly represented by that of De Candolle himself, who is by no means prone to adopt new views without much consideration. In an elementary treatise published in the year 1835, he adopted and, if ;'e rightly remember, vigorously maintained, Schou w's Idea of the double or multiple origin of species, at least of some species-a view which has been carried out to its ultimate development on1y perhaps by Agassiz, in the denial of any necessary genetic connection among· the individuals of the same species, or of any original localization more restricted than the area now occupied by the species. But in 1855, in his "Geograp~ ie ~otanique," the multiple hypothesis, although in prmmple not abandoned, loses its point, in view of the probable high antiquity of exis~ing species. The actual vegetation of the world being now regarded as a |