horses and cattle.  In all candor we must at least concede that such considerations suggest a genetic descent from the drift period down to the present, and allow time enough—­if time is of any account—­for variation and natural selection to work out some appreciable results in the way of divergence into races or even into so-called species.  Whatever might have been thought, when geological time was supposed to be separated from the present era by a clear line, it is certain that a gradual replacement of old forms by new ones is strongly suggestive of some mode of origination which may still be operative.  When species, like individuals, were found to die out one by one, and apparently to come in one by one, a theory for what Owen sonorously calls “the continuous operation of the ordained becoming of living things” could not be far off.

That all such theories should take the form of a derivation of the new from the old seems to be inevitable, perhaps from our inability to conceive of any other line of secondary causes, in this connection.  Owen himself is apparently in travail with some transmutation theory of his own conceiving, which may yet see the light, although Darwin’s came first to the birth.  Different as the two theories will probably be in particulars, they cannot fail to exhibit that fundamental resemblance in this respect which betokens a community of origin, a common foundation on the general facts and the obvious suggestions of modern science.  Indeed,—­to turn the point of a taking simile directed against Darwin,—­the difference between the Darwinian and the Owenian hypotheses may, after all, be only that between homoeopathic and heroic doses of the same drug.

If theories of derivation could only stop here, content with explaining the diversification and succession of species between the tertiary period and the present time, through natural agencies or secondary causes still in operation, we fancy they would not be generally or violently objected to by the savans of the present day.  But it is hard, if not impossible, to find a stopping-place.  Some of the facts or accepted conclusions already referred to, and several others, of a more general character, which must be taken into the account, impel the theory onward with accumulated force. Vires (not to say virus) acquirit eundo.  The theory hitches on wonderfully well to Lyell’s uniformitarian theory in geology,—­that the thing that has been is the thing that is and shall be,—­that the natural operations now going on will account for all geological changes in a quiet and easy way, only give them time enough, so connecting the present and the proximate with the farthest past by almost imperceptible gradations,—­a view which finds large and increasing, if not general, acceptance in physical geology, and of which Darwin’s theory is the natural complement.

So the Darwinian theory, once getting a foothold, marches boldly on, follows the supposed near ancestors of our present species farther and yet farther back into the dim past, and ends with an analogical inference which “makes the whole world kin.”  As we said at the beginning, this upshot discomposes us.  Several features of the theory have an uncanny look.  They may prove to be innocent:  but their first aspect is suspicious, and high authorities pronounce the whole thing to be positively mischievous.