It is well known that after the discovery of almost every great truth a sort of feeling or instinct of it can be traced back in obscure hints, in chance expressions, in vague guesses, in flights of imagination, so that people very soon begin to fancy that they have all along understood and maintained the very theory, which, on its first appearance, they violently rejected as something false and even vicious. Darwinism has this characteristic of truth, that it has often been obscurely anticipated. It has this other characteristic, that its fiercest opponents have already begun insensibly to adopt its conclusions, and to speak its language, to opine, even, that the credit of its promulgation belongs to themselves. In Mr. Darwin’s own historical sketch of the rise and progress of his doctrine, he does full justice to those who have preceded and who have worked with him in bringing it to light and in establishing its foundations. The opinion that species originate, not by successive miraculous interpositions or acts of creation, but by birth, was held as far back as 1794-5, by four men of distinguished genius, by Lamarck, by Mr. Darwin’s own grandfather, Dr. Erasmus Darwin, by Geoffroy Saint Hilaire, and by the poet Goethe. In the present day, Mr. Wallace, Mr. Herbert Spencer, the great zoologist Van Baer, and others, independently of Mr. Darwin, seem to have come more or less to the same conclusions, which have been warmly espoused and powerfully vindicated by Dr. Hooker, Professor Huxley, and Sir Charles Lyell. I mention these names because it seems to be their due, and not for the sake of giving weight to any argument because of the scientific renown of its advocates; there are names, it may be, equally distinguished on the opposite side. But one thing ought to be observed, that the progress of scientific enquiry has achieved so much during the last hundred years that the opinions of the older Naturalists have an importance when they agree with modern conclusions, which they cannot have when they differ from them, unless it can be shown that the observations, the experiments, the discoveries of late years had all been made by, or were known to, the earlier enquirers. For those, however, who think the opinions of a past generation of necessity more trustworthy than those of the present, Sir Charles Lyell has done well to point out that Linnæus himself looked forward to a time when it should be proved that in botany, at least, all species of a genus had descended from the same mother[4].