When the first edition of the “Origin of Species” was published in 1859, Darwin wrote that he by no means expected to convince experienced naturalists whose minds were stocked with a multitude of facts, all regarded during a long course of years from a point of view directly opposite to his.  He looked forward with confidence, however, to the future, to young and rising naturalists, who would be able to view both sides of the question with impartiality.  He predicted that, when the conclusions reached by him and by Mr. Wallace concerning the origin of species should be generally accepted, there would be a considerable revolution in natural history.  Naturalists, for instance, would be forced to acknowledge that the only distinction between species and well-marked varieties is that the latter are known or believed to be connected at the present day by intermediate gradations, whereas species were formerly, though they are not now, thus connected.  It might thus come to pass that forms generally acknowledged in 1859 to be merely varieties, would thereafter be thought worthy of specific names; in which case scientific and common language would come into accordance.  In short, Darwin looked forward to the time when species would have to be treated in the same manner as genera are treated by those naturalists who admit that genera are merely artificial combinations made for convenience.

Darwin also foresaw that when his theory of the origin of species should be adopted, other and more general departments of natural history would rise greatly in interest.  The terms used by naturalists—­such terms as affinity, relationship, community of type, paternity, morphology, adaptive characters, rudimentary and abortive organs, etc.—­would cease to be metaphorical, and would have a plain signification.  “When,” he wrote, “we no longer look at an organic being as a savage looks at a ship, as something wholly beyond his comprehension; when we regard every production of nature as one which has had a long history; when we contemplate every complex structure and instinct as the summing up of many contrivances, each useful to the possessor, in the same way as any great mechanical invention is the summing up of the labor, the experience, the reason, and even the blunders of numerous workmen; when we thus view each organic being, how far more interesting—­I speak from experience—­does the study of natural history become.”  Once more:  “When we can feel assured that all the individuals of the same species, and all the closely allied species of most genera, have within a not very remote period descended from one parent, and have migrated from some one birthplace; and when we better know the many means of migration, then, by the light which geology now throws, and will continue to throw, on former changes of climate and of the level of the land, we shall surely be enabled to trace in an admirable manner the former migrations of the inhabitants of the whole world.”