I have long felt that evolution must stand or fall according as it is made to rest or not on principles which shall give a definite purpose and direction to the variations whose accumulation results in specific, and ultimately in generic differences. In other words, according as it is made to stand upon the ground first clearly marked out for it by Dr. Erasmus Darwin and afterwards adopted by Lamarck, or on that taken by Mr. Charles Darwin. There is some reason to fear that in consequence of the disfavour into which modern Darwinism is seen to be falling by those who are more closely watching the course of opinion upon this subject, evolution itself may be for a time discredited as something inseparable from the theory that it has come about mainly through "the means" of natural selection. If people are shown that the arguments by which a somewhat startling conclusion has been reached will not legitimately lead to that conclusion, they are very ready to assume that the conclusion must be altogether unfounded, especially when, as in the present case, there is a vast mass of vested interests opposed to the conclusion. Few know that there are other great works upon descent with modification besides Mr. Darwin's. Not one person in ten thousand has any distinct idea of what Buffon, Dr. Darwin, and Lamarck propounded. Their names have been discredited by the very authors who have been most indebted to them; there is hardly a writer on evolution who does not think it incumbent upon him to warn Lamarck off the ground which he at any rate made his own, and to cast a stone at what he will call the "shallow speculations" or "crude theories" or the "well-known doctrine" of the foremost exponent of Buffon and Dr. Darwin. Buffon is a great name, Dr. Darwin is no longer even this, and Lamarck has been so systematically laughed at that it amounts to little less than philosophical suicide for anyone to stand up in his behalf. Not one of our scientific elders or chief priests but would caution a student rather to avoid the three great men whom I have named than to consult them. It is a perilous task therefore to try and take evolution from the pedestal on which it now appears to stand so securely, and to put it back upon the one raised for it by its propounders; yet this is what I believe will have to be done sooner or later unless the now general acceptance of evolution is to be shaken more rudely than some of its upholders may anticipate. I propose therefore to give a short biographical sketch of the three writers whose works form new departures in the history of evolution, with a somewhat full _resume_ of the positions they took in regard to it. I will also touch briefly upon some other writers who have handled the same subject. The reader will thus be enabled to follow the development of a great conception as it has grown up in the minds of successive men of genius, and by thus growing with it, as it were, through its embryonic stages,