The second complaint against me is to the effect that I have made no original experiments, but have taken all my facts at second hand. This is true, but I do not see what it has to do with the question. If the facts are sound, how can it matter whether A or B collected them? If Professor Huxley, for example, has made a series of valuable original observations (not that I know of his having done so), why am I to make them over again? What are fact-collectors worth if the fact co-ordinators may not rely upon them? It seems to me that no one need do more than go to the best sources for his facts, and tell his readers where he got them. If I had had occasion for more facts I daresay I should have taken the necessary steps to get hold of them, but there was no difficulty on this score; every text-book supplied me with all, and more than all, I wanted; my complaint was that the facts which Mr. Darwin supplied would not bear the construction he tried to put upon them; I tried, therefore, to make them bear another which seemed at once more sound and more commodious; rightly or wrongly I set up as a builder, not as a burner of bricks, and the complaint so often brought against me of not having made experiments is about as reasonable as complaint against an architect on the score of his not having quarried with his own hands a single one of the stones which he has used in building. Let my opponents show that the facts which they and I use in common are unsound, or that I have misapplied them, and I will gladly learn my mistake, but this has hardly, to my knowledge, been attempted. To me it seems that the chief difference between myself and some of my opponents lies in this, that I take my facts from them with acknowledgment, and they take their theories from me—without. One word more and I have done. I should like to say that I do not return to the connection between memory and heredity under the impression that I shall do myself much good by doing so. My own share in the matter was very small. The theory that heredity is only a mode of memory is not mine, but Professor Hering’s. He wrote in 1870, and I not till 1877. I should be only too glad if he would take his theory and follow it up himself; assuredly he could do so much better than I can; but with the exception of his one not lengthy address published some fifteen or sixteen years ago he has said nothing upon the subject, so far at least as I have been able to ascertain; I tried hard to draw him in 1880, but could get nothing out of him. If, again, any of our more influential writers, not a few of whom evidently think on this matter much as I do, would eschew ambiguities and tell us what they mean in plain language, I would let the matter rest in their abler hands, but of this there does not seem much chance at present.