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the facts, which involve, as Sir Joseph Hooker remarks, "a continuous current of vegetation from north to south,” going much further back than the glacial period, because it has led to the transmission not of existing species only, but of distinct representative species, and even distinct genera, showing that the process must have been going on long before the cold period. The reason why Darwin was unaffected by these various difficulties may perhaps be found in the circumstance that he had held his views for so many years almost un challenged. In a letter to Sir Charles Lyell, in 1866, he says, “I feel a strong conviction that soon every one will believe that the whole world was cooler during the glacial period. Remember Hooker's wonderful case recently discovered of the identity of so many temperate plants on the summit of Fernando Po, and on the mountains of Abyssinia. I look at it as certain that these plants crossed the whole of Africa, from east to west, during the same period. I wish I had published a long chapter, written in full, and almost ready for the press, on this subject which I wrote ten years ago. It was impossible in the Origin' to give a fair abstract” (“More Letters,” vol. i. p. 476). Having thus held his views for twenty-five years, they had become so firmly impressed upon his mind that he was unable at once to give them up, however strong might be the arguments against them. This particular difference, however, is not one which in any way affects the theory of natural selection.

4. Pangenesis, and the Heredity of Acquired Characters. -Darwin always believed in the inheritance of acquired characters, such as the effects of use and disuse of organs and of climate, food, etc., on the individual, as did almost every naturalist, and his theory of pangenesis was invented to explain this among other affects of heredity. I therefore accepted pangenesis at first, because I have always felt it a relief (as did Darwin) to have some hypothesis, however provisional and improbable, that would serve to explain the facts; and I told him that “I shall never be able to give it up till a better one supplies its place." I never imagined

that it could be directly disproved, but Mr. F. Galton's experiments of transfusing a large quantity of the blood of rabbits into other individuals of quite different breeds, and afterwards finding that the progeny was not in the slightest degree altered, did seem to me to be very nearly a disproof, although Darwin did not accept it as such. But when, at a much later period, Dr. Weismann showed that there is actually no valid evidence for the transmission of such characters, and when he further set forth a mass of evidence in support of his theory of the continuity of the germ-plasm, the “better theory” was found, and I finally gave up pangenesis as untenable. But this new theory really simplifies and strengthens the fundamental doctrine of natural selection.

It will thus appear that none of my differences of opinion from Darwin imply any real divergence as to the overwhelming importance of the great principle of natural selection, while in several directions I believe that I have extended and strengthened it. The principle of "utility,” which is one of its chief foundation-stones, I have always advocated unreservedly; while in extending this principle to almost every kind and degree of coloration, and in maintaining the power of natural selection to increase the infertility of hybrid unions, I have considerably extended its range. Hence it is that some of my critics declare that I am more Darwinian than Darwin himself, and in this, I admit, they are not far wrong.

CHAPTER XXVI

MY FRIENDS AND ACQUAINTANCES-SPENCER, HUXLEY,

MIVART, ETC.

Soon after my return home, in 1862 or 1863, Bates and I, having both read “First Principles ” and been immensely impressed by it, went together to call on Herbert Spencer, I think by appointment. Our thoughts were full of the great unsolved problem of the origin of life—a problem which Darwin's "Origin of Species " left in as much obscurity as ever--and we looked to Spencer as the one man living who could give us some clue to it. His wonderful exposition of the fundamental laws and conditions, actions and interactions of the material universe seemed to penetrate so deeply into that “nature of things” after which the early philosophers searched in vain and whose blind gropings are so finely expressed in the grand poem of Lucretius, that we both hoped he could throw some light on that great problem of problems. I forget the details of the interview, but I think Bates was chief spokesman, and expressed our immense admiration of his work, and that as young students of nature we wished to have the honour of his acquaintance. He was very pleasant, spoke appreciatively of what we had both done for the practical exposition of evolution, and hoped we would continue to work at the subject. But when we ventured to touch upon the great problem, and whether he had arrived at even one of the first steps towards its solution, our hopes were dashed at once. That, he said, was too fundamental a problem to even think of solving at present. We did not yet know enough of matter in its essential constitution nor of the various forces of nature ; and all he could say was

that everything pointed to its having been a development out of matter—a phase of that continuous process of evolution by which the whole universe had been brought to its present condition. So we had to wait and work contentedly at minor problems. And now, after forty years, though Spencer and Darwin and Weismann have thrown floods of light on the phenomena of life, its essential nature and its origin remain as great a mystery as ever. Whatever light we do possess is from a source which Spencer and Darwin neglected or ignored.

In 1865, when Spencer was, I believe, one of the editors of The Reader, he asked me to write an article on the treatment of savage races, with special reference to some cases of the barbarity of settlers in Australia that had recently been published. This I did, and the article appeared in the issue of June 17. Ten years later, on November 13, 1875, he wrote to ask me where and when this article had appeared, adding, "I ask the question because I contemplate giving Dr. Bridges a castigation for the unwarranted sneer at the close of his article in the Fortnightly." I may add that I have reprinted my article (with some additions referring to recent facts) in my “Studies Scientific and Social,” vol. ii. p. 107.

The first letter I received from Spencer was when I sent him my paper on "The Origin of Human Races under the Law of Natural Selection." He said that he had read it with great interest, and added, "Its leading idea is, I think, undoubtedly true,” concluding with a hope that I would pursue the inquiry.

Soon afterwards he invited me to dine with him in Bayswater, where he lived for many years in a boarding-house with rather a commonplace set of people—retired Indian officers and others; and I afterwards visited him there several times. I was amused when some popular error was solemnly put forth at dinner as the explanation of some phenomenon; Spencer would coolly tell them that it was quite incorrect, and then proceed to explain why it was so, and on principles of evolution could not be otherwise. In the evening, after we

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had had a little private conversation, we would go into the drawing-room where there was music, and Spencer would sometimes play on his flute. On remarking to him one day that I wondered he could live among such unintellectual people, he said that he had purposely chosen such a home in order to avoid the mental excitement of too much interesting conversation; that he suffered greatly from insomnia, and that he found that when his evenings were spent in commonplace conversation, hearing the news of the day or taking part in a little music, he had a better chance of sleeping.

In the autumn of 1867 I read the Duke of Argyll's “Reign of Law," and though I found much that was erroneous and weak in argument, I thought his discussion of the mode of flight in birds, founded largely on personal observation, was very good ; in fact, the best I had seen. Spencer had also read this, and differed from me, thinking that important parts of the duke's theory of flight was not true, because they would not apply equally to bats; and we had quite a discussion on the subject. The next day, after thinking the matter over, I wrote him a long letter of eight pages, trying to show that the general principles of flight in birds, bats, and insects were the same; but that in birds there were additional special adaptations that render their flight more perfect, and their power of motion through the air, under adverse conditions, more varied and more complete. The duke, dealing with birds only, had dwelt most on these special adaptations (chiefly, if I remember, the beautiful overlapping and movements of the separate feathers increasing resistance during the downward, and decreasing it during the upward stroke) which did not exist in bats or in insects. I also showed that although this adaptation was absent in the wings of insects, the general form and movements of the wings were similar and produced similar, but not identical results. In his reply he admitted the accuracy of my description of the flight of insects, but made the following remark in furtherance of his former objection as regards the duke's account of the flight of birds : “If you will move an outstretched wing backwards and forwards with equal

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