of the Neodarwinians so far as natural selection goes. By far the most important nexus between Darwin and Weismann, when it comes to the deeper reaches of biological theory, is through Darwin's pangenesis hypothesis and Weismann's germ-plasm-determinant doctrine. This I treat at length elsewhere. It may be left to one side here because of its relative unimportance as touching Darwin's work proper, though of fundamental importance to an exhaustive discussion of the present status of biological philosophy.
Mr. Wallace's ungrudging recognition of Darwin's towering genius as compared with his own is one of the particularly bright and inspiriting examples of what personal relationship between men may be. And to Mr. Wallace is the greater honor because his was the lesser intellectual endowment and achievement.
Turning from Mr. Wallace's beautifully deferential attitude toward his friend, to the facts upon which he based this, what do we find?
We have already seen that Darwin had convinced himself of the truth of descent with modification before he thought of natural selection, and that it was the essay of Malthus on population that gave him the idea of struggle and survival. On December 22, 1857, he said in a letter to Mr. Wallace:
My work at which I have now been at work more or less for twenty years, will not fix or settle anything; but I hope it will aid by giving a large collection of facts, with one definite end.[1] (Italics mine.)
It should be remembered that Malthus's essay was read in 1837.
The circumstances under which Mr. Wallace became the co-propounder of evolution and co-discoverer of natural selection are told by himself. He says:
After writing the preceding paper (On the Law which has Regulated the Introduction of New Species) the question of how changes in species could have been brought about was rarely out of my mind, but no satisfactory conclusion was reached till February, 1858. At that time I was suffering from a rather severe attack of intermittent fever at Ternate in the Moluccas, and one day, while lying on my bed during the cold fit, wrapped in blankets, though the thermometer was 88° Fahrenheit, the problem again presented itself to me, and something led me to think of the "positive checks" described by Malthus in his "Essay on Population," a work I had read several years before, and which had made a deep and permanent impression on my mind. These checks—war, disease, famine and the like—must, it occurred to me, act on animals as well as man. Then I thought of the enormously rapid multiplication of animals, causing these checks to be much more effective in them than in the case of man; and while pondering vaguely upon this fact there suddenly flashed upon me the idea of the survival of the fittest—that the individuals removed by these checks must be on the whole inferior to those that survived. In the two hours that elapsed before my ague fit was over, I had thought out almost the whole of the theory, and the same evening I sketched the draft of my paper, and in the two succeeding evenings wrote it out in full, and sent it by the next post to Mr. Darwin.
- ↑ "Letters," I., p. 467.
