8 



THE EVOLUTION OF BIEDS. 



Its sim- 

 plicity the 

 great charm 

 of Darwin's 

 theory. 



Fortuitous 

 variations 

 its weak 

 point. 



Simul- 

 taneous ap- 

 pearance of 

 a variation. 



Douhted by 

 Romanes. 



Admitted by 

 Wallace. 



Cannot be 

 accidental. 



suppose a special creation of every species was bad enough and looked weak, as if the 

 clock always wanted mending or altering to make it go right. But to suppose, not precisely 

 a special creation, but a special interference, in a given direction with the law of li&e 

 producing like, at every generation, was a thousand times worse ; and, consequently, of two 

 evils scientific men chose the least, and the theory of Evolution was laid on the shelf until 

 Charles Darwin and Wallace took it down again. The fact of the survival of the fittest in 

 the struggle for existence is such a simple theory that a child can understand it ; and not 

 only the scientific world, but almost every educated man, accepted the new theory of 

 Evolution as soon as they saw, or thought they saw, the simplicity of the machinery by 

 which it is produced. 



That like produces like is an axiom which, taken broadly, is proved not by thousands, 

 but by millions of facts. That nevertheless children always vary slightly from their parents 

 is equally self-evident. That these variations are accidental is a conclusion easily arrived 

 at by an unscientific mind, and even men of science, one might say even the greatest men 

 of science, have been content to call variations produced by undiscoverable or undiscovered 

 causes, fortuitous variations. That individuals possessing a useful variation should live long 

 and leave many descendants, whilst those possessing a harmful variation should die early 

 and leave few descendants, seems to be a truism. That variations are hereditary is a fact, 

 which, if not of universal application, is almost so ; and the preservation and gradual 

 extension of useful variations in the course of millions of generations is a corollary which 

 most scientific minds have easily accepted. The whole argument is perfectly fascinating in 

 its simplicity, and having been accepted so universally, it is difiicult to imagine that there 

 can be a hitch in it. 



That there is a hitch in it can scarcely be doubted by any unbiassed mind who reads 

 the literature relating to the " swamping eff'ects," as Romanes calls it, of interbreeding. 

 To remove the hitch it is necessary to assume that the same beneficial variation should arise 

 simultaneously in a sufficient number of individuals to prevent its being swamped by the 

 interbreeding of the individuals who possess it with those that do not. This Romanes calls 

 " a very large assumption " (Journ. Linn. Soc, Zoology, xix. p. 343) ; but Wallace replies 

 (Fortnightly Review, 1886, Sept., p. 307) "that which Mr. Romanes regards as a very 

 large assumption is, I maintain, a very general fact, and, at the present time, one of the best 

 established facts in natural history." 



If it be so, and I see no reason to doubt the statement, it seems to me that the 

 following corollaries are inevitable. 



The simultaneous appearance, and its repetition in successive generations, of a beneficial 

 variation in a large number of individuals, in the same locality, cannot possibly be ascribed 

 to chance. 



The admission that such coincidences might occur once in a thousand years is perhaps 

 not a very large assumption, but the suggestion that rare accidents of this kind are an 

 important part of the machinery of Evolution is simply puerile— so much so, in fact, that 

 writer has ever hinted at the possibihty of its truth. 



no 



