November i, 1894] 



NA TURE 



\ "Recent investigations have utterly shattered the 



ilbelief in cataclysms. The conviction has arisen that the 



I process of the development and metamorphosis of 



[organic beings was gradual and uninterrupted, and that 



sharp lines of demarcation are to be found only where 



considerable changes in the conditions of existence, and 



especially in the distribution of land and water, have 



brought about great modifications in the world of life or 



interruptions in the formation of sediment." (Zittel : 



" Handbuch der Pateontologie." Bd. I. p. 23.) 



And, again, in the recently completed final volume 

 •of this standard work we read : 



"The whole history of the evolution of the mammalia 

 from the Trias to the present day, in spite of all de- 

 ficiencies in the record, plainly shows that the genetic 

 ] -connection of the several Faunas, whatever geological dis- 

 turbances may have taken place, was never completely 

 interrupted ; and that each of these associations of 

 animals has arisen by gradual transformation of the 

 constituents of its predecessor, and has furnished the 

 stock of its successor." (Bd. IV^ p. 764.) 



However often, therefore, thoughtlessness, or 

 polemical dexterity, may confuse issues which are 

 totally distinct, biological evolution rests, in per- 

 fect security, on the firm foundation afforded by the 

 •study of the remains of the animals and plants, which 

 have successively peopled the world during the 

 untold ages of its past history. The coming into 

 being of the present forms of life has happened so, 

 and in no other way. 



And, as I pointed out, si.\teen years ago, 



" It is only the nature of the physiological factors to 

 which that evolution is due which is still open to 

 ■discussion.'' ' 



For me, the claim of the doctrine of evolution 

 i.0 be taken into account in all philosophical and 

 other views of the nature of things turns upon whether 

 it possesses a solid foundation in fact or is a 

 mere speculation. No doubt, whenever astronomers 

 universally accept what is called the Kant-Laplace 

 theory of the heavens, a notable addition will be 

 made to this indispensable objective foundation of 

 the doctrine. Whenever chemists accept the evolu- 

 tion of the so-called elements from a materia prima, 

 there will be a further grand addition. But, for the 

 present, I venture to suppose that the palaiontological 

 base is surest. And, at any rate, so far as the claims 

 ■of science to be heard in regard to the problems of 

 human life are concerned, it is, far and away, the 

 most important. If man has come into existence by 

 the same process of evolution as other animals ; if 

 his history, hitherto, is that of a gradual progress to 

 a higher thought and a larger power over things ; if 

 that history is essentially natural ; the frontiers 

 of the new world, within which scientific method is 

 supreme, will receive such a remarkable extension as 

 to leave little but cloudland for its rival. 



1 " Collected Essays," vol. ii. p. aa6. 

 NO. 1293, VOL. 51] 



Experience teaches me it is by no means im- 

 possible that if I were to stop here, what I have said 

 would be rejjresented, and even believed, to be a 

 repudiation of " Darwinism." Yet no conclusion 

 could be more utterly devoid of foundation. 



" The combined investigations of another twenty years 

 may, perhaps, enable naturalists to say whether the 

 modifying causes and the selective power, which Mr. 

 Darwin has satisfactorily shown to exist in nature, are 

 competent to produce all the effects he ascribed to them ; 

 or whether, on the other hand, he has been led to over- 

 estimate the value of the principle of natural selection, as 

 greatly as Lamarck over-estimated his ''era causa of 

 modification by exercise." 



...."' My sons dig in the vineyard,' were the last 

 words of the old man in the fable ; and though the sons 

 found no treasure they made their fortune by the grapes."' 



These two paragraphs occur at the end of the 

 critical notice of the " Origin of Species," which I 

 wrote in 1859. The citations I have already given 

 from Zittel sufficiently show what has come of 

 "digging in the vineyard"; there is another (Bd. I. 

 p. 42) much to the present purpose. 



" For the naturalist, evolution (</;> Descendeiiz theorie) 

 offers the only natural solution of the problem of the 

 development and succession of organic beings. But as 

 to the causes which bring about the modification of 

 species, and especially the change in a given direction, 

 opinions are yet greatly divided. That the principle of 

 natural selection, discovered by Darwin, leaves many 

 phenomena unexplained is no longer denied by even the 

 warmest followers of Darwin." 



It will be observed that at any rate one of these 

 "warmest followers" has never thought of denying it 

 On the contrar)-, he has over and over again brought 

 the difficulties prominently forward. Nevertheless, 

 I doubt as little, now as heretofore, that the proba- 

 bilities are greatly in favour of our finding a way to the 

 causes of evolution by pertinacious study of variation 

 and natural selection. There are large fields for 

 inquiry open on all sides. How much has yet been 

 done, for example, towards ascertaining the eflfect of 

 external conditions on the struggle for existence within 

 the organism and the production of varieties as a 

 consequence of that struggle ; or towards an adequate 

 experimental study of variation? The supposition 

 that problems such as these, and others that might 

 easily be mentioned, could be finally solved, even in 

 thirty-five years, is one that would not enter the mind 

 of a competent biologist : and the parade of the 

 mutual contradictions and the intrinsic weaknesses of 

 the hypotheses which, hitherto, have been more or 

 less tentatively propounded, as if they had anything 

 to do with the truth or falsehood of the doctrine 

 of evolution, should not be taken too seriously. 



T. H. Huxley. 



