June 24, 1909] 



NATURE 



material particulars since Darwin's days, and, if so, in 

 what direction and to what extent? Out of the con- 

 flictingf views on this fundamental point it is safe to 

 extract the jjencral conclusion that for the great 

 majority of living- biologists natural selection is still a 

 working power in organic evolution. Equally evident 

 must it be to those who weigh the evidence brought 

 together in these essays that the theory, as bequeathed 

 to us by its illustrious founder, has, to borrow certain 

 photographic terms, undergone in some directions 

 intensification and in other directions reduction. By 

 way of intensification we have the elimination of the 

 effects of " use and disuse " and of " direct action " 

 of the environment — the deletion by Weismann of all 

 the Lamarckian factors. It is sufficiently notorious 

 that Darwin attached a certain weight to these factors. 

 When, in 1862, Hooker was inclined to throw over 

 " direct effects of conditions," he wrote : — 



" It is really curiously satisfactory to me to see so 

 able a man as Bates (and yourself) believing more 

 fully in natural selection tlian I think I even do 

 myself " (" More Letters," vol. i., p. 199). 



The same point is well brought out by .Schwalbe in 

 the present volume (p. las)- ^'^^ by Haeckel (p. 141), 

 although it may well be doubted whether Darwin was 

 so much of a Lamarckian as Haeckel would make 

 out. But in accepting the Lamarckian factors as 

 subsidiary aids in the development of species, it must 

 not be forgotten, as has so frequently been pointed 

 out, that Darwin was only expressing the current 

 belief of the time. The efficiency of these factors in 

 producing individual modifications was an observed 

 fact, but their inheritance was an assumption. The 

 validity of this assumption was not challenged by 

 Weismann until after Darwin's death, and the master, 

 to our everlasting regret, never had an opportunity of 

 weighing the evidence brought against these factors 

 which he regarded as subsidiary. If it is permissible 

 to speculate as to the probable effect of Weismann 's 

 contention upon Darwin's " immortal work " 

 (Schwalbe, p. 125) and " epoch-making " volume 

 (Haeckel, p. 143), it may, perhaps, be admitted that 

 " the ' Origin ' without ' use and disuse ' would be 

 a materially different book " (Batcson, p. 89). But in 

 what way different? It may very well have transpired 

 that the views of its great author would have become 

 more rigidly " selectionist," as did those of Wallace 

 after he had considered and admitted the cogency of 

 (he arguments against the Lamarckian tenets. 



In view of the state of knowledge concerning 

 heredity at the time of the publication of the 

 " Origin," it may fairly be asked whether it is so 

 absurdly unscientific, as many opponents of natural 

 selection used to tell us, to extend the views of the 

 founder of a great principle beyond the limits foreseen 

 by their founder. The history of science furnishes 

 numerous examples of such developments. We never 

 heard it urged in scornful argument, for example, 

 against the electro-magnetic theorv of light that 

 Clerk-Maxwell had made himself ridiculous by be- 

 coming more of an " undulationist " than Young and 

 Fresnel. If, departing from Haeckel, who agrees 

 with Herbert Spencer in rejecting Weismann 's views 

 NO. 2069, VOL. 80] 



(p. 140), we follow Francis Galton, Wallace, Poulton, 

 Bateson (presumably, p. 89), and those who agree in 

 believing that Lamarckism is discredited, we strike 

 out a factor in species formation which " aided 

 [natural selection] in an important manner " 

 (" Origin," sixth edition, p. 421). The importance of 

 natural selection may — it does not logically follow 

 that it must — thereby be enhanced. It is perfectly 

 scientific, and quite in harmony with the spirit of the 

 great leader whose mind was ever open to fresh 

 evidence, to believe that not only has natural selection 

 stood the test of time, but that its author may have 

 under-estimated rather than exaggerated its import- 

 ance. This is the direction in which the theory has 

 undergone intensification. 



In the opposite direction and by way of reduction 

 we have a number of opinions which practically 

 amount to traversing Darwin's claim for natural 

 selection as the " main " factor. Some attach less 

 importance to it, some give it quite a subordinate 

 rule and a few almost appear to imply that it can be 

 dispensed with altogether : — 



" The discovery of de Vries that new species may 

 arise by mutation and the wide if not universal 

 applicability of Mendel's law to phenomena of 

 heredity, as shown especially by Bateson and his 

 pupils, must for the time being, if not permanently, 

 serve as a basis for theories of evolution " (Loeb, 

 p. 269). 



Perhaps the author of the above passage will not 

 admit that it bears this construction, but at any rate, 

 as an example of the reducing action exerted by a 

 certain class of modern workers, it seemed typical. 

 Darwin thought that he had given a working theory 

 which, if it did not completely solve, at least went a 

 very long way towards solving the problem of the 

 origin of species in nature. Bateson tells us 

 (P 99) :— 



" The time is not ripe for the discussion of the 

 origin of species. With faith in evolution unshaken — • 

 if indeed the word faith can be used in application to 

 that which is certain — we look on the manner and 

 causation of adapted differentiation as still wholly 

 mysterious." 



The " educated lavman "—if his sense of humour 

 has not been educated out of him— may possibly want 

 to know why, if the species question is to be thus 

 thrown into the melting-pot, the Cambridge 

 authorities thought it advisable to issue a volume to 

 commemorate " the fiftieth anniversary of the publica- 

 tion of the 'Origin of Species.'" It is, of course, 

 perfectly legitimate for any biologist who has con- 

 sidered the question to declare that he is dissatisfied 

 with the evidence on which Darwin based his claim 

 for the prepotency of natural selection — to bring in a 

 verdict of " not proven." That is a matter of indi- 

 vidual judgment on the evidence submitted. But in 

 giving this verdict, it must be clearly recognised that 

 he is taking a position diametrically opposed to that 

 of the author of the book which is being com- 

 memorated. It may be said, and is virtually said by 

 some of the contributors, that the claim to the com- 

 memoration of the " Origin " is not based upon the- 



