November 12, 1891] 



NATURE 



31 



varieties of protectively coloured insects are frequently confined to 

 very limited areas. Some will only be found on a certain species 

 of tree or plant ; others only on rocks or a stone wall of some 

 particular colour ; others, again, only on small patches of soil or 

 gravel ; while a short distance from these there may be other 

 objects diflferently marked, which may be frequented by insects 

 altogether different in colour, although belonging to the same or 

 to an allied species. Are we to suppose that every tree, plant, 

 rock, every stone wall, and every distinctive patch of soil or 

 gravel, has been the scene of natural selection ? There is no other 

 conclusion open to the Darwinist. But when it is considered 

 that natural selection may take hundreds of thousands or even 

 millions of years, to effect a given result, the strain upon our 

 forbearance must be great when we are asked to believe that 

 this process is the only one we have to reckon with. If the 

 phenomena can be accounted for by a shorter or simpler process, 

 why should the longer and more complex one be insisted on ? Is 

 it not more reasonable to suppose that animals have sufficient 

 intelligence to fly to, and remain in, the place where experience 

 has shown they are least exposed to observation? Can anyone 

 doubt that animals possess such knowledge? How otherwise are 

 we to explain the action of the butterfly, for instance, in darting 

 at once when disturbed to some object which resembles itself, 

 and then lying perfectly still, when one might in vain attempt to 

 find it, although within a few inches of it ? 



This view also receives corroboration from the fact that many 

 unprotected animals render themselves inconspicuous by 

 covering themselves with materials which resemble their environ- 

 ment. Thus certain Lepidopterous larvae form cases for 

 themselves out of the fragments of the substance on which they 

 feed, the ca<;es of the larvae of the Psychida;, for instance, being 

 made of leaves or of brown grass stems ; those of the Essex 

 emerald moth of fragments of leaves spun together with silk ; 

 certain species of sea-urchins and many Mollusca cover themselves 

 with grains of sand, shell, and bits of stone, while, according to 

 Poulton, certain species of crabs fasten species of seaweed to 

 their bodies for the same purpose. 



Topical selection will also explain the protective coloration of 

 certain vertebrates, as rabbits, hares, and deer. Thus Mr. H. 

 A. Brydon, who has an extensive acquaintance with the habits 

 of deer in South Africa, writes ("Kloof and Karoo," p. 298) as 

 follows : — 



" In some localities where the ' zuur veldt ' clothes the upper 

 parts of the mountains, and the ' rooi ' grass the lower portions, 

 the vaal and the rooi rhebok may be found on the same mountain- 

 side, but each adhering to its own peculiar pasturage. When 

 the hunters come upon the ground to shoot, the rooi rhebok 

 immediately fly from their lower slopes to the higher ground of 

 their grey brethren, and the two species are seen galloping in 

 close company over the mountain heights. If the hunter rests 

 quietly after his shot and looks about him, he will presently 

 see the two kinds of antelope, as soon as they think they may 

 5afely do so, separating, the rooi rhebok quitting the 'vaal' 

 pastures, and betaking themselves again to their own feeding- 

 grounds. To this habit they invariably adhere, and will not 

 delay their departure an instant longer than their safety admits 

 of. If the vaal rhebok in turn are driven out of their own 

 ground, they pursue exactly the same tactics, and will on 

 no account remain for long in their red brethren's territory." 



The occurrence of so many trimorphic and polymorphic 

 varieties of the same species have always been a puzzle to 

 Darwinists, as the numerous varieties which the Darwinian 

 theory postulates would all be killed off by natural selection, 

 except the "fit"; but according to the theory which I have 

 advanced, most variations would find their appropriate environ- 

 ments and live. If this theory of topical selection be correct, 

 its application to the phenomena of mimicry is obvious. We 

 have only to suppose that one animal may find safety in 

 associating with another animal to which it has some resem- 

 blance, without invoking the aid of either mimicry or natural 

 selection. 



I shall not attempt to reply to the other remarks of your critic 

 further than this, that no one who contents himself with read- 

 ing Dr. Wallace's review will be able to form the slightest idea 

 of the views put forth in my book. That it has taken a lifetime, 

 as Dr. Wallace correctly enough says it has, to build up " the 

 vast edifice" of Darwinism is surely no guarantee of the truth 

 of that system, and certainly no reason why it should be above 

 criticism, as my reviewer seems to think it should be. 



Melbourne, 1891. David Syme. 



NO. II 50, VOL. 45] 



Mr. Syme now says: "The references to Darwin in my 

 book are absolutely correct," and — "In every reference to 

 Darwin's views I gave the page and the edition from which the 

 quotation was taken." Assertions, however, are not proof-; ; 

 but if Mr. Syme will point out where Darwin defines natuial 

 selection as "the struggle for existence,"' and where Darwin 

 "insists that variations are created by natural selection," state- 

 ments which occur at p. 8 and p. 15 of Mr. Syme's book, I 

 will acknowledge that I have misrepresented him. Otherwise 

 I see nothing that requires modification in my article. But as 

 Mr. Syme claims to have taken "the utmost pains" to quote 

 Darwin's exact words, I will refer to other cases. At p. 12 he 

 says, " The second assumption is that favourably modified 

 individuals should be few in number, ' two or more ' ; " and for 

 this he refers to "Plants and Animals under Domestication," 

 vol. ii. p. 7. The true reference is to vol. i. p. 7, where Darwin 

 says : " Now, if we suppose a species to produce two or more 

 varieties, and these in course of time to produce other varieties, 

 &c." Here we see that Mr. Syme puts "individuals" in 

 the place of "varieties," and thus makes Darwin appear to 

 say the exact reverse of his main contention, which is, that 

 ordinary variability occurring in large numbers of individual, 

 not single sports, are the effective agents in the modification of 

 species. 



Again, at p. 102, Mr. Syme says, when discussing cross- 

 fertilization and variability : " No doubt self-fertilization is a 

 great factor in producing uniformity of colour. That this 

 uniformity is not due to the plants having been ' subjected 10 

 somewhat diversified conditions,' as Darwin intimates, is shown 

 by the fact, &c." But Darwin, as every student knows, saul 

 exactly the reverse of this — that the somewhat diversified con- 

 ditions produced variability ; and Mr. Syme's great efforts to 

 understand him and to quote him correctly again fail of succes?. 



One more example is to be found at p. no, where he says : 

 "Darwin has distinctly laid down the principle that if it can 

 be proved, by a single instance, that one organism exists for 

 the benefit of another organism, his whole system would fall to 

 the ground." But the statement made by Darwin was, that if 

 any part of the structure of one species could be proved to have 

 been formed for the exclusive good of another species it would 

 annihilate his theory ("Origin," 6th edition, p. 162). Mr. Syme 

 omits the essential word "exclusively," and thus appears to have 

 a strong case against the theory. 



As an example of general misrepresentation, I will refer to 

 p. 86, where Mr. Syme states that " the Darwinist " "carefully 

 ignores the facts which point in the opposite direction " (of the 

 necessity for insect fertilization of flowers) ; and on the next page, 

 after referring to cleistogamic and other self-fertilized flowers, 

 he asks: "Why does the Darwinist omit mention of such 

 structures as these ? " But he does not refer us to the Darwinists 

 in question who, while discussing insect fertilization, "carefully 

 ignore" self-fertilization; and as his statement will be taken to 

 include all, or at least the majority of Darwinists, it must beheld, 

 by those who are acquainted with the facts, to be a very absmd 

 misrepresentation. 



Other examples might be given, but these are sufficient to 

 support my statement that Mr. Syme has both misquoted and 

 misrepresented Darwin. 



The exposition of his theory of " topical selection" to explain 

 the phenomena of mimicry, as given above, may be left to the 

 judgment of the readers of Nature. 



Alfred R. Wallace. 



PROF. PICTETS LABORATORY AT BERLIN. 



IT has often been remarked that purely scientific re- 

 search frequently bears fruit of practical value. A fresh 

 illustration of this fact is afforded by the work of Prof. 

 Pictet, the eminent man of science of Geneva, who is 

 turning to practical account the apparatus by which, in 

 1877, he first reduced hydrogen and oxygen to the liquid 

 state. At Berlin, where he now resides, he has estab- 

 lished, on the scale of a small factory, what he terms a 

 " laboratoire ^ basses temperatures." The following ac- 

 count of the work carried on and the results obtained is 

 taken from papers read by the Professor before different 

 scientific Societies of Berlin. 

 The refrigerating machinery, driven by several powerful 



