June 12, 1879] 



NATURE 



143 



tion to one of the most original thinkers of the first half 

 of the 19th century. 



The last four chapters of the work are devoted to a 

 critical comparison of the theories of Mr. Darwin with 

 those of Lamarck, Dr. Darwin, and Buffon, greatly to the 

 disadvantage (in Mr. Butler's opinion) of the former. 

 Much of this criticism, however, is merely verbal, and is 

 quite valueless ; much of it, also, is founded on a con- 

 fusion as to the meaning of such terms as "variation" 

 and "variety," and on an inability to grasp the fact of 

 the extent and universality of the individual variations of 

 organisms ; while another portion arises from taking the 

 hypotheses of Lamarck as established facts. Of these 

 several classes of unsound criticism we will give a few 

 examples. 



Mr. Butler first quotes (p. 339) numerous expressions 

 from the "Origin of Species," referring to our great 

 ignorance of the laws of variation, and our total ignorance 

 of the cause of each individual difference ; and then speaks 

 of Lamarck " having established his principle that sense of 

 need is the main direct cause of variation," and that 

 variations thus engendered are inherited, which sufficiently 

 accounts for all the facts. If Lamarck had " established " 

 anything of the kind, Mr. Darwin and all evolutionists 

 would certainly have followed him, but he nowhere proves 

 or even attempts to prove his "principle," but merely 

 states it as an "hypothesis" to account for facts which 

 he saw no other way of explaining. Again, Mr. Butler 

 himself says, that owing to the conditions of life being 

 permanent for long periods — "The thoughts of the creature 

 varying will thus have been turned mainly in one direc- 

 tion for long together ; and hence the consequent modifi- 

 cations will also be mainly in fixed and definite directions 

 for many successive generations ; as in the direction of a 

 warmer or cooler covering, <S:c. ... It is easy to under- 

 stand the accumulation of slight successive modifications 

 ■which thus make their appearance in giveti organs and in 

 a set direction." The passages which I have italicised 

 look like statements of fact — of what actually occurs ; yet 

 no such facts have ever been made known. If the law 

 thus stated had been sufficiently effective to produce any 

 permanent variations, breeders would sometimes have 

 made use of it. Yet they certainly do not do so, whereas 

 they do systematically and very successfully make use of 

 selection. According to the above theory Australian 

 sheep must have their thoughts constantly turned in the 

 direction of less wool owing to the great heat of the climate 

 and a much larger proportion of each succeeding genera- 

 tion should have thin and scanty fleeces than occurs in 

 England, especially in the tropical colony of Queensland 

 which, in proportion to its population, produces as much 

 wool as the other colonies. If Mr. Butler could adduce, 

 on good authority, such a fact as this, he would have 

 some evidence in his favour, instead of which he can only 

 make suppositions. The fantail and pouter pigeons, the 

 crested Poland fowls, and all other strange domestic 

 varieties, have been produced by selection of variations 

 or sports which occurred among animals all subject to 

 the same tolerably uniform conditions ; while no proof 

 has ever been given that anything more than very slight 

 changes can be produced and perpetrated by change of 

 conditions unaided by some kind of selection, 



Mr. Butler's want of appreciation of what variation and 



natural selection really are, is shown by his referring to 

 "the fact that one in a brood or litter, is born fitter for the 

 conditions of existence than its brothers and sisters" — by 

 his continually laying stress upon Mr. Darwin not having 

 shown "how the individual differences first occur" — by 

 his thinking that because natural selection is not the 

 cause of "variation" it is therefore not the cause of 

 "modification" or of a "variety" or "species "—and 

 by his hardly ever referring to the enormous multiplying 

 powers of animals, and the consequent extermination of 

 a much greater number annually than the whole average 

 living population. In my former article on the works of 

 Mr. Murphy and Mr. Butler (Nature, vol. xix. p. 477) I 

 have shown how we may look at the whole population of 

 a species at any given time as divisible, with regard to 

 any one of its characters, into a more and a less deve- 

 veloped moiety, and I believe that this mode of viewing 

 the question will at once almost entirely remove the co- 

 incident-variation-in-the-right-direction difficulty, which 

 forms the great stumbling-block of almost all the oppo- 

 nents of Mr. Darwin. 



The difficulty as to the " cause of variation " also dis- 

 appears from this point of view, for " variation " is seen 

 to be synonymous with " want of perfect identity " be- 

 tween any two organisms, and this is clearly due to the 

 almost infinite complexity of structure and minuteness of 

 parts of all living things and the absolute impossibility 

 that any two can have passed through an identical series 

 of conditions or even had an origin in two identical germs. 

 We see infinite variety arise in the inorganic world where 

 there is a far less complexity of structure or variety of 

 conditions. Even among the sands on the sea-shore no 

 two grains are probably so nearly identical that a good 

 microscopist could not detect a difference ; while it is 

 certain that nowhere in the world are there two hills or 

 two rivers with any approach to complete similarity, 

 though the entire process by which many of them have 

 been produced must have often been almost identical. 

 Variation, such as always occurs between the individuals 

 of a species, is therefore an ultimate fact of nature which 

 wants no further explanation than that we cannot even 

 conceive it to be otherwise. We may indeed conceive 

 more likeness on the average than actually exists, but we 

 cannot really conceive of perfect identity between indi- 

 viduals formed and developed as are animals and plants. 

 We may, on the other hand, seek for the causes of 

 unusual or abnormal variation, and Mr. Darwin has 

 suggested several. It is quite possible that those sug- 

 gested by Lamarck and Mr. Butler may also be real 

 causes, but they have certainly not been proved to be so . 

 and even if they had they would not in the least affect 

 the law of natural selection which accumulates and 

 perpetuates variations, however they may have been 

 produced. 



The numerous verbal criticisms or quibbles in which 

 Mr. Butler indulges are quite unworthy of his subject. 

 When Mr. Darwin says, " Variation will cause the slight 

 alterations," Mr. Butler remarks that this is the same as 

 saying " Variation will cause the variations." Again, 

 Mr. Butler maintains that the term "conditions of ex- 

 istence " is identical with or includes " survival of the 

 fittest," which is identical with "natural selection." 

 Therefore, when Mr. Darwin says "natural selection is 



