478 



NATURE 



{March 27, 1879 



on which selection may work when variations of a parti- 

 cular kind are needed. 



The next three new chapters, on " Fixation of Characters," 

 on "Effect of Change of Conditions," and on "Mimicry, 

 Colour, and Sexual Selection," contain much interesting 

 matter, with a number of suggestions of difficulties mostly 

 dependent upon our total ignorance of the peculiar condi- 

 tions or laws under which certain characters first arose. 

 Such difficulties are of little importance, because they are 

 always liable to disappear with an increase of knowledge. 

 What, for instance, is the value of such a criticism as 

 this : " The abnormal position of the left carotid artery 

 in some groups of parrots is as good an instance as can be 

 mentioned of a character which is constant throughout 

 an entire group, which must have arisen suddenly, and 

 cannot have been fixed by natural selection, because it 

 cannot be useful." The three words I have italicised 

 mark three positive statements which cannot possibly be 

 verified, and which may very probably all be wrong. The 

 parrots form not 2, family only, but a very distinct order 

 of birds, and, from the occurrence in the miocene of 

 France of a parrot of a living'genus, are probably of im- 

 mense antiquity. Not only do we know nothing of their 

 early history, but, owing to their so rarely breeding in this 

 country we know nothing of their embryology, and can 

 therefore have no grounds for assertions as to what 

 could or could not have been in the remote past, when 

 they were developing into the varied forms that now exist, 

 under conditions of which we are perfectly ignorant. 



Another new chapter, on " Metamorphoses and Meta- 

 genesis" gives an interesting outline of the metamor- 

 phosis of insects, Crustacea, and hydroids, illustrated by a 

 number of excellent figures, and remarks on the difficulty 

 of explaining many of the facts by variation and natural 

 selection, the conclusion being that " many of the trans- 

 formations, especially among the Crustacea and the 

 hydrozoa, do not consist in adaptations to any new or 

 special mode of life, and consequently cannot be accounted 

 for by the Darwinian or any similar theory, but must be 

 due to a formative impulse impressed on living matter at 

 the beginning." 



The next chapter, on " Structure in Anticipation of 

 Function," is not so good as some of the others, and here 

 again objections are brought forward whose whole weight 

 depends on our ignorance of the conditions under which 

 certain structures were modified. Thus, it is said to ap- 

 pear impossible to account for the transition from the fin 

 of Ceratodus to the simple fin-ray of Lepido siren by any 

 means which Darwinism admits, because it seems im- 

 possible that the loss of the membranes of its fins can be 

 beneficial to a fish. But in this case there seems to be a 

 difference of habits which may show how the " impossible" 

 occurred. The Lepidosiren of the Gambia burrows in the 

 mud, where it remains during the dry season, and for 

 this "burrowing" the cylindrical rays may be better 

 adapted than the broad fins of Ceratodus. 



In the chapter on the " Origin of Man " Mr. Murphy 

 replies to my argument that the brain of savage man is 

 an instrument beyond his needs, by pointing out that 

 "the real superiority of man consists in the faculty of 

 language, and that the mental power implied in this 

 unique faculty is represented by the very great excess in 



the size of the human brain over that of the highest 

 apes ; " and he goes on to say : "If, then, the Darwinian 

 theory is true of man, the difference between the highest 

 ape and that of the lowest man is due to the exercise of 

 the brain during the period while the power of language 

 was in process of evolution, aided by the natural selection 

 of the largest brains, in which, of course, this new power 

 would be most highly developed." This appears to me 

 a very forcible objection, and I must acknowledge that it 

 is "a sufficient answer " to my argument, so far as regards 

 the difference between the brain of savage man and apes. 

 The question remains, however, of the latent powers in 

 the brain of savages ; and Mr. Murphy maintains that 

 the languages of many savages — of the Kafirs, for 

 example, are so much in advance of their needs that they 

 could not have been evolved by natural selection. In 

 most other respects he agrees with the arguments in my 

 essay on " The Limits of Natural Selection as applied to 

 Man." 



This concludes the new matter in the physiological part 

 of the book ; but before passing on to the psychological 

 portion, I must notice one passage embodying a very 

 common source of confusion as regards the geographical 

 distribution and mode of origin of species. Referring to 

 the marine lizard of the Galapagos, Amblyrhynchus, Mr. 

 Murphy remarks : " This singular species is found no- 

 where except in the Galapagos, and consequently has, 

 most probably, been evolved there ; but on Darwinian 

 principles, how can so peculiar and aberrant a form have 

 been evolved during the geologically short time that has 

 passed since these islands first rose above the ocean ? " 

 The difficulty thus raised, with many analogous cases, I 

 have endeavoured to explain in the February issue of the 

 Nineteenth Century. The idea that this peculiar lizard 

 has been " evolved " in the Galapagos really implies 

 spontaneous generation ; for what was it evolved out of ? 

 A remote ancestral form must have reached the islands 

 from the main land, if there is to be any "evolution" in 

 the case, and if a remote why not a near ancestor ? It ap- 

 pears to me, not a mere probability but almost a certainty, 

 that the generic type, if not the actual species, was 

 "evolved" in America ; that it was once an abundant, 

 and, in fact, a dominant group ; that it then spread to 

 the Galapagos ; that the entire group then died out on 

 the main land, but was preserved in the islands, owing to 

 the absence of enemies and competitive forms. On this 

 principle almost all the supposed difficulties of geogra- 

 phical distribution may be rationally explained ; and this 

 mode of explanation is in accordance with palaeontological 

 evidence whenever it is procurable. 



The remaining chapters form the psychological part of 

 the work, in which the author develops his theory of the 

 organising intelligence in animal forms. The only new 

 chapter here is that on "Automatism," in which the 

 various questions connected with the automatic motions 

 of plants and animals, and with the instincts and the 

 habits of animals, are set forth and commented on ; and 

 here it is very interesting to compare the conclusions 

 arrived at with those of Mr. Butler in his very original 

 and suggestive book on " Life and Habit." 



Mr. Murphy says that the actions of a sea-anemone in 

 seizing on its prey with its tentacles, or in closing itself 



