4o6 



NA TURE 



[Augtist 25, 1887 



" And in the summary of the chapter, he remarks concerning 

 the adjustments in the same (juadruped, that ' the prolonged use 

 of all the parts, together with inheritance, will have aided in an 

 important manner in this co-adaptation' (p. 199): a remark 

 probably having reference to the increased massiveness of the 

 lower part of the neck ; the increased size and strength of the 

 thorax required to bear the additional burden ; and the increased 

 strength of the fore-legs required to carry the greater weight of 

 both. But now I think- that further consideration suggests the 

 belief that the entailed modifications are much more numerous 

 and remote than at first appears ; and that the greater part of 

 these are such as cannot be ascribed in any degree to the selection 

 of favourable variations, but must be ascribed exclusively to the 

 inherited effects of changed functions." 



The passage then proceeds to trace these modifications of 

 structure in detail ; showing that the changes in the fore-quarters 

 entail corresponding changes in the hind-quarters, which when 

 running "perform actions differing in one or another way and 

 degree from all the actions performed by the homologous bones 

 and muscles in a mammal of ordinary proportions, and from 

 those of the ancestral mammal which gave birth to the giraffe." 

 Thus it is shown that bones, muscles, blood-vessels, nerve>, and 

 indeed nearly all the constituent structures of the body, have 

 everywhere been more or less modified as to relative size and 

 function, in order to adapt the giraffe as a whole to the unusual 

 development of its neck : this unusual development has entailed 

 changes, and changes, and counter-changes, which have eventually 

 spread throughout the whole organisation of the animal. 



Now, it appears to me that we have in this a most cogent 

 argument in favour of the inherited effects of use and disuse. 

 For, seeing how immense must be the sum of the organic 

 changes required to produce this mutual co-adaptation of many 

 structures, the chances against their all happening to occur to- 

 gether by way of fortuitous variation must be, as Mr. Spencer 

 observes, infinity to one. Yet unless they all did occur together 

 in the same organism — and this repeatedly — the co-adaptations 

 in question cannot have been due to natural selection. 



With more or less success Mr. Spencer develops several other 

 lines of argument ; but as they cannot well be reproduced without 

 occupying more space than can here be allowed, I will conclude 

 by adding to his material yet another consideration which appears 

 to me to be entitled to great weight. When we search through 

 the animal kingdom, we meet with certain instincts which cannot 

 reasonably be supposed to subserve any such life-preserving 

 function as that which has led to the survival, through natural 

 selection, of instincts in general. Now the existence of instincts 

 which are thus not of vital importance to the species presenting 

 them can only be explained by the hereditary effects of function. 

 For instance, it is difficult to suppose that the instinct, which is 

 still inherited by our domesticated dogs, of turning round and 

 round to trample down a comfortable bed before lying down, 

 can ever have been of so life-preserving a character as to have 

 been developed by survival of the fittest. Or, if this instance 

 be held doubtful, uhat shall we say to the courting instincts in 

 general, and to the play-instincts of the bower-bird in par- 

 ticular, which are surely quite without meaning from any 

 utilitarian point of view ? And these instincts naturally lead on 

 to the aesthetic faculties of mankind, few of which can be possibly 

 ascribed to natural selection, as Mr. Spencer very conclusively 

 shows. 



And here it becomes needful again to say a few words on 

 Prof. Weismann's essay, by way of criticism. For he, too, has 

 there considered the case of instincts, but this in a manner which 

 can scarcely be termed fortunate. For example, he particularly 

 instances the case of hereditary fear of enemies as one which 

 supports his argument against the inheritance of functionally-pro- 

 duced modifications. Now, this happens to be one of the 

 instincts which I have elsewhere specially chosen as yielding par- 

 ticularly good proof of the hereditary transmission of individual 

 experience, apart from natural selection. And the proof consists 

 merely in showing, from abundant testimony, that " the original 

 tameness of animals in islands unfrequented by man gradually 

 passes into an hereditary instinct of wildness as the special 

 experiences of man's proclivities accumulate ; and that such 

 instinctive adaptation to newly developing conditions may take 

 place without much aid from selection is shown by the short time, 

 or the small number of generations, which is sufficient to allow 

 for the change." i But although I think that Prof. Weismann's 

 selection of this instinct is a paiticularly unfortunate one for the 



" Mental Evolution in Animals," p. 197, where see for evidence. 



purpose of showing that its acquisition can on/y be due to 

 natural selection, I quite agree with him in holding that its de- 

 generation in our domesticated animals is due to the withdrawal 

 of natural selection — at leajt in considerable part. 



Again, he argues that if acquired mental proclivities are ever 

 inherited we should expect the human infant, without any 

 individual instruction, to converse. For, he argues, ever since 

 man became human he has been a talking anima', and there- 

 fore, if there were any truth in the view that knowledge acquired 

 by individuals tends to be transmitted to their progeny, here is 

 a case where the fact ought to admit of abundant proof: yet 

 every child requires to be taught its mother- tongue by its own 

 individual experience. 



Now, without waiting to show the manifest unfairness of this 

 example — seeing how enormously complex a system of cerebral 

 relations the speaking of even the simplest language implies— it 

 is enough for our present purposes to observe that language has 

 been itself the product of an immensely prolonged and highly 

 elaborate evolution. Although it is true that man has always 

 been a talking animal, it is very far from true that he has abjjays 

 talked the same lattguage. As a mat:er of fact, he has talked in 

 thousands of different languages, and if the genetic history of any 

 one of them could now be traced back to its original birth, the 

 probability is that it would be found to have passed through 

 some hundreds of phases, no one of which would have been fully 

 intelligible to the generations which spoke the others. Conse- 

 quently, even if we were to adopt the impossible supposition that 

 any length of time could be sufficient to enable heredity to 

 elaborate so huge an amount of instinctive acquisition as would 

 be required to render the knowledge of any language intuitive, 

 there would still remain this answer to Prof. Weismann — 

 namely, that if a child conld talk by instinct, it would require to 

 astonish its parents by addressing them in at least a hundred 

 unknown tongues, before arriving at the one which alone they 

 could understand. 



So much, then, by way of answer to Prof. Weismann's 

 supposed difficulty. But the matter does not end even here ; 

 for if he had searched the whole range of human faculties 

 he could scarcely have found a worse example to quote in 

 support of his argument, seeing that it admits of being turned 

 against that argument with the most overwhelming effect. This 

 argument is that the fact of speech not being instinctive is proof 

 that acquired knowledge is not transmitted. Now, we have just 

 seen it to be manifestly impossible that so elaborate, as well as so 

 recent, a body of acquired knowledge should be transmitted — 

 even though it were true that many instincts had been evolved in 

 this way. Nevertheless, it might still be reasonably objected 

 — as, indeed, Weismann says— that the simpler features which 

 serve to characterise all spoken languages alike, and m hich, there- 

 fore, have always constituted the common elements of language 

 as such — it might reasonably be urged that these simpler elements 

 which are thus common to all languages might well be expected 

 by this time to have become instinctive, if there is any truth at all 

 in the Lamarckian doctrine of the inherited effects of continuous 

 function. Bid this is exactly what we find. The only elements that 

 are common to all languages are the simplest elements of articu- 

 lation ; and it is now established beyond doubt that the human 

 infant is endowed with the instinct of making articulate sounds. 

 Long before the powers of understanding are sufficiently advanced 

 to admit of the child making any rational use of language, he 

 begins to babble meaningless syllabic utterances. And although 

 these utterances are extremely simple when contrasted with the 

 enormous complexity which they are soon destined to attain in 

 intelligible speech, yet, regarded in themselves, or as merely 

 hereditary endowments, the evolution of mechanism which they 

 represent is by no means contemptible. For they necessitate 

 highly peculiar as well as highly co-ordinated movements of the 

 laiynx, tongue, lips, and respiratory muscle-, not to speak of the 

 special innervation which all this requires, or the yet more 

 special cerebral conformation which it betokens. In short, the 

 illustration of spoken language, far from making against the 

 doctrine of Lamarck, is one of the best illustrations that can be 

 adduced in its favour ; for sui-ely it is in itself a most significant 

 fact that the young of the only talking animal should alone pre- 

 sent the instinct of making articulate sounds — ^just as it also alone 

 presents the instinct of alternately placing one leg before the 

 other, in a manner suited to walking in an erect position. 



Upon the whole, then, I conclude that the effects of use and 

 disuse are certainly inherited ; that the reducing influences of the 

 latter are largely assisted by the cessation of selection ; that the 

 cessation of selection is itself assisted by the economy of growth. 



