[1] Part I, pp. 253-256.

[2] Contributions to the Theory of Natural Selection, p. 47.

[3] So far as we shall be concerned with them throughout this treatise, the "Lamarckian factors" consist in the supposed transmission of acquired characters, whether the latter be due to the direct influence of external conditions of life on the one hand, or to the inherited effects of use and disuse on the other. For the phrase "inherited effects of use and disuse," I shall frequently employ the term "use-inheritance," which has been coined by Mr. Platt Ball as a more convenient expression.

[4] Origin of Species, 6th ed. p. 8.

[5] Variation &c. 2nd ed. ii. p. 280.

[6] Variation &c. ii. p. 367.

[7] Origin of Species, p. 176.

[8] This, to the best of my judgement, is the fairest extract that I can give of Mr. Wallace's most recently published opinions on the points in question. [In particular as regards (a) see Darwinism pp. 435-6.] But with regard to some of them, his expression of opinion is not always consistent, as we shall find in detail later on. Besides, I am here taking Mr. Wallace as representative of the Neo-Darwinian school, one or other prominent member of which has given emphatic expression to each of the above propositions.

[9] Life and Letters, vol. iii. pp. 72 and 75.

[10] Take, for example, the following, which is a fair epitome of the whole:—"I believe that this is the simplest mode of stating and explaining the law of variation; that some forms acquire something which their parents did not possess; and that those which acquire something additional have to pass through more numerous stages than their ancestors; and those which lose something pass through fewer stages than their ancestors; and these processes are expressed by the terms 'acceleration' and 'retardation'" (Origin of the Fittest, pp. 125, 226, and 297). Even if this be "the simplest mode of stating the law of variation," it obviously does nothing in the way of explaining the law.

[11] Floral Structures (Internat. Sc. Ser. lxiv. 1888): The Making of Flowers (Romance of Science Ser. 1891); and Linn. Soc. Papers 1893-4.

[12] "The law of correlation," and the "laws of growth," he does recognize; and shows that they furnish an explanation of the origin of many characters, which cannot be brought under "the law of utility."

[13] Natural Selection and Tropical Nature, p. 205; 1891.

[14] Ibid. pp. 197-8.

[15] For an excellent discussion on the ontogeny of the child in this connexion, see Some Laws of Heredity, by Mr. S. S. Buckman, pp. 290, et seq. (Proc. Cotteswold Nat. Field Club, vol. x. p. 3, 1892).

[16] loc. cit. p. 198.

[17] For a discussion of this remarkable case, see Mental Evolution in Animals, pp. 222-3. It appears to me that if Mr. Wallace's argument from the "latent capacities of the voice of Man" is good for anything, a fortiori it must be taken to prove that, in the case of the Parrot, "the organ has been prepared in anticipation" of the amusement which the cultivation of its latent capacities arouses in "civilized man."

[18] Descent of Man, 1st Ed. ch. xx. (Trans. Dev. Assoc. for Science, 1890).

[19] The late Prof. Moseley informed me that, during his voyage on the Challenger, he had seen many men whose backs were well covered with hair.—For an excellent discussion of the whole question, chiefly in the light of embryology, see the paper by Buckman already alluded to, pp. 280-289. Also, for an account of an extraordinary hairy race of men, see Alone with the Hairy Ainu, by A. H. Savage Landor, 1893.

[20] E.g. "The special faculties we have been discussing clearly point to the existence in man of something which he has not derived from his animal progenitors—something which we may best refer to as being of a spiritual essence or nature, capable of progressive development under favourable conditions. On the hypothesis of this spiritual nature, superadded to the animal nature of man, we are able to understand much that is otherwise mysterious or unintelligible in regard to him, especially the enormous influence of ideas, principles, and beliefs over his whole life and action. Thus alone can we understand the constancy of the martyr, the unselfishness of the philanthropist, the devotion of the patriot, the enthusiasm of the artist, and the resolute and persevering search of the scientific worker after nature's secrets. Thus we may perceive that the love of truth, the delight in beauty, the passion for justice, and the thrill of exultation with which we hear of any act of courageous self-sacrifice, are the workings within us of a higher nature which has not been developed by means of the struggle for material existence." (Darwinism, p. 474.) I have quoted this whole paragraph, because it is so inconsistent with the rest of Mr. Wallace's system that a mere epitome of it might well have been suspected of error. Given an intellectual being, howsoever produced, and what is there "mysterious or unintelligible" in "the enormous influence of ideas, principles, and beliefs over his whole life and action"? Or again, if he be also a social being, what is the relevancy of adducing "the constancy of the martyr," "the unselfishness of the philanthropist," "the devotion of the patriot," "the love of truth," "the passion for justice," "the thrill of exultation when we hear of any act of courageous self-sacrifice," in evidence against the law of utility, or in order to prove that a "nature" thus endowed has "not been developed by means of the struggle for existence," when once this struggle has been transferred from individuals to communities? The whole passage reads like an ironical satire in favour of "Darwinism," rather than a serious argument against it.

[21] See Proc. Zool. Soc. June 4, 1889, for an account of the performances in this respect of the Chimpanzee "Sally." Also, for some remarks on the psychology of the subject, in Mental Evolution in Man, p. 215. I should like to take this opportunity of stating that, after the two publications above referred to, this animal's instruction was continued, and that, before her death, her "counting" extended as far as ten. That is to say, any number of straws asked for from one to ten would always be correctly given.

[22] In Prof. Lloyd Morgan's Animal Life and Intelligence there is an admirable discussion on this subject, which has been published since the above was written. The same has to be said of Weismann's Essay on Music, where much that I have here said is anticipated. With the views and arguments which Mr. Mivart has forcibly set forth I have already dealt to the best of my ability in a work on Mental Evolution in Man.

[23] American Naturalist, xxii. pp. 201-207.

[24] It is almost needless to say that besides the works mentioned in this chapter, many others have been added to the literature of Darwinism since Darwin's death. But as none of these profess to contain much that is original, I have not thought it necessary to consider any of them in this merely general review of the period in question. In subsequent chapters, however, allusions will be made to those among them which I deem of most importance.

[Since this note was written and printed the following works have been published to which it does not apply: Animal Life and Intelligence, by Professor Lloyd Morgan; The Colours of Animals, by Professor Poulton; and Materials for the Study of Variation, by Mr. Bateson. All these works are of high value and importance. Special reference should also be made to Professor Weismann's Essays.]

[25] Originally, Weismann's further assumption as to the perpetual stability of germ-plasm, "since the first origin of sexual reproduction," was another very important point of difference, but this has now been withdrawn.

[26] I say "mainly formed anew," and "for the most part interrupted," because even Darwin's theory does not, as is generally supposed, exclude the doctrine of Continuity in toto.

[27] Theory of Heredity (Journ. Anthrop. Inst. 1875, p. 346).

[28] Mr. Platt Ball has, indeed, argued that "use-inheritance would often be an evil," since, for example, "the condyle of the human jaw would become larger than the body of the jaw, because as the fulcrum of the lever it receives more pressure"; and similarly as regards many other hypothetical cases which he mentions. (The Effects of Use and Disuse, pp. 128-9 et seq.) But it is evident that this argument proves too much. For if the effects of use and disuse as transmitted to progeny would be an evil, it could only be because these effects as they occur in the parents are an evil—and this they most certainly are not, being, on the contrary and as a general rule, of a high order of adaptive value. Moreover, in the race, there is a superadded agency always at work, which must effectually prevent any undue accumulation of these effects—namely, natural selection, which every Darwinist accepts as a controlling principle of all or any other principles of change. Therefore, if, as first produced in the life-time of individuals, the effects of use and disuse are not injurious, much less can they become so if transmitted through the life-time of species. Again, Mr. Wallace argues that, even supposing use-inheritance to occur, its adapting work in the individual can never extend to the race, seeing that the natural selection of fortuitous variations in the directions required must always produce the adaptations more quickly than would be possible by use-inheritance. This argument, being one of more weight, will be dealt with in a future chapter.

[29] Variation under Domestication, ii. 392.

[30] In subsequent chapters, especially devoted to the question (i.e. Section II), the validity of this assumption will be considered on its own merits.

[31] I say "the followers of Weismann," because Weismann himself, with his clear perception of the requirements of experimental research, expressly states the above considerations, with the conclusions to which they lead. Nevertheless, he is not consistent in his utterances upon this matter; for he frequently expresses himself to the effect, "that the onus probandi rests with my opponents, and therefore they ought to bring forward actual proofs" (Essays, i. p. 390). But, as above shown, the onus rests as much with him as with his opponents; while, even if his opponents are right, he elsewhere recognizes that they can bring "actual proofs" of the fact only as a result of experiments which must take many years to perform.

[32] Note A.

[33] For a fair and careful statement of the present balance of authoritative opinion upon the question, see H. F. Osborn, American Naturalist, 1892, pp. 537-67.

[34] [The above paragraph is allowed to remain exactly as Mr. Romanes left it. Chapters V and VI were however not completed. See note appended to Preface. C. Ll. M.

[35] See, especially, his excellent remarks on this point, Contemp. Rev. Sept. 1893.

[36] There is now an extensive literature within this region. The principal writers are Cope, Scott and Osborn. Unfortunately, however, the facts adduced are not crucial as test-cases between the rival theories—nearly all of them, in fact, being equally susceptible of explanation by either.

[37] For another and better illustration more recently published by Mr. Spencer, see The Inadequacy of Natural Selection, p. 22.

[38] Essays on Heredity, vol. i. p. 389.

[For further treatment of the subject under discussion see Weismann, The All-sufficiency of Natural Selection (Contemp. Rev. Sept. and Oct. 1893), and The Effect of External Influences upon Development. "Romanes Lecture" 1894, and Spencer, Weismannism once more (Cont. Rev. Oct. 1894). C. Ll. M.]

[39] Variation, &c., vol. ii. p. 206.

[40] E. g. Origin of Species, p. 178.

[41] Darwinism, p. 418.

[42] Nature, vol. xliii. pp. 410, 557; vol. xliv. pp. 7, 29. I say "adopted," because I had objected to his quoting the analogy of artificial selection, and stated, as above, that the only way to meet Mr. Spencer's "difficulty" was to deny the fact of co-adaptation as ever occurring in any case. It then appeared that Professor Meldola agreed with me as to this. But I do not yet understand why, if such were his view, he began by endorsing Mr. Wallace's analogy from artificial selection—i. e. confusing the case of co-adaptation with that of the blending of adaptations. If any one denies the fact of co-adaptation, he cannot assist his denial by arguing the totally different fact that adaptations may be blended by free intercrossing; for this latter fact has never been questioned, and has nothing to do with the one which he engaged in disputing.

[43] It may be said, with regard to this particular reflex, that it may perhaps be, so to speak, a mechanical accident, arising from the contiguity of the sensory and motor roots in the cord. But as this suggestion cannot apply to other reflexes presently to be adduced, it need not be considered.

[44] Of course it will be observed that the question is not with regard to the development of all the nerves and muscles concerned in this particular process. It is as to the development of the co-ordinating centres, which thus so delicately respond to the special stimuli furnished by variations of angle to the horizon. And it is as inconceivable in this case of reflex action, as it is in almost every other case of reflex action, that the highly specialized machinery required for performing the adaptive function can ever have had its origin in the performance of any other function. Indeed, a noticeable peculiarity of reflex mechanisms as a class is the highly specialized character of the functions which their highly organized structures subserve.

[45] We meet with a closely analogous reflex mechanism in brainless vertebrata of other kinds; but these do not furnish such good test cases, because the possibility of natural selection cannot be so efficiently attenuated. The perching of brainless birds, for instance, at once refers us to the roosting of sleeping birds, where the reflex mechanism concerned is clearly of high adaptive value. Therefore such a case is not available as a test, although the probability is that birds have inherited their balancing mechanisms from their sauropsidian ancestors, where it would have been of no such adaptive importance.

[46] Pflüger's Archiv, Bd. xx. s. 23 (1879).

[47] Brain, part xlviii, pp. 516-19 (1889).—There is still better proof of this in the case of certain rodents. For instance, observing that rats and mice are under the necessity of very frequently scratching themselves with their hind-feet, I tried the experiment of removing the latter from newly-born individuals—i.e. before the animals were able to co-ordinate their movements, and therefore before they had ever even attempted to scratch themselves. Notwithstanding that they were thus destitute of individual experience with regard to the benefit of scratching, they began their scratching movements with their stumps as soon as they were capable of executing co-ordinated movements, and afterwards continued to do so till the end of their lives with as much vigour and frequency as unmutilated animals. Although the stumps could not reach the seats of irritation which were bent towards them, they used to move rapidly in the air for a time sufficient to have given the itching part a good scratch, had the feet been present—after which the animals would resume their sundry other avocations with apparent satisfaction. These facts showed the hereditary response to irritation by parasites to be so strong, that even a whole life-time's experience of its futility made no difference in the frequency or the vigour thereof.

[48] For details of his explanation of this particular case, for which I particularly inquired, see Mental Evolution in Animals, pp. 301-2.

[49] Note B.

[50] For fuller treatment see Mental Evolution in Animals, pp. 274-285, 378-379, 381-383.

[51] For an excellent essay on the deleterious character of early forms of religion from a biological point of view, see the Hon. Lady Welby, An Apparent Paradox in Mental Evolution (Journ. Anthrop. Inst. May 1891).

[52] Essays, i. p. 93.

[53] See Mental Evolution in Animals, pp. 377-8.

[54] [See H. Spencer, The Inadequacy of Natural Selection, A Rejoinder to Professor Weismann, Contemp. Rev. 1893; and Weismannism once more, Ibid. Oct. 1894; Weismann, The All-sufficiency of Natural Selection, Ibid. 1893; and The Effect of External Influences upon Development, "Romanes Lecture" 1894: also Neuter Insects and Lamarckism, W. Platt Ball, Natural Science, Feb. 1894, and Neuter Insects and Darwinism, J. T. Cunningham, Ibid. April 1894. C. Ll. M.]

[55] Variation of Plants and Animals, vol. ii. p. 289.

[56] Ibid. p. 346.

[57] Essays, i. p. 90.

[58] Nature, vol. ix. pp. 361-2, 440-1; and vol. x. p. 164.

[59] Appendix I.

[60] For a fuller statement of Mr. Galton's theory of Heredity, and its relation to Weismann's, see An Examination of Weismannism.

[61] For a fuller explanation of the important difference between the mere cessation and the actual reversal of selection, see Appendix I.

[62] Animal Life, International Scientific Series, vol. xxxi.

[63] The experiments of Galton and Weismann upon this subject are nugatory, as will be shown later on. But since the above was written an important research has been published by Mr. Cunningham, of the Marine Biological Association. For a full account I must refer the reader to his forthcoming paper in the Philosophical Transactions. The following is his own statement of the principal results:—

"A case which I have myself recently investigated experimentally seems to me to support very strongly the theory of the inheritance of acquired characters, I have shown that in normal flat-fishes, if the lower side be artificially exposed to light for a long time, pigmentation is developed on that side; but when the exposure is commenced while the specimens are still in process of metamorphosis, when pigment-cells are still present on the lower side, the action of light does not prevent the disappearance of these pigment-cells. They disappear as in individuals living under normal conditions, but after prolonged exposure pigment-cells reappear. The first fact proves that the disappearance of the pigment-cells from the lower side in the metamorphosis is an hereditary character, and not a change produced in each individual by the withdrawal of the lower side from the action of light. On the other hand, the experiments show that the absence of pigment-cells from the lower side throughout life is due to the fact that light does not act upon that side, for, when it is allowed to act, pigment-cells appear. It seems to me the only reasonable conclusion from these facts is, that the disappearance of pigment-cells was originally due to the absence of light, and that this change has now become hereditary. The pigment-cells produced by the action of light on the lower side are in all respects similar to those normally present on the upper side of the fish. If the disappearance of the pigment-cells were due entirely to a variation of the germ-plasm, no external influence could cause them to reappear, and, on the other hand, if there were no hereditary tendency, the colouration of the lower side of the flat-fish when exposed would be rapid and complete."—Natural Science, Oct. 1893.