Part 12

The array of figures brought forward to prove that the _Leptalis_ could not have made twenty steps of variation in the direction of the _Ithomia by chance_, would be much to the purpose if any exponent of the theory of Natural Selection had ever argued or supposed that it could. The calculation takes it for granted that the theory is erroneous, instead of proving it to be in error. Upon this assumption, it might have been put far more strongly, only that a stronger way of putting it would have borne on the face of it the suspicion of some inherent fallacy. It begins by supposing that there are ‘twenty different ways in which a _Leptalis_ may vary, only one of these being in the direction ultimately required;’ it might quite as truthfully, or even more so, have said a thousand instead of twenty, and then the second step would have given the chance as only one in a million, instead of one in four hundred. But while the theory of Natural Selection speaks of numerous minute useful variations, Mr. Bennett will not allow that combination of terms. Let them be numerous and minute, if you will, he says; but if small, they cannot be useful; if useful, they cannot be small. He claims to have Mr. Darwin’s own word for it, that a large variation would not be permanent, as though Mr. Darwin had said, ‘living creatures have come to be what they are by successive useful deviations of structure permanently propagated, but no large deviations are permanent, and no small ones are useful.’ It is quite obvious that in the use of relative terms, such as great and small, Mr. Darwin neither intended to stultify himself nor has done so. A thing may be large enough to be useful without being large as compared with something twenty times its own size; and a man may be said to have a huge brain in a very small body, although the body in solid content far exceeds the brain. When Mr. Darwin says that ‘Natural Selection always acts with extreme slowness’, he does not imply that its steps must therefore be so numerous as to be too small to confer any advantage. This would be a contradiction in terms. But the steps may be exceedingly small notwithstanding, and also sometimes separated by enormous intervals of time from one another.

In introducing his own explanation of things, Mr. Bennett affirms that ‘resemblances, and resemblances of the most wonderful and perfect kind’ in the vegetable kingdom, ‘are in no sense mimetic or protective.’ This may be so, but it can hardly be said to be proved. When he speaks of ‘man’s reason’ having ‘assisted him so to modify his body as to adapt himself to the circumstances with which he is surrounded,’ and suggests that the instinct of animals may have assisted them also to modify their bodies by slow and gradual degrees to the same purpose, it is difficult to imagine the process intended, and still more difficult to see how ‘the slow and gradual degrees’ will escape the rigid test of mathematical calculation which Mr. Bennett has elsewhere applied; for if the steps are great, they ought not to be permanent; and if small, they ought not to be useful. A theory which makes it possible for a bee to ‘modify its proboscis’ by instinct, or for a man to treat his nose in the same manner by reason, seems harder of digestion than the Darwinian.

Torquay, Nov. 12, 1870.

THE GENESIS OF SPECIES.

A review in ‘Nature,’ by Mr. A. W. Bennett, of Mr. Mivart’s ‘Genesis of Species,’ contains the following passage:--

‘It behoves, therefore, every Darwinian to satisfy himself that either Mr. Mivart’s premisses or his line of argument is unsound.

‘The objections brought forward by the author are summed up as follows:--(1) That Natural Selection is incompetent to account for the incipient stages of useful structures. (2) That it does not harmonize with the coexistence of closely similar structures of diverse origin. (3) That there are grounds for thinking that specific differences may be developed suddenly instead of gradually. (4) That the opinion that species have definite though different limits to their variability is still tenable. (5) That certain fossil transitional forms are absent which might have been expected to be present. (6) That some facts of geological distribution supplement other difficulties. (7) That the objection drawn from the physiological difference between “species” and “races” still exists unrefuted. (8) That there are many remarkable phenomena in organic forms upon which Natural Selection throws no light whatever, but the explanations of which, if they could be attained, might throw light upon specific origination.

‘If these objections are not new, they are at least sustained by new arguments. They are evidently of very unequal value. The third is very difficult of proof or disproof. The fifth may be true in our present state of knowledge, but would be very unsafe by itself as the basis of an argument. The first, second, and eighth are of greatest value, and are those which Mr. Mivart has most closely worked out[68].’

The review containing the above passage did not appear till the present volume was on the very eve of publication. Even a hasty glance at Mr. Mivart’s book is sufficient to show that Mr. Bennett has not over-estimated its importance and value. It is scarcely possible here to do more than make a few reflections upon its general scope, in reply to the challenge offered to Darwinians. The first objection, as it stands in the summary, wears the appearance of a misconception. It is almost certain to produce one. When Mr. Darwin attributes the origin of species to Natural Selection, he includes expressly, and where not expressly, by obvious implication, the principle of Variability. He never maintains that the first or any subsequent stage of a useful structure can be produced by Natural Selection. Natural Selection only operates to preserve. Without Variation it would have no sphere in which to operate, so that from one point of view Mr. Darwin may be said to attribute the origin of species to Variation rather than Natural Selection. He is, moreover, far from ignoring the influence of other principles, such as Inheritance, Reversion, and Correlation, upon the total result. He may be thought inconsistent with himself in laying stress at times upon the minuteness of the variations which he supposes to have slowly accumulated into specific differences, and at other times admitting the sudden appearance of variations which may be considered as large ones, and which are certainly striking. But in the first instance the great and almost overwhelming difficulty was to induce a belief that forms specifically different could be connected with one another by descent. By showing that a multitude of small differences accumulated would make a large total difference, he made as it were a bridge for the existing incredulity. It now appears that the gulf may be passed with easy strides instead of the little slow steps at first thought necessary. This fortifies the doctrine of the Transmutation of Species, in proportion as there are fewer ‘missing links,’ fewer transitional forms that need to be accounted for.

Of ‘the coexistence of closely similar structures of diverse origin,’ illustrated so forcibly by the instance of the eye, ‘in at least three independent lines of descent, the Mollusca, the Annulosa, and the Vertebrata,’ it can scarcely be denied that Natural Selection alone would be an inadequate explanation. But here again it should be observed that Darwinism does not attribute everything to Natural Selection. It assumes, what must be allowed, that variations occur. In obedience to what laws those variations themselves are produced is an interesting speculation, and a most important subject of inquiry. That such laws or conditions of Variation exist no one can doubt, unless he has been seduced by Ovidian metamorphoses to believe in trees bleeding human blood and human foreheads branching with the antlers of the stag. A knowledge of those conditions might fully explain the coexistence of similar structures of diverse origin, consistently with the principle of Natural Selection. The ignorance of them is scarcely a proof that such coexistence does not harmonize with it.

The objection that giraffes, which profited by long necks in a time of drought, would find them a disadvantage subsequently, as requiring a greatly increased size and strength of muscles to support them, overlooks the law of correlation, by assuming that the elongated neck would be out of proportion to the other conditions of the creature’s fabric.

Mr. Mivart’s fourth objection seems at least an extremely improbable opinion. He refers to Mr. Darwin’s expression, that the goose appears to have a highly inflexible organization, as if he himself thought it possible for a species at length to attain to an organization completely inflexible. Such a view would imply two parents exactly like one another, producing offspring exactly like themselves; and of such exact likenesses no known families afford examples.

The seventh objection recalls the still unexplained physiological difference between ‘species’ and ‘races,’ unions between the former being sterile, and between the latter fertile. In this branch of the subject there is much scope still for inquiry. Some of the difficulty may be due to a trick played us by language. True species have been defined to be those that are not fertile together; and from the definition it follows that races which _are_ fertile together are not true species. But the question is obscured by the use of the two different words ‘races’ and ‘species,’ the real issue being, whether races that are and races that are not fertile together can originate in the same way. The subject in its other bearings has been largely discussed by Mr. Darwin in his work on ‘Animals and Plants under Domestication.’

It remains only to say a few words on the argument from the calculation of chances which is supposed to reduce the survival by natural selection of any particular useful variation almost or altogether to an arithmetical impossibility. ‘The advantage,’ we are told, ‘whatever it may be, is utterly outbalanced by numerical inferiority. A million creatures are born: ten thousand survive to produce offspring. One of the million has twice as good a chance as any other of surviving: but the chances are fifty to one against the gifted individual’s being one of the hundred survivors. No doubt the chances are twice as great against any one other individual, but this does not prevent their being enormously in favour of _some_ average individual[69].’ In this calculation it seems to be overlooked that every individual will vary more or less, and that out of a million variations there is a very great probability that _one_ should give much more than the amount of advantage which the calculation supposes. Nor does it follow that a variation conferring great advantage in the struggle for life should be great in comparison with a creature’s general organization. There is a very probable alternative, that when the advantages are exceedingly slight they may be shared by a great many, and that when falling to the lot of only one or a few, they may be exceedingly important. The doctrines of reversion and inheritance are pressed into the service of the arithmetical argument to show that the acquired advantage would be gradually diminished and finally lost. But Mr. Darwin tells us that, ‘when a new character appears, it is occasionally from the first well-fixed[70].’ The chances upon one principle that a character will not be transmitted are not worth consideration, if, under the operation of some other principle known or unknown, the transmission of the character actually takes place. We are asked whether one white man, introduced into an island otherwise inhabited only by negroes, would be likely to give the whole island eventually a white, or even a yellow, population. Without trying the experiment, we may perhaps safely answer in the negative. But the illustration loses much or all of its point, when we consider how little the circumstances of the experiment would correspond with what ordinarily happens in nature, how little we know whether the white man’s colour would be really an advantage or the reverse, and how complicated are the differences between a white man and a negro. If the blackness of the negro be due to Natural Selection in any considerable degree, we should expect it to suit the conditions which surround him in his native habitation better than a white skin would do. In this case the pallor introduced into the breed by a solitary stranger would gradually disappear in obedience to the principles of Natural Selection, not in opposition to them. To take once more the instance of the giraffe; the useful variation is here by hypothesis an elongated neck; it is conceivable that out of large herds the few survivors of a drought might be exclusively such as possessed this advantage to some extent. These would probably transmit to a large majority of their descendants the tendency to vary in a given direction which they had themselves all more or less exhibited. Their progeny, moreover, would be placed in exceptionally favourable circumstances by the very fact that in the previous drought so many of the same species had been starved to death, who would otherwise have furnished their chief competitors in the struggle for existence. It is still objected that upon this supposition many other animals ought to have acquired giraffe-like necks. But such an expectation is far from being warranted by the principles of Natural Selection. Since all variations are potentially useful, but only those are preserved which suit the surrounding conditions among which they are exhibited, the calculation of chances will itself plead for the probability that a variety of variations will be preserved, rather than the same many times over. Other species competing with the giraffe for food would be little likely to gain an advantage over it by a slight increase in length of neck, though by other variations they might achieve a decided superiority. It is obvious, also, that the advantage assigned to the elongated neck would belong to many other possible variations, such as a lengthened proboscis, far-reaching arms, the climbing powers of the snake or the monkey, the flight of the bird or the insect; all of which may be due to Natural Selection and the subsidiary principles which the theory of Development embraces.

The calling in of subsidiary principles may be thought to spoil the boasted simplicity of the theory. But such an opinion is hypercritical. One might truthfully say of a great patriot that all he did was in obedience to the simple law of duty, without implying that he was exempt from the law of association of ideas, or independent of the mechanical, chemical, and vital laws which regulate many of the functions of all human beings alike.

FOOTNOTES.

[1] These papers were read at various dates between February 1869 and January 1871, before the Torquay Natural History Society.

[2] Read before the Devonshire Association, July 1870.

[3] Horace, Odes, I. xvi. 13:--

Fertur Prometheus addere principi Limo coactus particulam undique Desectam, et insani leonis Vim stomacho apposuisse nostro.

[4] Lyell, ‘Principles of Geology,’ vol. ii. p. 324. Tenth Edition.

[5] Darwin, ‘Animals and Plants under Domestication,’ vol. ii. p. 251.

[6] 1,073,741,824 grains.

[7] ‘On the Origin of Species,’ p. 74. Fourth Edition.

[8] Darwin, ‘Animals and Plants under Domestication,’ vol. ii. p. 379.

[9] 37 dwts. 7 grs., or 895 grs., between seven and eight times the size of the wild fruit. See ‘Animals and Plants under Domestication,’ vol. i. p. 356.

[10] Darwin, ‘Animals and Plants under Domestication,’ passim.

[11] ‘Animals and Plants under Domestication,’ vol. ii. pp. 348-351.

[12] An important caution may here be quoted from Mr. Herbert Spencer. ‘An impression,’ he says, ‘has been given by those who have popularized the sentiments of Embryologists, that, during its development, each higher organism passes through stages in which it resembles the adult forms of lower organisms--that the embryo of a man is at one time like a fish, and at another time like a reptile. This is not the fact. The fact established is, that up to a certain point the embryos of a man and a fish continue similar, and that then differences begin to appear and increase--the one embryo approaching more and more towards the form of a fish; the other diverging from it more and more. And so with the resemblances to the more advanced types.’--_Principles of Biology_, vol. i. p. 143.

[13] ‘Origin of Species,’ p. 270. Mr. Darwin shows how the hexagonal cells of the hive-bee can have arisen from the simple cylindrical form, by bringing the cylinders sufficiently near together, so that their outlines, if completed, would intersect.

The humble-bee makes separate and very irregular rounded cells.

The _melipona domestica_ makes cells that are nearly spherical, but too near together for the spheres to be complete, flat walls of wax being built where they tend to intersect.

A little extra regularity, advantageous for the saving of wax and labour, would produce the symmetrical comb of the hive-bee with its two layers of hexagonal prisms.

[14] See ‘Principles of Biology,’ vol. i. pp. 428-431.

[15] ‘Origin of Species,’ p. 213; ‘Principles of Biology,’ vol. i. pp. 392, 394. The walking-fishes of India and the mud-fishes of Ceylon and New Zealand are described in an interesting article by Dr. Day of Torquay, in ‘All the Year Round’ for June 11th, 1870. Dr. Day seems to think the climbing powers of the _anabas scandens_ less satisfactorily attested than other attributes of these extraordinary groups.

[16] Carpenter, ‘Animal Physiology,’ chap. 14.

[17] The design of this Essay was not, as has been erroneously supposed, to disprove the universality of the Deluge by help of Darwinism, but to remove one great obstacle to the general acceptance of Darwinism by disproving the universality of the Deluge. Taking the Theory of Development for granted, a recent universal Deluge would be too obviously impossible to need arguing against.

[18] Lyell, ‘Principles of Geology,’ ii. 332.

[19] Ibid. ii. 344.

[20] Lyell, ii. 336.

[21] ‘The Malay Archipelago,’ vol. ii. p. 448.

[22] ‘Genesis of the Earth and of Man,’ p. 117; quoted in Sir J. Lubbock’s ‘Prehistoric Times,’ p. 314.

[23] A religious and supremely orthodox poet of the last century enquires, ‘Where is the dust that has not been alive?’--Young, ‘Night Thoughts,’ Night IX, 1. 87.

[24] ‘Mushrooms and Toadstools.’--Worthington G. Smith, p. 17.

[25] ‘Genesis of the Earth and of Man,’ pp. 113, 114.

[26] Genesis, chap. xi.

[27] Sir John Lubbock, ‘Prehistoric Times,’ pp. 338, 346, 452; Herodotus, iv. 26.

[28] See Mill’s ‘History of British India,’ book ii. ch. i. and notes.

[29] ‘Prehistoric Man,’ Dr. Daniel Wilson, p. 101.

[30] ‘The Daughter of Galileo,’ by the author of ‘Mary Powell,’ p. 283.

[31] ‘Origin of Species,’ p. 268.

[32] ‘Good Words for the Young,’ June 1870. Animal Defences. By A. W. Drayson.

[33] Wallace, ‘Essays on Natural Selection,’ p. 227.

[34] ‘The Spectator,’ No. 120.

[35] ‘Spectator,’ No. 121.

[36] Nos. 156, 157.

[37] ‘Spectator,’ No. 519.

[38] ‘Natural History,’ § 985. ‘It is a common experience that dogs know the dog-killer; when, as in times of infection, some petty fellow is sent out to kill the dogs; and that though they have never seen him before, yet they will all come forth, and bark and fly at him.’

[39] See ‘Knight’s Half-Hours with the Best Authors.’ No. 185: from ‘The Fool of Quality.’

[40] ‘Essays on Natural Selection,’ p. 248.

[41] Ibid. p. 128.

[42] This Essay was originally prepared as a sermon for Trinity Sunday. For the text were quoted the well-known words of 2 Peter ii. 16, ‘The dumb ass, speaking with man’s voice, forbad the madness of the prophet.’ The design was to show that some of the most unpopular novelties in scientific opinion bore no necessary antagonism to the deepest mysteries of Christian doctrine. In regard to such an attempt it is perhaps needless to add that the kindliness of the design was not fully appreciated by those for whose benefit it was intended.

[43] As in the inscription ‘Jehu, the son of Omri,’ referred to by Lord A. C. Hervey, in Smith’s Dict. of the Bible, Art. ‘Genealogy.’

[44] Smith’s Dictionary of the Bible, Art. ‘Genealogy of Jesus Christ,’ Lord A. C. Hervey, referring to Dr. Mill. Compare also Hengstenberg, Genuineness of the Pentateuch, vol. ii. p. 294, Translation, 1847.

[45] Sir J. Lubbock, ‘Prehistoric Times,’ p. 502, second edition.

[46] Ibid. p. 223.

[47] Ibid. p. 233.

[48] See chapter on Marriage, in Sir J. Lubbock’s ‘Origin of Civilization.’

[49] Sir J. Lubbock, ‘Prehistoric Times,’ p. 380; Sir C. Lyell, ‘Antiquity of Man,’ p. 27.

[50] Lyell, ‘Elements of Geology,’ p. 118, ed. 1865.

[51] Messrs. Pengelly and Vivian, resident at Torquay, acting members of the distinguished committee of exploration.

[52] See Reports of British Association, 1868, p. 57, and 1869, p. 199, by W. Pengelly, Esq., F.R.S.

[53] This is the popular name for them. They do not petrify the specimens placed in them, but only coat them with stalagmite.

[54] The resuming process has not yet been adopted by the modern Fuegians, for Dr. Hooker informs us that at the extreme south of Tierra del Fuego, and in mid-winter, he has often seen the men lying asleep in their wigwams, without a scrap of clothing, and the women standing naked, and some with children at their breasts, in the water up to their middles gathering limpets and other shell fish, while the snow fell thickly on them and on their equally naked babies.’--Sir J. Lubbock, ‘Prehistoric Times,’ p. 532. Jerome declares that he had himself seen the Attacotti, a British tribe, eating human flesh. See Gibbon (vol. iii. p. 270, ed. 1854), who in several passages refers to the practice among various British tribes of going naked, especially in war, citing Appian, Ammianus, and Giraldus Cambrensis as his authorities for British customs. It will be remembered that Cæsar speaks even of the Southern Britons as fighting ‘omnibus membris expediti.’

[55] ‘Report of British Association, 1869,’ p. 201.

[56] Nov. 21, 1870.

[57] A formation later than the Devonian, and earlier than the New Red Sandstone.

[58] Revelation x. 6, Authorised Version.

[59] See Mr. Pengelly’s paper on the subject in the Transactions of the Devonshire Association for 1868.

[60] ‘Acadian Geology,’ Dawson, p. 386.

[61] See ‘Lecture on Coal,’ by W. Boyd Dawkins, Esq., M.A., F.R.S. Manchester, 1870.

[62] Address to the British Association, 1868, p. 66 of the Report.

[63] In the Collection of W. Pengelly, Esq., F.R.S.

[64] This and the three following letters were originally addressed to the Editor of the _Torquay Directory_, in answer to a gentleman who, in company with large multitudes of his fellow-Britons, both male and female, holds and upon occasion upholds a mass of opinions on Science and Religion, any one of which opinions individually may be right or may be wrong, but which, when held collectively, seem to my humble understanding to be logically incoherent.

[65] Reprinted from ‘Nature,’ No. 30.

[66] Reprinted from ‘Nature,’ No. 56.

[67] Applying to these caterpillars Mr. A Murray’s recent hypothesis for explaining ‘mimicry’ by hybridization, we should draw the poetical inference that a happy marriage is possible between a butterfly and a rose-bush.

[68] ‘Nature,’ No. 66.

[69] ‘Genesis of Species,’ p. 57, quotation (somewhat obscure as it stands) from the North British Review for June, 1867.

[70] ‘Animals and Plants under Domestication,’ vol. ii. p. 63.

INDEX.

Abiogenesis, note on hypothesis of, 126-132.