- The ‘historical sketch’ printed as a preface to the American edition (Origin US ed., pp. i–xi)
- New material added to chapter 4 on ‘Natural selection’ (ibid., pp. 116*–121*)
- The final list of changes added as a Supplement to the volume (ibid., pp. 426–32)
Introduction
Soon after Origin was published, Darwin received a letter from Asa Gray offering to arrange an American reprint of the book and to secure the author a share in possible profits. Darwin responded favourably to Gray’s proposal in his letter of 21 December [1859] (Correspondence vol. 7):
I shd be infinitely obliged if you could aid an American Reprint; & could make, for my sake & Publisher’s, any arrangement for any profit.— The new Edit. is only Reprint; yet I have made a few important corrections. I will have the clean sheets sent over in a few days … I shd be glad for the new Edit to be reprinted, & not the old.—
Darwin was motivated by more than possible profit, for he further added that he thought it ‘of importance that my notions shd be read by intelligent men, accustomed to scientific argument though not naturalists. It may seem absurd but I think such men will drag after them those naturalists, who have too firmly fixed in their heads that a species is an entity.—‘
After Gray had contacted the Boston publishing firm of Ticknor and Fields about this prospect, he discovered that two New York publishers were already well on the way toward publishing the book. Indeed, by early in January D. Appleton & Co. had Origin in type—taken from the first English edition— and were preparing for distribution. Acting on Darwin’s behalf, Gray duly contacted D. Appleton to inquire about author’s copyright and the possibility of reprinting the second English edition, transmitting their response to Darwin (see letters from Asa Gray, [10 January 1860], [17 January 1860], and 23 January 1860).
Although D. Appleton was not obliged by United States law to honour foreign copyright, they agreed to grant Darwin a share of the profits from their sales. However, they demurred about changing the text of their edition since their plates had been fixed through the process of stereotyping (see letter from Asa Gray, 23 January [1860] and n. 2). The firm agreed, however, to consider preparing a new edition at some future date and asked Darwin to provide them with any changes he wanted to make.
Darwin immediately set to work. Although at first sceptical of Baden Powell’s suggestion that he prefix to Origin a list of authors who had maintained the modification of species (two letters to Baden Powell, 18 January 1860), Darwin subsequently changed his mind. On 31 January he told Joseph Dalton Hooker that he was preparing a ‘historical sketch’ for Origin that cited those naturalists who had preceded him in espousing favourable views of the transmutation of species; Darwin sent this off to Gray enclosed in his letter of [8 or 9 February 1860]. He had earlier sent Gray some additions and corrections that he hoped could be included (see letters to Asa Gray, 28 January [1860] and 1 February [1860]).
A month later, in his letter of 8 March [1860], Darwin sent Gray several more substantive corrections to be added to any second American edition. These included a long discussion in response to early criticisms of natural selection (especially that given by Hewett Cottrell Watson in his letter of [3? January 1860]) that Darwin wanted inserted at the conclusion of chapter four. Darwin had informed Charles Lyell about some of the changes he intended to make in the American edition in the letter to Lyell, 18 [and 19 February 1860]. Darwin suggested to Gray that the title page of the new edition should read: “Reprinted from corrected Second Edition with additional corrections” (letter to Asa Gray, 1 February [1860]).
By 1 May 1860, D. Appleton had sold the bulk of the 2250 copies resulting from three separate printings of Origin (see letter to Asa Gray, 22 May [1860] and enclosure) and were preparing to produce the promised ‘revised and augmented’ American edition. Most of the emendations that Darwin had sent were incorporated into the new edition. However, at some point, probably early in May, Darwin had sent a list of further changes for the new American edition that were received too late to be incorporated into the text and were printed in a ‘Supplement’ added to the end of the edition.
This ‘revised and augmented’ American edition of Origin was available in July 1860 (see [Gray] 1860b, p. 116). It is interesting to note that it was in several respects different from the two British editions: it carried the whale–bear case, which had been removed from the second English edition, yet it incorporated many of the other changes Darwin made to the second edition; it also included a number of significant alterations and additions that were only later added, in a somewhat modified form, to the third edition of Origin, published in March 1861 (see Freeman 1977, p. 83). As Gray’s biographer A. Hunter Dupree has noted, ‘Gray’s great accomplishment … was to provide the American public with an edition of the Origin in some respects even ahead of the current English edition.’ (Dupree 1959, p. 271). In fact, this edition was the only one available in the United States until 1873, when D. Appleton prepared a new edition taken from the sixth English edition of 1872 (Freeman 1977, pp. 85–6).
Contributed by the Author to this American Edition.
I will here attempt to give a brief, but I fear imperfect, sketch of the progress of opinion on the Origin of Species. The great majority of naturalists have believed that species were immutable productions and have been separately created: this view has been ably maintained by many authors. A few naturalists, and several who have not particularly studied natural history, believe, on the other hand, that species undergo modification, and that the existing forms of life have descended by true generation from pre-existing forms. Passing over authors of the classical period, and likewise Demaillet and Buffon, with whose writings I am not familiar, Lamarck was the first man, whose view that species undergo change excited much attention. This justly celebrated naturalist published his Philosophie Zoologique in 1809, and his Introduction to Hist. Nat. des animaux sans Vertèbres in 1815, in which works he upholds the doctrine that species are descended from each other. He seems to have been chiefly led to this conclusion by the difficulty of distinguishing species and varieties,—by the almost perfect gradation of the forms in certain groups, and by the analogy of domestic productions. With respect to the means of modification, he attributed something to the action of external conditions, something to the crossing of already existing forms, and much to use and disuse or the effects of habit. To this latter agency he seems to attribute all the beautiful adaptations in nature,—such as the long neck of the giraffe for browsing on the branches of trees.* But he likewise believed in a law of progressive development; and as all the forms of life thus tended to progress, in order to account for the presence of very simple productions at the present day, he maintained that such forms were now spontaneously generated.
Geoffroy Saint Hilaire, as is stated in his Life by his Son, as early as 1795, suspected that what we call species are various degenerations of the same type. It was not until 1828 that he published his conviction that the same forms have not been perpetuated since the origin of all things. Geoffroy seems to have relied chiefly on the conditions of life, or the ‘‘monde ambiant,’’ as the cause of change; but he was cautious, and, as his son says, ‘‘C’est donc un problème à reserver entièrement a l’avenir, suppose même que l’avenir doive avoir prise sur lui.’’
In England, the Hon. and Rev. W. Herbert, afterwards Dean of Manchester, in his work on the Amaryllidaceæ (1837, p. 19, 339), declares that ‘‘horticultural experiments have established, beyond the possibility of refutation, that botanical species are only a higher and more permanent class of varieties.’’ He extends the same view to animals. The Dean believes that single species of each genus were created in an originally highly plastic condition, and that these by intercrossing and by variation have produced all our existing species.
In 1843–44, Prof. Haldeman (in the Boston (U. S.) Journal of Nat. Hist., vol. iv., p. 468) has ably given the arguments for and against the hypothesis of the development and modification of species: he seems to me to lean towards the side of change.
The Vestiges of Creation appeared in 1844. In the last or tenth and much improved edition (1853, p. 155), the anonymous author says: ‘‘The proposition determined on after much consideration is, that the several series of animated beings, from the simplest and oldest up to the highest and most recent, are, under the providence of God, the results, first, of an impulse which has been imparted to the forms of life, advancing them, in definite times, by generation, through grades of organisation terminating in the highest dicotyledons and vertebrata, these grades being few in number, and generally marked by intervals of organic character which we find to be a practical difficulty in ascertaining affinities; second, of another impulse connected with the vital forces, tending in the course of generations to modify organic structures in accordance with external circumstances, as food, the nature of the habitat and the meteoric agencies, these being the ‘adaptations’ of the natural theologian.’’ The author apparently believed that organisation progresses by sudden leaps; but that the effects produced by the conditions of life are gradual. The author argues with much force on general grounds that species are not immutable productions. But, I cannot see how the two supposed ‘‘impulses’’ account in a scientific sense for the numerous and beautiful co-adaptations, which we see throughout nature;—I cannot see that we thus gain any insight how, for instance, a woodpecker has become adapted to its peculiar habits of life. The work, from its powerful and brilliant style, though displaying in the earlier editions little accurate knowledge and a great want of scientific caution, immediately had a very wide circulation. In my opinion, it has done excellent service in calling in this country attention to the subject, and in removing prejudices.
In 1846, the veteran geologist, M. J. d’Omalius d’Halloz, published in an excellent, though short, paper (Bulletins de l’Acad. Roy. Bruxelles, tom. xiii., p. 581), his opinion that it is more probable that new species have been produced by descent with modification, than that they have been separately created: the author first promulgated this opinion in 1831.
M. Isidore Geoffroy Saint Hilaire, in his Lectures delivered in 1850 (of which a Résumé appeared in the Revue et Mag. de Zoolog., Jan. 1851), briefly gives his reasons for believing that specific characters ‘‘sont fixes, pour chaque espèce, tant qu’elle se perpétue au millieu des m–mes circonstances, ils se modifient, si les circonstances ambiantes viennent à changer.’’ ‘‘En résumé, l’observation des animaux sauvages démontre déjà la variabilité limitée des espèces. Les expériences sur les animaux sauvages devenus domestiques, et sur les animaux domestiques redevenus sauvages, la démontrent plus clairement encore. Ces même expériences prouvent, de plus, que les differences produites peuvent être de valeur générique.’’
Mr. Herbert Spencer, in an Essay (originally published in the Leader, March, 1852, and republished in his Essays, 1858), has contrasted the theories of the creation and development of organic beings with remarkable skill and force. He argues from the analogy of domestic productions, from the changes which the embryos of many species undergo, from the difficulty of distinguishing species and varieties, and from the principle of general gradation, that species have been modified; and he attributes the modification to the change of circumstances. The author (1855) has treated Psychology on the principle of the necessary acquirement of each mental power and capacity by gradation.
In 1852 (Revue Horticole, p. 102), M. Naudin, a distinguished botanist,* has expressly stated his belief that species are formed in an analogous manner as varieties are under cultivation; and the latter process he attributes to man’s power of selection. But he does not show how selection can act under nature. He believes, like Dean Herbert, that species when nascent were more plastic. He lays weight on what he calls the principle of finality, ‘‘puissance mystérieuse, indéterminée; fatalité pour les uns; pour les autres, volonté providentielle, dont l’action incessante sur les –tres vivants détermine, à toutes les époques de l’existence du monde, la forme, le volume et la durée de chacun d’eux, en raison de sa destinée dans l’ordre de choses dont il fait partie. C’est cette puissance qui harmonise chaque membre à l’ensomble en l’appropriant à la fonction qu’il doit remplir dans l’organisme général de la nature, fonction qui est pour lui sa raison d’être.’’
In 1853, a celebrated geologist, Count Keyserling (Bulletin de la Soc. Geolog., 2d ser., tom. x., p. 357) suggested that as new diseases, supposed to have been caused by some miasma, have arisen and spread over the world, so at certain periods the germs of existing species may have been chemically affected by circumambient molecules of a particular nature, and thus have given rise to new forms.
The ‘‘Philosophy of Creation’’ has been treated in an admirable manner by the Rev. Baden Powell, in his Essays on the Unity of Worlds, 1855. Nothing can be more striking than the manner in which he shows that the introduction of new species is ‘‘a regular, not a casual, phenomenon,’’ or, as Sir John Herschel expresses it, ‘‘a natural in contradistinction to a miraculous process.’’ I think this work can hardly have failed to have produced a great effect in every philosophical mind.
The third volume of the Journal of the Linnean Society (August, 1858) contains papers by Mr. Wallace and myself, in which, as stated in the introductory remarks to this volume, the theory of Natural Selection is promulgated.
In June, 1859, Professor Huxley gave a lecture before the Royal Institution on the Persistent Types of Animal Life. Referring to such cases, he remarks: ‘‘It is difficult to comprehend the meaning of such facts as these, if we suppose that each species of animal and plant, or each great type of organisation, was formed and placed upon the surface of the globe, at long intervals, by a distinct act of creative power; and it is well to recollect that such an assumption is as unsupported by tradition or revelation as it is opposed to the general analogy of nature. If, on the other hand, we view ‘Persistent Types’ in relation to that hypothesis which supposes the species living at any time to be the result of the gradual modification of pre-existing species,—a hypothesis which, though unproven, and sadly damaged by some of its supporters, is yet the only one to which physiology lends any countenance—their existence would seem to show that the amount of modification which living beings have undergone during geological time is but very small in relation to the whole series of changes which they have suffered.’’
In November, 1859, the first edition of this work was published. In December, 1859, Dr. Hooker published his Introduction to the Tasmanian Flora: in the first part of this admirable essay he admits the truth of the descent and modification of species; and supports this doctrine by many original and valuable observations.
*It is curious how completely my grandfather, Dr. Erasmus Darwin, anticipated these erroneous views in his Zoonomia (vol. i. pp. 500–510), published in 1794.
*M. Lecoq, another French botanist, entertains, I believe, analogous views on the modification and descent of species.
Charles Darwin
Down, Bromley, Kent, Feb. 1860
[Darwin’s response to early criticisms of the operation of natural selection].
A distinguished naturalist has objected that the continued action of natural selection and divergence will tend to make an indefinite number of specific forms. As far as mere inorganic conditions are concerned, it seems probable that a sufficient number of species would soon become adapted to all considerable diversities of heat, moisture, &c.; but I fully admit that the mutual relations of organic beings are the most important, and as the number of species in any country goes on increasing, the organic conditions of life will become more and more complex. Consequently there seems at first to be no limit to the amount of profitable diversification of structure, and therefore no limit to the number of species which might be produced. We do not know that even the most prolific area is fully stocked with specific forms; at the Cape of Good Hope, which supports such an astonishing number of species, many European plants have become naturalised. But geology shows us, at least within the whole immense Tertiary period, that the number of species of shells, and probably of mammals, has not increased. What, then, checks an indefinite increase in the number of species? Firstly, the amount of life (I do not mean the number of specific forms) supported on any area must have a limit, depending so largely as it does on physical conditions: therefore where very many species are supported, each, or nearly each, will be few in individuals; and any species with scanty numbers would be liable to extermination from accidental fluctuations in the nature of seasons and in the number of its enemies. The process of extermination would in such cases be rapid, whereas the process of the production of new species would always be slow. Imagine the extreme case of as many species as individuals in England, and the first severe winter or very dry summer would exterminate thousands on thousands of species; and individuals of other species would take their places. Secondly, I suspect that when any species becomes very rare, close interbreeding will tend to exterminate it; at least authors have thought that this comes into play in accounting for the deterioration of aurochs in Lithuania, of red deer in Scotland, and of bears in Norway, &c. Thirdly, as far as animals are concerned, some species are closely adapted to prey on some one other being; but if this other being had been rare, it would not have been any advantage to the animal to have been produced in close relation to its prey; therefore it would not have been produced by natural selection. Fourthly, when any species becomes few in number, the process of modification will be slower, for the chance of favourable variations arising will be lessened; therefore if we suppose an area to be inhabited by very many species, each, or nearly each, species will be poor in individuals, and consequently the process of modification and of giving birth to new forms will be retarded. Fifthly, and this I am inclined to think is the most important element, a dominant species which has already beaten many competitors in its own home, will tend to spread and supplant many others. Alph. de Candolle has shown that those species which spread widely, tend generally to spread very widely; and consequently they will tend to exterminate several species in several areas, and thus check the inordinate increase of specific forms throughout the world. Hooker has recently shown that in the S. E. corner of Australia, where apparently there are many invaders from different quarters of the world, the endemic Australian species have apparently been greatly reduced in number. How much weight to attribute to these several causes, I do not pretend to assign; but conjointly I think they must limit in each country the tendency to an indefinite augmentation of specific forms.
Natural Selection acts, as we have seen, exclusively by the preservation and accumulation of variations, which are beneficial under the organic and inorganic conditions of life to which each creature is at each successive period exposed. The ultimate result will be that each creature will tend to become more and more improved in relation to its conditions of life. This improvement will, I think, inevitably lead to the gradual advancement of the organisation of the greater number of living beings throughout the world. But here we enter on a very intricate subject, for naturalists have not defined to each other’s satisfaction what is meant by an advance in organisation. Amongst the Vertebrata, the degree of intellect and an approach in structure to man clearly come into play. It might be thought that the amount of change which the various parts and organs undergo in their development from the embryo to maturity would suffice as a standard of comparison; but there are cases, as with certain parasitic crustaceans, in which several parts of the structure become less perfect and even monstrous, so that the mature animal cannot be called higher than its larva. Von Baer’s standard seems the most widely applicable and the best; namely, the amount of differentiation of the different parts (in the adult state, as I should be inclined to add), and their specialisation for different functions; or as Milne Edwards would express it, the completeness of the division of physiological labour. But we shall see how obscure a subject this is, if we look, for instance, to Fish, amongst which some naturalists rank those as highest which, like the sharks, approach nearest to reptiles; whilst other naturalists rank the common bony or teleostean fishes as the highest, inasmuch as they are most strictly fish-like, and differ most from the other vertebrate orders. Still more plainly we see the obscurity of the subject, by turning to plants, where the standard of intellect is of course quite excluded; and here some botanists rank those plants as highest which have every organ, as sepals, petals, stamens and pistils, fully developed in each flower; whereas other botanists, probably with more truth, look at the plants which have their several organs much modified and somewhat reduced in number as being of the highest rank.
If we look at the differentiation and specialisation of the several organs of each being, when adult (and this will include the advancement of the brain for intellectual purposes), as the best standard of highness of organisation, natural selection will clearly lead towards highness; for all physiologists admit that the specialisation of organs, inasmuch as they perform in this state their functions better, is an advantage to each being; and hence the accumulation of variations tending towards specialisation is within the scope of natural selection. On the other hand, we can see, bearing in mind that all organic beings are striving to increase at a high ratio and to seize on every ill-occupied place in the economy of nature, that it is quite possible for natural selection gradually to fit an organic being to a situation in which several organs would be superfluous and useless; and in such cases there might be retrogression in the scale of organisation. Whether organisation on the whole has actually advanced from the remotest geological periods to the present day will be more conveniently discussed in our chapter on geological succession.
But it may be objected, that if all organic beings thus tend to rise in the scale, how is it that throughout the world a multitude of the lowest forms still exist, and how is it that in each great class some forms are far more highly-developed than others? Why have not the more highly-developed forms everywhere supplanted and exterminated the lower? Lamarck, who believed in an innate and inevitable tendency towards perfection in all organic beings, seems to have felt this difficulty so strongly, that he was led to suppose that new and simple forms were continually being produced by spontaneous generation. I need hardly say that science in her progress has forbidden us to believe that living creatures are now ever produced from inorganic matter. On my theory the present existence of lowly organized productions offers no difficulty; for natural selection includes no necessary and universal law of advancement or development; it only takes advantage of such variations as arise and are beneficial to each creature under its complex relations of life. And it may be asked, what advantage, as far as we can see, would it be to an infusorian animalcule—to an intestinal worm—or even to an earth-worm, to be highly organized? If it were no advantage, these forms would be left by natural selection unimproved or but little improved; and might remain for indefinite ages in their present little advanced condition. And geology tells us that some of the lowest forms, as the infusoria and rhizopods, have remained for an enormous period in nearly their present state. But to suppose that most of the many now-existing low forms have not in the least advanced since the first dawn of life, would be rash; for every naturalist who has dissected some of the beings now ranked as very low in the scale, must often have been struck with their really wondrous and beautiful organisation.
Nearly the same remarks are applicable, if we look to the great existing differences in the grades of organisation within almost every class excepting birds; for instance, to the coexistence of mammals and fish in the vertebrata,—or to the coexistence of man and the ornithorhynchus amongst mammalia,—or amongst fish, of the shark and Amphioxus, which latter fish in the extreme simplicity of its structure closely approaches the invertebrate classes. But mammals and fish hardly come into competition with each other; the advancement of certain mammals or of the whole class to the highest grade of organisation would not lead to their taking the place of and thus exterminating fishes. Physiologists believe that the brain must be bathed by warm blood to be highly active, and this requires ærial respiration; so that warm-blooded mammals, when inhabiting the water, live under some disadvantages compared with fishes. In this latter class members of the shark family would not, it is probable, tend to supplant the Amphioxus; the struggle for existence in the case of the Amphioxus must lie with members of the invertebrate classes. The three lowest orders of mammals—namely, marsupials, edentata and rodents—coexist in South America in the same region with numerous monkeys. Although organisation, on the whole, may advance throughout the world, yet the scale of perfection will still present all degrees for the high advancement of certain whole classes, or of certain members of each class, does not at all necessarily lead to the extinction of those groups with which they do not enter into close competition. In some cases, as we shall hereafter see, lowly-organized forms seem to have been preserved to the present day, from having inhabited peculiar or isolated stations where they have been subjected to less severe competition; and where they have not advanced in organization owing to their scanty individual numbers, which, as already explained, retards the chance of favourable variations arising.
Finally, I believe that lowly-organised forms now exist in numbers throughout the world and in nearly every class, from various causes. In some cases favourable variations may never have arisen for natural selection to act on and accumulate. In no case, perhaps, has time sufficed for the utmost possible maximum of development. In some few cases there may have been what we must call retrogression of organisation. But the main cause lies in the circumstance, that under very simple conditions of life, a high organisation would be of no service—possibly would be of actual disservice, as being of a more delicate nature, and more liable to be put out of order and thus injured.
A difficulty, diametrically opposite to this which we have just been considering, might be advanced; namely, looking to the dawn of life, when all organic beings, as we may imagine, presented the simplest structure, how could the first steps in advancement or in the differentiation and specialization of parts arise? I can make no sufficient answer, and can only say that we have no facts to guide us, and therefore that all speculations on this subject would be baseless and useless.
The following additions and alterations, prepared by the authors expressly for this edition, were received too late to be incorporated in their proper places.
Page 46,1 eight lines from bottom, after ‘‘not generally propagated,’’ insert: If it could be shown that monstrosities were even propagated for a succession of generations in a state of nature, modification might be effected (with the aid of natural selection) more abruptly than I am inclined to believe they are.
Page 79,2 six lines from bottom, after word ‘‘nature,’’ insert parenthesis—reading the whole sentence thus: Man can act only on external and visible characters: nature (if I may be allowed for brevity-sake to personify the natural preservation of favoured individuals during the struggle for existence) cares nothing for appearances, except in so far as they may be useful to any being.
Page 168,3 first line, after ‘‘structure of the eye,’’ insert: (though in the fish Amphioxus), the eye is an extremely simple condition without a lens)
Page 168, sixth line from top, omit all seventeen lines beginning with ‘‘In the Articulata,’’ and ending with ‘‘living crustaceans, and bearing in mind,’’ and insert as follows:
[In the great kingdom of the Articulata we can start from an optic nerve, simply coated with pigment, which sometimes forms a sort of pupil, but is destitute of a lens or any other optical mechanism. From this rudimentary eye which can distinguish light from darkness, but nothing else, there is an advance towards perfection along two lines of structure, which Müller thought were fundamentally different; namely, firstly, stemmata, or the so-called ‘‘simple eyes,’’ which have a lens and cornea; and secondly, ‘‘compound eyes,’’ which seem to act mainly or solely by excluding all the rays from each point of the viewed object, except the pencil that comes in a line perpendicular to the convex retina. In the class of compound eyes, besides endless differences in the form, proportion, number and position of the transparent cones coated by the pigment which act by exclusion, we have additions of a more or less perfect concentrating apparatus; thus in the eyes of the meloe the facets of the cornea are ‘‘slightly convex both externally and internally; that is, lens-shaped.’’ In many crustaceans there are two cornea, the external smooth and the internal divided into facets, within the substance of which, as Milne Edward says, ‘‘renflemens lenticulaires paraissent s’etre développés;’’ and sometimes these lenses can be detached in a layer distinct from the cornea. The transparent cones, which were supposed by Müller to act solely by excluding the divergent pencils of light, usually adhere to the cornea, but not rarely they are detached from it, and have their free ends convex, and in this case they must act, I presume, as converging lenses. Altogether, so diversified is the structure of the compound eyes, that Müller makes three main classes, with no less than seven subdivisions of structure. He makes a fourth main class—namely, ‘‘aggregates’’ of stemmata; and he adds that ‘‘this is the transition-form between the mosaic-like compound eyes, unprovided with a concentrating apparatus and organs of vision with such an apparatus.’’
With these facts, here too briefly and imperfectly given, which show how much graduated diversity there is in the eye of our existing articulata, and bearing in mind, &c., &c.
Page 169,4 tenth line from top, after ‘‘transparent tissue,’’ add: with spaces filled with fluid and with a nerve sensitive, &c., &c.
Page 169, sixteenth line from top, after ‘‘there is a power,’’ insert in brackets: [natural selection]
Page 170,5 twenty-first line from top, after ‘‘insensible steps,’’ insert: Certain plants, as some Leguminosæ , Violaceæ , &c., bear two kinds of flowers; one having the normal structure of the order, the other kind being degraded, though sometimes more fertile than the perfect flowers; if the plant ceased to bear its perfect flowers, and this did occur during several years with an imported specimen of Aspicarpa in France, a great and sudden transition would in fact be effected in the nature of the plant.
Pages 293 and 294.6 Omit thirty lines, beginning, ‘‘On the state of Development,\rm ‘‘ and ending with ‘‘class, may have beaten the highest molluscs,’’ and insert as follows:
On the state of Development of ancient compared with living Forms.— We have seen in the Fourth Chapter that the degree of differentiation and specialisation of the parts of all organic beings, when come to maturity, is the best standard as yet suggested of their degree of perfection or highness. We have also seen that, as the specialisation of parts or organs is an advantage to each being, so natural selection will constantly tend thus to render the organisation of each more specialised and perfect, and in this sense higher; not but that it may, and will, leave many creatures fitted for simple conditions of life with simple and unimproved structures. In another and more general manner we can see that, on the theory of natural selection, the more recent forms will tend to be higher than their progenitors; for each new species is formed by having had some advantage in the struggle for life over other and preceding forms. If, under a nearly similar climate, the eocene inhabitants of one quarter of the world were put into competition with the existing inhabitants of the same or some other quarter, the eocene fauna or flora would certainly be beaten and exterminated; as would a secondary fauna by an eocene, and a palæ ozoic fauna by a secondary fauna. So that by this fundamental test of victory in the battle for life, as well as by the standard of the specialisation of organs, modern forms ought, on the theory of natural selection, to stand higher than ancient forms. Is this the case? A large majority of palaeontologists would certainly answer in the affirmative; but in my imperfect judgment, I can, after having read the discussions on this subject by Lyell and by Hooker in regard to plants, concur only to a certain7 limited extent. Nevertheless, it may be anticipated that the evidence will be rendered more decisive by future geological research.
The problem is in many ways excessively intricate. The geological record, at all times imperfect, does not extend far enough back, as I believe, to show with unmistakable clearness that within the known history of the world organisation has largely advanced. Even at the present day, looking to members of the same class, naturalists are not unanimous which forms are highest; thus some look at the Selaceans or sharks from their approach in some important point of structure to reptiles as the highest fish; others look at the teleosteans as the highest. The ganoids stand intermediate between the selaceans and teleosteans; the latter, at the present day, are largely preponderant in number, but formerly selaceans and ganoids alone existed; and in this case, according to the standard of highness chosen, so will it be said that fishes have advanced or have retrograded in organisation. To attempt to compare in the scale of highness members of distinct types seems hopeless; who will decide whether cuttle-fish be higher than a bee? that insect which the great Von Baer believed to be ‘‘in fact more highly organised than a fish, although upon another type.’’ In the complex struggle for life it is quite credible that crustaceans, for instance, not very high in their own class, might beat the cephalopods or highest molluscs; and such crustaceans, though not highly developed, would stand very high in the scale of invertebrate animals, if judged by the most decisive of all trials,—the law of battle.
Besides this inherent difficulty in deciding which forms are the most advanced in organization, we ought not solely to compare the highest members of a class at any two distant periods,—though undoubtedly this is one and perhaps the most important element in striking a balance—but we ought to compare all the members, high and low, at the two periods. At an ancient epoch the highest and lowest molluscs—namely, cephalopods and brachiopods—swarmed in numbers; at the present time, both these orders have been greatly reduced, whereas other orders, intermediate in grade of organisation, have largely increased; consequently some naturalists have maintained that molluscs were formerly more highly developed than at present; but a stronger case can be made out on the other side by considering the vast reduction at the present day of the lowest molluscs; more especially as the existing cephalopods, though so few in number, are more highly organised than their ancient representatives. We ought, also, to consider the relative proportional numbers of the high and low classes in the population of the world at the two periods; if, for instance, at the present day there were fifty thousand kinds of vertebrate animals, and if we had reason to believe that at some former period there were only ten thousand kinds, we ought to look at this increase in number of the highest class, which implies a great displacement of lower forms, as a decided advance in the organisation of the world, whether or not it were the higher vertebrata which had thus largely increased. We can thus see how hopelessly difficult it will apparently forever be to compare with perfect fairness under such extremely complex relations the standard of organisation of the imperfectly known faunas of successive periods of the earth’s history.
We shall appreciate (under one important point of view) this difficulty the more clearly, by looking to the case of certain existing faunas and floras. From the extraordinary manner in which European productions have recently spread over New Zealand, &c., &c.
Page 417,8 25th line, after ‘‘facts above specified,’’ insert:
It is no valid objection that science as yet throws no light on the origin of Life. Who can explain what is the essence of the Attraction of gravity? Although Leibnitz accused Newton of introducing ‘‘occult qualities and miracles into philosophy;’’ yet this unknown element of attraction is now universally looked at as a vera causa perfectly well established.]
[I see no good reason why the views given in this volume should shock the religious feelings of any one. It is satisfactory, as showing how transient such impressions are, to remember that the greatest discovery ever made by man, namely, the law of gravity, was attacked by Leibnitz, ‘‘as subversive of natural and inferentially of revealed religion.’’ A celebrated author and divine, &c., &c.
Page 420,9 fifteen lines from top, after ‘‘deceitful guide,’’ omit whole remainder of paragraph, and insert, instead, as follows:
Nevertheless, all living things have much in common; in their chemical composition, their cellular structure, their laws of growth, and their liability to injurious influences. We see this in so trifling a circumstance as that the same poison often similarly affects plants and animals, or that the poison secreted by the gall-fly produces monstrous growths on the wild rose or oak tree. In all organic beings the union of a male and female elemental cell seems occasionally to be necessary for the production of a new being. In all, as far as is at present known, the germinal vesicle is the same. So that every individual organic being starts from a common origin. If we look even to the two main divisions—namely, to the animal and vegetable kingdoms—certain low forms are so far intermediate in character that naturalists have disputed to which kingdom they should be referred; and on the principle of natural selection with divergence of character, it does not seem utterly incredible that from some such intermediate production both animals and plants might possibly have been developed. Therefore I should infer that probably all the organic beings which have ever lived on this earth have descended from some one primordial form, into which life was first breathed by the Creator. But this inference is chiefly grounded on analogy, and it is immaterial whether or not it be accepted. The case is different with the members of each great class, as the Vertebrata or Articulata; for here, as has just been remarked, we have in the laws of homology and embryology, &c., some distinct evidence that all have descended from a single primordial parent.]
Notes:
1 The pagination of the American edition of Origin does not correspond to that of the English edition. See the first edition of Origin, p. 44.
2 Origin, p. 83.
3 Origin, pp. 187–8. This phrase and the following, longer discussion of the modification of the eye were added to the third edition of Origin (Origin 3d ed., pp. 363–6). See also letter from John Lubbock, [after 28 April 1860?].
4 Origin, p. 188.
5 Origin, p. 190.
6 Origin, pp. 336–7. This material was added to Origin 3d ed., pp. 363–6.
7 The word is misspelled ‘cretain’ in the original text.
8 The change was made to the text of the second edition of Origin (Origin 2d ed., p. 481). It was included in a slightly modified form in Origin 3d ed., pp. 514–15.
9 Origin 2d ed., p. 484. The material was included in Origin 3d ed., pp. 518–19.
