The Origin of Species
Preface to the Third Edition
by Charles Darwin
I will here give a brief sketch of the progress of opinion on the Origin of Species.
Until recently the great majority of naturalists believed that species were immutable
productions, and had been separately created. This view has been ably maintained by many
authors. Some few naturalists, on the other hand, have believed that species undergo
modification, and that the existing forms of life are the descendants by true generation
of pre-existing forms. Passing over allusions to the subject in the classical writers,(1)
the first author who in modern times has treated it in a scientific spirit was Buffon. But
as his opinions fluctuated greatly at different periods, and as he does not enter on the
causes or means of the transformation of species, I need not here enter on details.
Lamarck was the first man whose conclusions on the subject excited much attention. This
justly-celebrated naturalist first published his views in 1801; he much enlarged them in
1809 in his "Philosophie Zoologique,' and subsequently, in 1815, in the Introduction
to his "Hist. Nat. des Animaux sans Vertébres.' In these works he upholds the
doctrine that species, including man, are descended from other species. He first did the
eminent service of arousing attention to the probability of all change in the organic, as
well as in the inorganic world, being the result of law, and not of miraculous
interposition. Lamarck seems to have been chiefly led to his conclusion on the gradual
change of species, by the difficulty of distinguishing species and varieties, by the
almost perfect gradation of forms in certain groups, and by the analogy of domestic
productions. With respect to the means of modification, he attributed something to the
direct action of the physical conditions of life, something to the crossing of already
existing forms, and much to use and disuse, that is, to the effects of habit. To this
latter agency he seemed 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 tend to
progress, in order to account for the existence at the present day of simple productions,
he maintains that such forms are now spontaneously generated.(2)
Geoffroy Saint-Hilaire, as is stated in his 'Life,' written by his son, suspected, as
early as 1795, 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. He was cautious
in drawing conclusions, and did not believe that existing species are now undergoing
modification; and, as his son adds, "C'est donc un problème à réserver
entièrement à l'avenir, supposé meme que l'avenir doive avoir prise sur lui.'
In 1813, Dr W. C. Wells read before the Royal Society 'An Account of a White female,
part of whose skin resembled that of a Negro'; but his paper was not published until his
famous 'Two Essays upon Dew and Single Vision' appeared in 1818. In this paper he
distinctly recognises the principle of natural selection, and this is the first
recognition which has been indicated; but he applies it only to the races of man, and to
certain characters alone. After remarking that negroes and mulattoes enjoy an immunity
from certain tropical diseases, he observes, firstly, that all animals tend to vary in
some degree, and, secondly, that agriculturists improve their domesticated animals by
selection; and then, he adds, but what is done in this latter case 'by art, seems to be
done with equal efficacy, though more slowly, by nature, in the formation of varieties of
mankind, fitted for the country which they inhabit. Of the accidental varieties of man,
which would occur among the first few and scattered inhabitants of the middle regions of
Africa, some one would be better fitted than the others to bear the diseases of the
country. This race would consequently multiply, while the others would decrease; not only
from their inability to sustain the attacks of disease, but from their incapacity of
contending with their more vigorous neighbours. The colour of this vigorous race I take
for granted, from what has been already said, would be dark. But the same disposition to
form varieties still existing, a darker and a darker race would in the course of time
occur: and as the darkest would be the best fitted for the climate, this would at length
become the most prevalent; if not the only race, in the particular country in which it had
originated.' He then extends these same views to the white inhabitants of colder climates.
I am indebted to Mr Rowley, of the United States, for having called my attention, through
Mr Brace, to the above passage in Dr Wells' work.
The Hon. and Rev. W. Herbert, afterwards Dean of Manchester, in the fourth volume of
the 'Horticultural Transactions,' 1822, and in his work on the 'Amaryllidaceae' (1837, pp.
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 have produced, chiefly by intercrossing, but likewise by variation, all our existing
species.
In 1826 Professor Grant, in the concluding paragraph in his well-known paper
('Edinburgh philosophical journal,' vol. xiv. p. 283) on the Spongilla, clearly declares
his belief that species are descended from other species, and that they become improved in
the course of modification. This same view was given in his 55th Lecture, published in the
'Lancet' in 1834.
In 1831 Mr Patrick Matthew published his work on 'Naval Timber and Arboriculture,' in
which he gives precisely the same view on the origin of species as that (presently to be
alluded to) propounded by Mr Wallace and myself in the 'Linnean journal,' and as that
enlarged in the present volume. Unfortunately the view was given by Mr Matthew very
briefly in scattered passages in an Appendix to a work on a different subject, so that it
remained unnoticed until Mr Matthew himself drew attention to it in the 'Gardener's
Chronicle,' on April 7th, 1860. The differences of Mr Matthew's view from mine are not of
much importance; he seems to consider that the world was nearly depopulated at successive
periods, and then re-stocked; and he gives as an alternative, that new forms may be
generated ' without the presence of any mould or germ of former aggregates.' I am not sure
that I understand some passages; but it seems that he attributes much influence to the
direct action of the conditions of life. He clearly saw, however, the full force of the
principle of natural selection.
The celebrated geologist and naturalist, Von Buch, in his excellent 'Description
physique des Isles Canaries' (1836, p. 147), clearly expresses his belief that varieties
slowly become changed into permanent species, which are no longer capable of
intercrossing.
Rafinesque, in his 'New Flora of North America,' published in 1836, wrote (p. 6) as
follows:- 'All species might have been varieties once, and many varieties are gradually
becoming species by assuming constant and peculiar characters'; but farther on (p. 18) he
adds, 'except the original types or ancestors of the genus.'
In 1843-44 Professor Haldeman ('Boston journal of Nat. Hist. U. States, vol. iv. p.
468) has ably given the arguments for and against the hypothesis of the development and
modification of species: he seems to lean towards the side of change.
The 'Vestiges of Creation' appeared in 1844. In the tenth and much improved edition
(1853) the anonymous author says (p. 155):- '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 believes that
organisation progresses by sudden leaps, but that the effects produced by the conditions
of life are gradual. He 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 this country in calling attention to the subject, in removing
prejudice, and in thus preparing the ground for the reception of analogous views.
In 1846 the veteran geologist N. J. d'Omalius d'Halloy 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.
Professor Owen, in 1849 ('Nature of Limbs,' p. 86), wrote as follows:- "The
archetypal idea was manifested in the flesh under diverse such modifications, upon this
planet, long prior to the existence of those animal species that actually exemplify it. To
what natural laws or secondary causes the orderly succession and progression of such
organic phenomena may have been committed, we, as yet, are ignorant.' In his Address to
the British Association, in 1858, he speaks (p. li.) of "the axiom of the continuous
operation of creative power, or of the ordained becoming of living things.' Farther on (p.
xc.), after referring to geographical distribution, he adds, 'These phenomena shake our
confidence in the conclusion that the Apteryx of New Zealand and the Red Grouse of England
were distinct creations in and for those islands respectively. Always, also, it may be
well to bear in mind that by the word ''creation'' the zoologist means '"a process he
knows not what.'' He amplifies this idea by adding that when such cases as that of the Red
Grouse are enumerated by the zoologists as evidence of distinct creation of the bird in
and for such islands, he chiefly expresses that he knows not how the Red Grouse came to be
there, and there exclusively; signifying also, by this mode of expressing such ignorance,
his belief that both the bird and the islands owed their origin to a great first Creative
Cause.' If we interpret these sentences given in the same Address, one by the other, it
appears that this eminent philosopher felt in 1858 his confidence shaken that the Apteryx
and the Red Grouse first appeared in their respective homes, 'he knew not how,' or by some
process 'he knew not what.'
This Address was delivered after the papers by Mr Wallace and myself on the Origin of
Species, presently to be referred to, had been read before the Linnean Society. When the
first edition of this work was published, I was so completely deceived, as were many
others, by such expressions as 'the continuous operation of creative power,' that I
included Professor Owen with other palaeontologists as being firmly convinced of the
immutability of species; but it appears ('Anat. of Vertebrates,' vol. iii. p. 796) that
this was on my part a preposterous error. In the last edition of this work I inferred, and
the inference still seems to me perfectly just, from a passage beginning with the words
'no doubt the type-form,' &c. (Ibid. vol. i. p. xxxv.), that Professor Owen admitted
that natural selection may have done something in the formation of a new species; but this
it appears (Ibid. vol. nl. p. 798) is inaccurate and without evidence. I also gave some
extracts from a correspondence between Professor Owen and the Editor of the 'London
Review,' from which it appeared manifest to the Editor as well as to myself, that
Professor Owen claimed to have promulgated the theory of natural selection before I had
done so; and I expressed my surprise and satisfaction at this announcement; but as far as
it is possible to understand certain recently published passages (Ibid. vol. iii. p. 798)
I have either partially or wholly again fallen into error. It is consolatory to me that
others find Professor Owen's controversial writings as difficult to understand and to
reconcile with each other, as I do. As far as the mere enunciation of the principle of
natural selection is concerned, it is quite immaterial whether or not Professor Owen
preceded me, for both of us, as shown in this historical sketch, were long ago preceded by
Dr Wells and Mr Matthews.
M. Isidore Geoffroy Saint-Hilaire, in his lectures delivered in 1850 (of which a
Résumé appeared in the 'Revue et Nag. de Zoolog.,' Jan. 1851), briefly gives his reason
for believing that specific characters "sont fixés, pour chaque espèce, tant
qu'elle se perpétue au milieu des mèmes circonstances: ils se modifient, si les
circonstances ambiantes viennent à changer.' 'En résumé, l'observation des
animaux sauvages démontre déjà la variabilité limité des espèces. Les expériences
sur les animaux sauvages devenus domestiques, et sur les animaux domestiques redevenus
sauvages, la démontrent plus clairement encore. Ces memes expériences prouvent, de plus,
que les différences produites peuvent etre de valeur générique.' In his 'Hist.
Nat. Généralé (tom. ii. p. 430, 1859) he amplifies analogous conclusions.
From a circular lately issued it appears that Dr Freke, in 1851 ("Dublin Medical
Press,' p. 322), propounded the doctrine that all organic beings have descended from one
primordial form. His grounds of belief and treatment of the subject are wholly different
from mine; but as Dr Freke has now (1861) published his Essay on the 'Origin of Species by
means of Organic Affinity,' the difficult attempt to give any idea of his views would be
superfluous on my part.
Mr Herbert Spencer, in an Essay (originally published in the 'Leader,' March, 1852, and
republished in his 'Essays,' in 1858), has contrasted the theories of the Creation and the
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 also treated psychology on the principle of
the necessary acquirement of each mental power and capacity by gradation.
In 1852 M. Naudin, a distinguished botanist, expressly stated, in an admirable paper on
the Origin of Species ('Revue Horticole, p. 102; since partly republished in the
'Nouvelles Archives du Muséum,' tom. i. p. 171), 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 acts under nature. He
believes, like Dean Herbert, that species, when nascent, were more plastic than at
present. 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 ètres 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'ensemble, 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'ètre.'(3)
In 1853 a celebrated geologist, Count Keyserling ("Bulletin de la Soc. Gèolog.,'
2nd 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.
In this same year, 1853, Dr Schaaffhausen published an excellent pamphlet ('Verhand.
des Naturhist. Vereins der preuss. Rheinlands,' &c.), in which he maintains the
development of organic forms on the earth. He infers that many species have kept true for
long periods, whereas a few have become modified. The distinction of species he explains
by the destruction of intermediate graduated forms. 'Thus living plants and animals are
not separated from the extinct by new creations, but are to be regarded as their
descendants through continued reproduction.'
A well-known French botanist, M. Lecoq, writes in 1854 ('Etudes sur Géograph. Bot.,'
tom. i. p. 250), 'On voit que nos recherches sur la fixité ou la variation de l'espèce,
nous conduisent directement aux idées émises, par deux hommes justement célèbres,
Geoffroy Saint-Hilaire et Goethe.' Some other passages scattered through M. Lecoq's large
work, make it a little doubtful how far he extends his views on the modification of
species.
The 'Philosophy of Creation' has been treated in a masterly 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.'
The third volume of the "Journal of the Linnean Society' contains papers, read
July 1st, 1858, by Mr Wallace and myself, in which, as stated in the introductory remarks
to this volume, the theory of Natural Selection is promulgated by Mr Wallace with
admirable force and clearness.
Von Baer, towards whom all zoologists feel so profound a respect, expressed about the
year 1859 (see Prof. Rudolph Wagner, a "Zoologisch-Anthropologische Untersuchungen,'
1861, s. 51) his conviction, chiefly grounded on the laws of geographical distribution,
that forms now perfectly distinct have descended from a single parent-form.
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 December, 1859, Dr Hooker published his 'Introduction to the Australian Flora.' In
the first part of this great work he admits the truth of the descent and modification of
species, and supports this doctrine by many original observations.
The first edition of this work was published on November 24th, 1859, and the second
edition on January 7th, 1860.
Footnotes
(1) Aristotle, in his 'Physicae Auscultationes' (lib. 2,
cap. 8, s. 2), after remarking that rain does not fall in order to make the corn grow, any
more than it falls to spoil the farmer's corn when threshed out of doors, applies the same
argument to organization: and adds (as translated by Mr Clair Grece, who first pointed out
the passage to me), 'So what hinders the different parts [of the body] from having this
merely accidental relation in nature? as the teeth, for example, grow by necessity, the
front ones sharp, adapted for dividing, and the grinders flat, and serviceable for
masticating the food; since they were not made for the sake of this, but it was the result
of accident. And in like manner as to the other parts in which there appears to exist an
adaptation to an end. Wheresoever, therefore, all things together (that is all the parts
of one whole) happened like as if they were made for the sake of something, these were
preserved, having been appropriately constituted by an internal spontaneity, and
whatsoever things were not thus constituted, perished, and still perish. We here see the
principle of natural selection shadowed forth, but how little Aristotle fully comprehended
the principle, is shown by his remarks on the formation of the teeth.
(2) I have taken the date of the first publication of
Lamarck from Isid. Geoffroy Saint-Hilaire's ('Hist. Nat. Générale,' tom. ii. p. 405,
1859) excellent history of opinion on this subject. In this work a full account is given
of Buffon's conclusions on the same subject. It is curious how largely my grandfather, Dr
Erasmus Darwin, anticipated the views and erroneous grounds of opinion of Lamarck in his
'Zoonomia' (vol. i. pp. 500-510), published in 1794. According to Isid. Geoffroy there is
no doubt that Goethe was an extreme partisan of similar views, as shown in the
Introduction to a work written in 1794 and 1795, but not published till long afterwards:
he has pointedly remarked ('Goethe als Naturforscher,' von Dr Karl Medinge s. 34) that the
future question for naturalists will be how, for instance, cattle got their horns, and not
for what they are used. It is rather a singular instance of the manner in which similar
views arise at about the same time, that Goethe in Germany, Dr Darwin in England, and
Geoffroy Saint-Hilaire (as we shall immediately see) in France; came to the same
conclusion on the origin of species, in the years 1794-5.
(3) From references in Bronn's 'Untersuchungen über die
Entwickenlungs-Gesetze,' it appears that the celebrated botanist and palaeontologist Unger
published, in 1852, his belief that species undergo development and modification. Dalton,
likewise, in Pander and Dalton's work on Fossil Sloths, expressed, in 1821 a similar
belief. Similar views have, as is well known, been maintained by Oken in his mystical
'Natur-philosophie.' From other references in Godron's work 'Sur l'Espéce,' it seems that
Bory St Vincent, Burdach, Poiret, and Fries, have all admitted that new species are
continually being produced.
I may add, that of the thirty-four authors named in this Historical
Sketch, who believe in the modification of species, or at least disbelieve in separate
acts of creation, twenty-seven have written on special branches of natural history or
geology.