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THE ORIGIN OF SPECIES BY MEANS OF NATURAL SELECTION;

or, the PRESERVATION OF FAVOURED RACES IN THE STRUGGLE FOR LIFE.

By Charles Darwin, M.A., F.R.S.,

Author of "The Descent of Man," etc., etc.


Sixth London Edition, with all Additions and Corrections.

The 6th Edition is often considered the definitive edition.

Also see Project Gutenberg Etext #1228 for the First Edition.



"But with regard to the material world, we can at least go so far as
this - we can perceive that events are brought about not by insulated
interpositions of Divine power, exerted in each particular case, but by
the establishment of general laws." - Whewell: "Bridgewater Treatise".

"The only distinct meaning of the word 'natural' is STATED, FIXED or
SETTLED; since what is natural as much requires and presupposes an
intelligent agent to render it so, i.e., to effect it continually or at
stated times, as what is supernatural or miraculous does to effect it
for once." - Butler: "Analogy of Revealed Religion".

"To conclude, therefore, let no man out of a weak conceit of sobriety,
or an ill-applied moderation, think or maintain, that a man can search
too far or be too well studied in the book of God's word, or in the book
of God's works; divinity or philosophy; but rather let men endeavour
an endless progress or proficience in both." - Bacon: "Advancement of
Learning".




AN HISTORICAL SKETCH OF THE PROGRESS OF OPINION ON THE ORIGIN OF
SPECIES,

PREVIOUSLY TO THE PUBLICATION OF THE FIRST EDITION OF THIS WORK.

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 (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 organisation; 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 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.), 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, 1815, in the Introduction to his "Hist. Nat. des
Animaux sans Vertebres". In these works he up holds the doctrine that
all 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 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 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. (I have taken the date of the first publication of Lamarck
from Isidore Geoffroy Saint-Hilaire's ("Hist. Nat. Generale", tom. ii.
page 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. pages 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 afterward; he has pointedly
remarked ("Goethe als Naturforscher", von Dr. Karl Meding, 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.)

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 probleme a reserver entierement a l'avenir, suppose 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 resembles 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 others to bear the diseases of the
country. This race would consequently multiply, while the others would
decrease; not only from their in ability 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
of Dr. Wells' work.

The Hon. and Rev. W. Herbert, afterward Dean of Manchester, in the
fourth volume of the "Horticultural Transactions", 1822, and in his
work on the "Amaryllidaceae" (1837, pages 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
inter-crossing, 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, page 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 Fifty-fifth 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 "Gardeners' Chronicle", on April 7, 1860. The
differences of Mr. Matthew's views from mine are not of much importance:
he seems to consider that the world was nearly depopulated at successive
periods, and then restocked; and he gives as an alternative, that new
forms may be generated "without the presence of any mold 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, page 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 (page 6) as follows: "All species might have been varieties once,
and many varieties are gradually becoming species by assuming constant
and peculiar characters;" but further on (page 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, page 468) has ably given the arguments for and against the
hypothesis of the development and modification of species: he seems to
lean toward the side of change.

The "Vestiges of Creation" appeared in 1844. In the tenth and much
improved edition (1853) the anonymous author says (page 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 coadaptations 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 early 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 M.J. d'Omalius d'Halloy published in an
excellent though short paper ("Bulletins de l'Acad. Roy. Bruxelles",
tom. xiii, page 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", page 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 (page li) of "the
axiom of the continuous operation of creative power, or of the ordained
becoming of living things." Further on (page 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 zoologist 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, page 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," etc.(Ibid., vol. i, page 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. iii. page 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. page
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 Resume appeared in the "Revue et Mag. de Zoolog.", Jan., 1851),
briefly gives his reason for believing that specific characters "sont
fixes, pour chaque espece, tant qu'elle se perpetue au milieu des memes
circonstances: ils se modifient, si les circonstances ambiantes viennent
a changer. En resume, L'OBSERVATION des animaux sauvages demontre deja
la variabilite LIMITEE des especes. Les EXPERIENCES sur les animaux
sauvages devenus domestiques, et sur les animaux domestiques redevenus
sauvages, la demontrent plus clairment encore. Ces memes experiences
prouvent, de plus, que les differences produites peuvent etre de VALEUR
GENERIQUE." In his "Hist. Nat. Generale" (tom. ii, page 430, 1859) he
amplifies analogous conclusions.

From a circular lately issued it appears that Dr. Freke, in 1851
("Dublin Medical Press", page 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", page 102;
since partly republished in the "Nouvelles Archives du Museum", tom. i,
page 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 mysterieuse, indeterminee; fatalite
pour les uns; pour les autres volonte providentielle, dont l'action
incessante sur les etres vivantes determine, a toutes les epoques de
l'existence du monde, la forme, le volume, et la duree de chacun d'eux,
en raison de sa destinee dans l'ordre de choses dont il fait partie.
C'est cette puissance qui harmonise chaque membre a l'ensemble, en
l'appropriant a la fonction qu'il doit remplir dans l'organisme general
de la nature, fonction qui est pour lui sa raison d'etre." (From
references in Bronn's "Untersuchungen uber die Entwickelungs-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'Espece", 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.)

In 1853 a celebrated geologist, Count Keyserling ("Bulletin de la Soc.
Geolog.", 2nd Ser., tom. x, page 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",
etc.), 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
Geograph." Bot. tom. i, page 250), "On voit que nos recherches sur la
fixite ou la variation de l'espece, nous conduisent directement aux
idees emises par deux hommes justement celebres, 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 1, 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, toward whom all zoologists feel so profound a respect,
expressed about the year 1859 (see Prof. Rudolph Wagner,
"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



Online LibraryCharles DarwinOn the origin of species → online text (page 1 of 51)