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 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 24,
1859, and the second edition on January 7, 1860.