EARLY ATTEMPTS TO ESTABLISH THE DOCTRINE OF EVOLUTION FOR THE ORGANIC
WORLD
In studying the history of Evolutionary ideas, it is necessary to keep
in mind that there are two perfectly distinct lines of thought, the
origin and development of which have to be considered.
_First._ The conviction that species are not immutable, but that, by
some means or other, new forms of life are derived from pre-existing
ones.
_Secondly._ The conception of some process or processes, by which this
change of old forms into new ones may be explained.
Buffon, Kant, Goethe, and many other philosophic thinkers, have been
more or less firmly persuaded of the truth of the first of these
propositions; and even Linnaeus himself was ready to make admissions in
this direction. It was impossible for anyone who was convinced of the
truth of the doctrine of continuity or evolution in the _inorganic_
world, to avoid the speculation that the same arguments by which the
truth of that doctrine was maintained must apply also to the _organic_
world.
Hence we find that directly the _Principles of Geology_ was published,
thinkers, like Sedgwick and Whewell, at once taxed Lyell with holding
that 'the creation of new species is going on at the present day,' and
Lyell replied to the latter:--
'It was impossible, I think, for anyone to read my work and not
to perceive that my notion of uniformity in the existing causes
of change always implied that they must for ever produce an
endless variety of effects, _both in the animate and inanimate
world_[80].'
And to Sedgwick, Lyell wrote:--
'Now touching my opinion,' concerning the creation of new
species at the present day, 'I have no right to object, _as I
really entertain it_, to your controverting it; at the same time
you will see, on reading my chapter on the subject, that I have
studiously avoided laying down the doctrine dogmatically as
capable of proof. I have admitted that we have only data for
_extinction_, and I have left it to be inferred, instead of
enunciating it even as my opinion, that the place of lost
species is filled up (as it was of old) from time to time by new
species. I have only ventured to say that had new mammalia come
in, we could hardly have hoped to verify the fact[81].'
That Lyell was convinced of the truth of the doctrine of the evolution
of species is shown by his correspondence with friends and sympathisers
like Scrope and John Herschel. But he wrote:
'If I had stated ... the possibility of the introduction or
origination of fresh species being a natural, in
contradistinction to a miraculous process, I should have raised
a host of prejudices against me, which are unfortunately opposed
at every step to any philosopher who attempts to address the
public on these mysterious subjects[82].'
That Lyell was justified in not increasing the difficulties which would
retard the reception of his views, by introducing matter, which he still
regarded as of a more or less speculative character, I think everyone
will be prepared to admit. Darwin had to contend with the same
difficulty in writing the _Origin of Species_. To have included the
question of the origin of mankind _prominently_ in that work would have
raised an almost insurmountable barrier to its reception. He says in his
autobiography, 'I thought it best, in order that no honourable man
should accuse me of concealing my views, to add that by the work "light
would be thrown on the origin of man and his history." It would have
been useless and injurious to the success of the book to have paraded,
without giving evidence, my conviction with respect to his origin[83].'
Huxley and Haeckel have both borne testimony to the fact that Lyell, at
the time he wrote the _Principles_, was firmly convinced that new
species had originated by evolution from old ones. Indeed in a letter to
John Herschel in 1836 he goes very far in the direction of anticipating
the lines in which enquiries on the _method_ of evolution must proceed,
having even a prevision of the doctrine of _mimicry_, long afterwards
established by Bates and others. Lyell wrote:--
'In regard to the origination of new species, I am very glad to
find that you think it probable that it may be carried on
through the intervention of intermediate causes. I left this
rather to be inferred, not thinking it worth while to offend a
certain class of persons by embodying in words what would only
be a speculation.... One can in imagination summon before us a
small part at least of the circumstances that must be
contemplated and foreknown, before it can be decided what powers
and qualities a new species must have in order to enable it to
endure for a given time, and to play its part in due relation to
all other beings destined to coexist with it, before it dies
out.... It may be seen that unless some slight additional
precaution be taken, the species about to be born would at a
certain era be reduced to too low a number. There may be a
thousand modes of ensuring its duration beyond that time; one,
for example, may be the rendering it more prolific, but this
would perhaps make it press too hard upon other species at other
times. Now if it be an insect it may be made in one of its
transformations to resemble a dead stick, or a leaf, or a
lichen, or a stone, so as to be somewhat less easily found by
its enemies; or if this would make it too strong, an occasional
variety of the species may have this advantage conferred on it;
or if this would be still too much, one sex of a certain
variety. Probably there is scarcely a dash of colour on the wing
or body of which the choice would be quite arbitrary, or which
might not affect its duration for thousands of years. I have
been told that the leaf-like expansions of the abdomen and
thighs of a certain Brazilian Mantis turn from green to yellow
as autumn advances, together with the leaves of plants among
which it seeks its prey. Now if species come in succession, such
contrivances must sometimes be made, and such relations
predetermined between species, as the Mantis, for example, and
plants not then existing, but which it was foreseen would exist
together with some particular climate at a given time. But I
cannot do justice to this train of speculation in a letter, and
will only say that it seems to me to offer a more beautiful
subject for reasoning and reflecting on, than the notion of
great batches of new species all coming in and afterwards going
out at once[84].'
We have cited this very remarkable passage, as it affords striking
evidence of how deeply Lyell had thought on this great question at a
very early period. Nevertheless it is certain that when he wrote the
second volume of the _Principles_, he had not been able to satisfy
himself that any hypothesis of the _mode_ of evolution, that had up to
that time been suggested, could be regarded as satisfactory.
The only serious attempt to _explain_ the derivation of new species from
old ones that came before Lyell was that of the illustrious Lamarck.
Very noteworthy was the work of that old wounded French soldier,
afflicted in his later years as he was by blindness. By his early
labours, Lamarck had attained a considerable reputation as a botanist,
and later in life he turned his attention to zoology, and then to
palaeontology and geology. In zoology, he did for the study of
invertebrate animals what his great contemporary Cuvier was
accomplishing for the vertebrates; but, with regard to the origin of
species, he arrived at conclusions directly at variance with those of
his distinguished rival.
We are indebted to Professor Osborn[85] for calling attention to that
remarkable, but little known work of Lamarck's--_Hydrogeologie_--published
in 1802, seven years before his _Philosophie Zoologique_ appeared. This
work is especially interesting as showing to how great an extent--as in
the case of Darwin, Wallace and others--it was geological phenomena which
played an important part in leading Lamarck to evolutionary convictions.
"In Geology," Professor Osborn writes,
'Lamarck was an ardent advocate of uniformity, as against the
Cataclysmal School. The main principles are laid down in his
_Hydrogeologie_, that all the revolutions of the earth are
extremely slow. "For Nature," he says, "time is nothing. It is
never a difficulty, she always has it at her disposal; and it is
for her the means by which she has accomplished the greatest as
well as the least results[86]."'
On the subject of subaerial denudation (the action of rain and rivers in
wearing down the earth's surface), Lamarck's views were as clear and
definite as those of Hutton himself; though it is almost certain that he
could never have seen, or even heard of, the writings of the great
Scottish philosopher. On some other questions of geological dynamics,
however, it must be confessed that Lamarck's views and speculations were
rather crude and unsatisfactory.
In his _Philosophie Zoologique_, published in the same year that Charles
Darwin was born (1809), Lamarck brought forward a great body of evidence
in favour of evolution, derived from his extensive knowledge of botany,
zoology and geology. He showed how complete was the gradation between
many forms ranked as species, and how difficult it was to say what forms
should be classed as 'varieties' and what as 'species.'
But when he came to indicate a possible method by which one species
might be derived from another, he was less happy in his suggestions. He
recognised the value of the evidence derived from the study of the races
which have arisen among domestic animals, and from the crossing of
different forms. But his main argument was derived from the acknowledged
fact that use or disuse may cause the development or the partial atrophy
of organs--the case of the 'blacksmith's arm.' Unfortunately some of the
suggestions made by Lamarck, in this connexion--like that of the
elongation of the giraffe's neck to enable it to browse on high
trees--were of a kind that made them very susceptible to ridicule. His
theory was of course dependent on the admission that acquired characters
were transmitted from parents to children, and in the absence of any
suggestion of 'selection,' it did not appeal strongly to thinkers on
this question.
Lyell first became acquainted with the writings of Lamarck in 1827. As
he was returning from the Oxford circuit for the last time--having now
resolved to give up law and devote himself to geological work
exclusively--he wrote to his friend Mantell as follows:--
'I devoured Lamarck _en voyage_.... His theories delighted me
more than any novel I ever read, and much in the same way, for
they address themselves to the imagination, at least of
geologists who know the mighty inferences which would be
deducible were they established by observations. But though I
admire even his flights, and feel none of the _odium
theologicum_ which some modern writers in this country have
visited him with, I confess I read him rather as I hear an
advocate on the wrong side, to know what can be made of the case
in good hands. I am glad he has been courageous enough and
logical enough to admit that his argument, if pushed as far as
it must go, if worth anything, would prove that men may have
come from the Ourang-Outang. But after all, what changes species
may really undergo! How impossible will it be to distinguish and
lay down a line, beyond which some of the so-called extinct
species have never passed into recent ones. That the earth is
quite as old as he supposes, has long been my creed, and I will
try before six months are over to convert the readers of the
_Quarterly_ to that heterodox opinion[87].'
Lyell was at that time at work on his review for the _Quarterly_ of
Scrope's _Central France_, and was also completing the 'first sketch'
of the _Principles_. But it is evident that as the result of continued
study of Lamarck's book, Lyell found it, in spite of its fascination, to
embody a theory which he could not but regard as unsound and not
calculated to prove a solution of the great mystery of evolution.
Accordingly when the second volume of the _Principles_ was issued in
1832, it was found to contain in its opening chapters a very trenchant
criticism of Lamarck's theory.
It is only fair to remember, however, that in 1863, after Lyell had
accepted the theory of Natural Selection he wrote to Darwin:
'When I came to the conclusion that after all Lamarck was going
to be shown to be right, and that we must "go the whole orang" I
re-read his book, and remembering when it was written, I felt I
had done him injustice[88].'
It is interesting also to notice that Darwin, like Lyell, gradually came
to entertain a higher opinion of the merit of Lamarck's works, than he
did on his first perusal of them. In 1844, Darwin wrote to Hooker,
'Heaven forfend me from Lamarck nonsense!' and in the same year he
speaks of Lamarck's book as 'veritable rubbish,' an 'absurd though
clever work[89].' When, after the publication of the _Origin of
Species_, Lyell referred to the _conclusions_ arrived at in that work as
similar to those of Lamarck, Darwin expressed something like
indignation, and he wrote to their 'mutual friend' Hooker, 'I have
grumbled a bit in my answer to him' (Lyell) 'at his _always_ classing my
book as a modification of Lamarck's, which it is no more than any author
who did not believe in the immutability of species[90].' In this case,
as is so frequently seen in the writings of Darwin, it is evident that
he attaches infinitely less importance to the establishment of the
_fact_ of the evolution of species, than to the demonstration of a
possible _mode of origin_ of that evolution. But that later in life
Darwin came to take a more indulgent view of the result of Lamarck's
labours is shown by a passage in his 'Historical Sketch' prefixed to the
_Origin_, in 1866. Lamarck, he says, 'first did the eminent service of
arousing attention to the probability of all change in the organic
world, as well as in the inorganic world, being the result of law and
not of miraculous interposition[91].'
In the opinion of Dr Schwalbe and others there are indications in
Darwin's later writings that he had come into much closer relation with
the views of Lamarck, than was the case when he wrote the _Origin_[92].
It is interesting, however, to note that Erasmus Darwin, the grandfather
of Charles, published independently and contemporaneously, views on the
nature and causes of evolution in striking agreement with those of
Lamarck; but perhaps the poetical form, in which he chose to embody his
ideas, led to their receiving less attention than they deserved.
As is now well known a number of writers during the earlier years of the
nineteenth century published statements in favour of evolutionary views,
and in several cases the theory of natural selection was more or less
distinctly outlined. In addition to Geoffroy and Isidore Saint Hilaire
and d'Omalius d'Halloy on the continent, a number of writers in this
country, such as Dr Wells, Mr Patrick Matthew, Dr Pritchard, Professor
Grant, Dean Herbert, all expressed views in favour of evolution, even,
in some cases, foreshadowing Natural Selection as the method. But these
authors attached so little importance to their suggestions, that they
did not even take the trouble to place them on permanent record, and it
is certain that neither Lyell nor Darwin was acquainted with their
writings at the time they were themselves working at the subject.
There was indeed one work which, during the time that the _Origin of
Species_ was in preparation, attracted much popular attention. In 1844,
Robert Chambers, who was favourably known as the author of some
geological papers, wrote a book which excited a great amount of
attention--the well-known _Vestiges of Creation_. This work was a very
bold pronouncement of evolutionary views. Beginning with a statement of
the nebular hypothesis of Kant and Laplace, it discussed the question of
the origin of life--when life became possible on a cooling globe--and,
arguing strongly in favour of the view that all plants and animals, as
the conditions under which they existed change, had given rise to new
forms, better adapted to their environment, insisted that the whole
living creation had been gradually developed from the simplest types.
Chambers published his book anonymously, being naturally afraid of the
prejudices that would be excited against him--especially in his own
country--by a work so outspoken, and it was not till after his death
that its authorship was definitely known.
The _Vestiges of Creation_ met with very different receptions at the
hands of the general public and from the scientific world, at the time
it was published. The former were startled but captivated by its
fearless statements and suggestive lines of thought; while the latter
were repelled and incensed by the want of judgment, too frequently
shown, in accepting as indisputable, facts and experiments which really
rested on a very slender basis or none at all. So popular was the book,
however, that it passed through twelve editions, the last being
published after the appearance of the _Origin of Species_.
It is interesting to read Darwin's judgment in later life on this once
famous book; he says:--
'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[93].'
If we enquire what was the attitude of scientific naturalists towards
the doctrine of Evolution, immediately before the occurrence of the
events to be recorded in the next chapter, we shall find some diversity
of opinion to exist. The late Professor Newton, an eminent
ornithologist, has asserted that, at this period, many systematic
zoologists and botanists had begun to feel great 'searchings of heart'
as to the possibility of maintaining what were the generally prevalent
views concerning the reality and immutability of species. Huxley,
however, declared that he and many contemporary biologists were ready to
say 'to Mosaists and Evolutionists a plague to both your houses!' and
were disposed to turn aside from an interminable and fruitless
discussion, to labour in the fields of ascertainable fact[94].