world； rises into the dignity of pure manhood。 No competent thinker of
the present day dreams of explaining these indubitable facts by the
notion of the existence of unknown and undiscoverable adaptations to
purpose。 And we would remind those who； ignorant of the facts； must be
moved by authority； that no one has asserted the incompetence of the
doctrine of final causes； in its application to physiology and anatomy；
more strongly than our own eminent anatomist； Professor Owen； who；
speaking of such cases； says （'On the Nature of Limbs'； pp。 39； 40）： 〃I
think it will be obvious that the principle of final adaptations fails
to satisfy all the conditions of the problem。〃
But； if the doctrine of final causes will not help us to comprehend the
anomalies of living structure； the principle of adaptation must surely
lead us to understand why certain living beings are found in certain
regions of the world and not in others。 The palm； as we know； will not
grow in our climate； nor the oak in Greenland。 The white bear cannot
live where the tiger thrives； nor 'vice versa'； and the more the
natural habits of animal and vegetable species are examined； the more
do they seem； on the whole； limited to particular provinces。 But when
we look into the facts established by the study of the geographical
distribution of animals and plants it seems utterly hopeless to attempt
to understand the strange and apparently capricious relations which
they exhibit。 One would be inclined to suppose 'a priori' that every
country must be naturally peopled by those animals that are fittest to
live and thrive in it。 And yet how； on this hypothesis； are we to
account for the absence of cattle in the Pampas of South America； when
those parts of the New World were discovered？ It is not that they were
unfit for cattle； for millions of cattle now run wild there； and the
like holds good of Australia and New Zealand。 It is a curious
circumstance； in fact； that the animals and plants of the Northern
Hemisphere are not only as well adapted to live in the Southern
Hemisphere as its own autochthones； but are in many cases absolutely
better adapted； and so overrun and extirpate the aborigines。 Clearly；
therefore； the species which naturally inhabit a country are not
necessarily the best adapted to its climate and other conditions。 The
inhabitants of islands are often distinct from any other known species
of animal or plants （witness our recent examples from the work of Sir
Emerson Tennent； on Ceylon）； and yet they have almost always a sort of
general family resemblance to the animals and plants of the nearest
mainland。 On the other hand； there is hardly a species of fish； shell；
or crab common to the opposite sides of the narrow isthmus of Panama。
Wherever we look； then； living nature offers us riddles of difficult
solution； if we suppose that what we see is all that can be known of it。
But our knowledge of life is not confined to the existing world。
Whatever their minor differences； geologists are agreed as to the vast
thickness of the accumulated strata which compose the visible part of
our earth； and the inconceivable immensity of the time of whose lapse
they are the imperfect； but the only accessible witnesses。 Now；
throughout the greater part of this long series of stratified rocks are
scattered； sometimes very abundantly； multitudes of organic remains；
the fossilized exuviae of animals and plants which lived and died while
the mud of which the rocks are formed was yet soft ooze； and could
receive and bury them。 It would be a great error to suppose that these
organic remains were fragmentary relics。 Our museums exhibit fossil
shells of immeasurable antiquity； as perfect as the day they were
formed； whole skeletons without a limb disturbednay； the changed
flesh； the developing embryos； and even the very footsteps of primieval
organisms。 Thus the naturalist finds in the bowels of the earth
species as well defined as； and in some groups of animals more numerous
than； those that breathe the upper air。 But； singularly enough； the
majority of these entombed species are wholly distinct from those that
now live。 Nor is this unlikeness without its rule and order。 As a
broad fact； the further we go back in time the less the buried species
are like existing forms； and the further apart the sets of extinct
creatures are the less they are like one another。 In other words；
there has been a regular succession of living beings； each younger set
being in a very broad and general sense somewhat more like those which
now live。
It was once supposed that this succession had been the result of vast
successive catastrophes； destructions； and re…creations 'en masse'； but
catastrophes are now almost eliminated from geological； or at least
palaeontological speculation； and it is admitted on all hands that the
seeming breaks in the chain of being are not absolute； but only relative
to our imperfect knowledge； that species have replaced species； not in
assemblages； but one by one； and that； if it were possible to have all
the phenomena of the past presented to us； the convenient epochs and
formations of the geologist； though having a certain distinctness； would
fade into one another with limits as undefinable as those of the
distinct and yet separable colours of the solar spectrum。
Such is a brief summary of the main truths which have been established
concerning species。 Are these truths ultimate and irresolvable facts；
or are their complexities and perplexities the mere expressions of a
higher law？
A large number of persons practically assume the former position to be
correct。 They believe that the writer of the Pentateuch was empowered
and commissioned to teach us scientific as well as other truth； that
the account we find there of the creation of living things is simply
and literally correct； and that anything which seems to contradict it
is； by the nature of the case； false。 All the phenomena which have
been detailed are； on this view； the immediate product of a creative
fiat and consequently are out of the domain of science altogether。
Whether this view prove ultimately to be true or false； it is； at any
rate； not at present supported by what is commonly regarded as logical
proof； even if it be capable of discussion by reason； and hence we
consider ourselves at liberty to pass it by； and to turn to those views
which profess to rest on a scientific basis only； and therefore admit of
being argued to their consequences。 And we do this with the less
hesitation as it so happens that those persons who are practically
conversant with the facts of the case （plainly a considerable advantage）
have always thought fit to range themselves under the latter category。
The majority of these competent persons have up to the present time
maintained two positions；the first； that every species is； within
certain defined or definable limits； fixed and incapable of
modification； the second； that every species was originally produced by
a distinct creative act。 The second position is obviously incapable of
proof or disproof； the direct operations of the Creator not being
subjects of science； and it must therefore be regarded as a corollary
from the first； the truth or falsehood of which is a matter of evidence。
Most persons imagine that the arguments in favour of it are
overwhelming； but to some few minds； and these； it must be confessed；
intellects of no small power and grasp of knowledge； they have not
brought conviction。 Among these minds； that of the famous naturalist
Lamarck； who possessed a greater acquaintance with the lower forms of
life than any man of his day； Cuvier not excepted； and was a good
botanist to boot； occupies a prominent place。
Two facts appear to have strongly affected the course of thought of this
remarkable manthe one； that finer or stronger links of affinity
connect all living beings with one another； and that thus the highest
creature grades by multitudinous steps into the lowest； the other； that
an organ may be developed in particular directions by exerting itself
in particular ways； and that modifications once induced may be
transmitted and become hereditary。 Putting these facts together；
Lamarck endeavoured to account for the first by the operation of the
second。 Place an animal in new circumstances； says he； and its needs
will be altered； the new needs will create new desires； and the attempt
to gratify such desires will result in an appropriate modification of
the organs exerted。 Make a man a blacksmith； and his brachial muscles
will develop in accordance with the demands made upon them； and in like
manner； says Lamarck； 〃the efforts of some short…necked bird to catch
fish without wetting himself have； with time and perseverance； given
rise to all our herons and long…necked waders。〃
The Lamarckian hypothesis has long since been justly condemned； and it
is the established practice for every tyro to raise his heel against
the carcass of the dead lion。 But it is rarely either wise or
instructive to treat even the errors of a really great man with mere
ridicule； and in the present case the logical form of the doctrine
stan