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Well； if you go back in time； you find some of the older； now extinct；
allies of the ruminants have well…developed teeth in their upper jaws；
and at the present day the pig （which is in structure closely connected
with ruminants） has well…developed teeth in its upper jaw； so that here
is another instance of organs well…developed and very useful； in one
animal； represented by rudimentary organs； for which we can discover no
purpose whatsoever； in another closely allied animal。 The whalebone
whale； again； has horny 〃whalebone〃 plates in its mouth； and no teeth；
but the young foetal whale； before it is born； has teeth in its jaws；
they； however； are never used； and they never come to anything。 But
other members of the group to which the whale belongs have
well…developed teeth in both jaws。
Upon any hypothesis of special creation； facts of this kind appear to me
to be entirely unaccountable and inexplicable； but they cease to be so
if you accept Mr。 Darwin's hypothesis； and see reason for believing
that the whalebone whale and the whale with teeth in its mouth both
sprang from a whale that had teeth； and that the teeth of the foetal
whale are merely remnantsrecollections； if we may so sayof the
extinct whale。 So in the case of the horse and the rhinoceros： suppose
that both have descended by modification from some earlier form which
had the normal number of toes； and the persistence of the rudimentary
bones which no longer support toes in the horse becomes comprehensible。
In the language that we speak in England； and in the language of the
Greeks； there are identical verbal roots； or elements entering into the
composition of words。 That fact remains unintelligible so long as we
suppose English and Greek to be independently created tongues； but when
it is shown that both languages are descended from one original； the
Sanscrit； we give an explanation of that resemblance。 In the same way
the existence of identical structural roots； if I may so term them；
entering into the composition of widely different animals； is striking
evidence in favour of the descent of those animals from a common
original。
To turn to another kind of illustration：If you regard the whole series
of stratified rocksthat enormous thickness of sixty or seventy
thousand feet that I have mentioned before； constituting the only
record we have of a most prodigious lapse of time； that time being； in
all probability； but a fraction of that of which we have no record；if
you observe in these successive strata of rocks successive groups of
animals arising and dying out； a constant succession； giving you the
same kind of impression； as you travel from one group of strata to
another； as you would have in travelling from one country to
another；when you find this constant succession of forms； their traces
obliterated except to the man of science；when you look at this
wonderful history； and ask what it means； it is only a paltering with
words if you are offered the reply；'They were so created。'
But if； on the other hand； you look on all forms of organized beings as
the results of the gradual modification of a primitive type； the facts
receive a meaning； and you see that these older conditions are the
necessary predecessors of the present。 Viewed in this light the facts
of palaeontology receive a meaningupon any other hypothesis； I am
unable to see； in the slightest degree； what knowledge or signification
we are to draw out of them。 Again； note as bearing upon the same
point； the singular likeness which obtains between the successive
Faunae and Florae； whose remains are preserved on the rocks： you never
find any great and enormous difference between the immediately
successive Faunae and Florae； unless you have reason to believe there
has also been a great lapse of time or a great change of conditions。
The animals； for instance； of the newest tertiary rocks； in any part of
the world； are always； and without exception； found to be closely
allied with those which now live in that part of the world。 For
example； in Europe； Asia； and Africa； the large mammals are at present
rhinoceroses； hippopotamuses； elephants； lions； tigers； oxen； horses；
etc。； and if you examine the newest tertiary deposits； which contain
the animals and plants which immediately preceded those which now exist
in the same country； you do not find gigantic specimens of ant…eaters
and kangaroos； but you find rhinoceroses； elephants； lions； tigers；
etc。；of different species to those now living；but still their close
allies。 If you turn to South America； where； at the present day； we
have great sloths and armadilloes and creatures of that kind； what do
you find in the newest tertiaries？ You find the great sloth…like
creature； the 'Megatherium'； and the great armadillo； the 'Glyptodon'；
and so on。 And if you go to Australia you find the same law holds
good； namely； that that condition of organic nature which has preceded
the one which now exists； presents differences perhaps of species； and
of genera； but that the great types of organic structure are the same
as those which now flourish。
What meaning has this fact upon any other hypothesis or supposition than
one of successive modification？ But if the population of the world； in
any age； is the result of the gradual modification of the forms which
peopled it in the preceding age；if that has been the case； it is
intelligible enough； because we may expect that the creature that
results from the modification of an elephantine mammal shall be
something like an elephant； and the creature which is produced by the
modification of an armadillo…like mammal shall be like an armadillo。
Upon that supposition； I say； the facts are intelligible； upon any
other； that I am aware of； they are not。
So far； the facts of palaeontology are consistent with almost any form
of the doctrine of progressive modification； they would not be
absolutely inconsistent with the wild speculations of De Maillet； or
with the less objectionable hypothesis of Lamarck。 But Mr。 Darwin's
views have one peculiar merit； and that is； that they are perfectly
consistent with an array of facts which are utterly inconsistent with
and fatal to； any other hypothesis of progressive modification which
has yet been advanced。 It is one remarkable peculiarity of Mr。
Darwin's hypothesis that it involves no necessary progression or
incessant modification； and that it is perfectly consistent with the
persistence for any length of time of a given primitive stock；
contemporaneously with its modifications。 To return to the case of the
domestic breeds of pigeons； for example； you have the Dove…cot pigeon；
which closely resembles the Rock pigeon； from which they all started；
existing at the same time with the others。 And if species are
developed in the same way in nature； a primitive stock and its
modifications may； occasionally； all find the conditions fitted for
their existence； and though they come into competition； to a certain
extent； with one another； the derivative species may not necessarily
extirpate the primitive one； or 'vice versa'。
Now palaeontology shows us many facts which are perfectly h