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to be informed； what is the foundation for the statement that
evolution does require so great a time？ The biologist knows
nothing whatever of the amount of time which may be required for
the process of evolution。 It is a matter of fact that the equine
forms which I have described to you occur； in the order stated；
in the Tertiary formations。 But I have not the slightest means
of guessing whether it took a million of years； or ten millions；
or a hundred millions； or a thousand millions of years； to give
rise to that series of changes。 A biologist has no means of
arriving at any conclusion as to the amount of time which may be
needed for a certain quantity of organic change。 He takes his
time from the geologist。 The geologist； considering the rate at
which deposits are formed and the rate at which denudation goes
on upon the surface of the earth； arrives at more or less
justifiable conclusions as to the time which is required for the
deposit of a certain thickness of rocks； and if he tells me that
the Tertiary formations required 500；000；000 years for their
deposit； I suppose he has good ground for what he says； and I
take that as a measure of the duration of the evolution of the
horse from the Orohippus up to its present condition。
And； if he is right； undoubtedly evolution is a very slow
process； and requires a great deal of time。 But suppose； now；
that an astronomer or a physicistfor instance； my friend Sir
William Thomsontells me that my geological authority is quite
wrong； and that he has weighty evidence to show that life could
not possibly have existed upon the surface of the earth
500；000；000 years ago； because the earth would have then been
too hot to allow of life； my reply is： 〃That is not my affair；
settle that with the geologist； and when you have come to an
agreement among yourselves I will adopt your conclusion。〃
We take our time from the geologists and physicists； and it is
monstrous that； having taken our time from the physical
philosopher's clock； the physical philosopher should turn round
upon us； and say we are too fast or too slow。 What we desire to
know is； is it a fact that evolution took place？ As to the
amount of time which evolution may have occupied； we are in the
hands of the physicist and the astronomer； whose business it is
to deal with those questions。
I have now； ladies and gentlemen； arrived at the conclusion of
the task which I set before myself when I undertook to deliver
these lectures。 My purpose has been； not to enable those among
you who have paid no attention to these subjects before； to
leave this room in a condition to decide upon the validity or
the invalidity of the hypothesis of evolution； but I have
desired to put before you the principles upon which all
hypotheses respecting the history of Nature must be judged；
and furthermore； to make apparent the nature of the evidence and
the amount of cogency which is to be expected and may be
obtained from it。 To this end； I have not hesitated to regard
you as genuine students and persons desirous of knowing the
truth。 I have not shrunk from taking you through long
discussions； that I fear may have sometimes tried your patience；
and I have inflicted upon you details which were indispensable；
but which may well have been wearisome。 But I shall rejoiceI
shall consider that I have done you the greatest service which
it was in my power to doif I have thus convinced you that the
great question which we have been discussing is not one to be
dealt with by rhetorical flourishes； or by loose and superficial
talk； but that it requires the keen attention of the trained
intellect and the patience of the accurate observer。
When I commenced this series of lectures； I did not think it
necessary to preface them with a prologue； such as might be
expected from a stranger and a foreigner； for during my brief
stay in your country； I have found it very hard to believe that
a stranger could be possessed of so many friends； and almost
harder that a foreigner could express himself in your language
in such a way as to be； to all appearance； so readily
intelligible。 So far as I can judge； that most intelligent； and
perhaps； I may add； most singularly active and enterprising
body； your press reporters； do not seem to have been deterred by
my accent from giving the fullest account of everything that I
happen to have said。
But the vessel in which I take my departure to…morrow morning is
even now ready to slip her moorings； I awake from my delusion
that I am other than a stranger and a foreigner。 I am ready to
go back to my place and country； but； before doing so； let me；
by way of epilogue； tender to you my most hearty thanks for the
kind and cordial reception which you have accorded to me；
and let me thank you still more for that which is the greatest
compliment which can be afforded to any person in my position
the continuous and undisturbed attention which you have bestowed
upon the long argument which I have had the honour to lay
before you。
FOOTNOTES
（1） The absence of any keel on the breast…bone and some other
osteological peculiarities； observed by Professor Marsh；
however； suggest that Hesperornis may be a modification
of a less specialised group of birds than that to which these
existing aquatic birds belong。
（2） A second specimen； discovered in 1877； and at present in the
Berlin museum； shows an excellently preserved skull with teeth；
and three digits； all terminated by claws； in the fore limb。
1893。
（3）I use the word 〃type〃 because it is highly probable that many
forms of Anchitherium…like and Hipparion…like
animals existed in the Miocene and Pliocene epochs； just as many
species of the horse tribe exist now； and it is highly
improbable that the particular species of Anchitherium or
Hipparion； which happen to have been discovered； should
be precisely those which have formed part of the direct line of
the horse's pedigree。
（4） Since this lecture was delivered； Professor Marsh has
discovered a new genus of equine mammals （Eohippus） from
the lowest Eocene deposits of the West； which corresponds very
nearly to this description。American Journal of Science；
November； 1876。
End