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species of Palaeotherium。 Hence； in attempting to trace
the pedigree of the horse beyond the Miocene epoch and the
Anchitheroid form； I naturally sought among the various species
of Palaeotheroid animals for its nearest ally； and I was led to
conclude that the Palaeotherium minus （Plagiolophus）
represented the next step more nearly than any form then known。
I think that this opinion was fully justifiable； but the
progress of investigation has thrown an unexpected light on the
question； and has brought us much nearer than could have been
anticipated to a knowledge of the true series of the progenitors
of the horse。
You are all aware that； when your country was first discovered
by Europeans； there were no traces of the existence of the horse
in any part of the American Continent。 The accounts of the
conquest of Mexico dwell upon the astonishment of the natives of
that country when they first became acquainted with that
astounding phenomenona man seated upon a horse。
Nevertheless； the investigations of American geologists have
proved that the remains of horses occur in the most superficial
deposits of both North and South America； just as they do in
Europe。 Therefore； for some reason or otherno feasible
suggestion on that subject； so far as I know； has been madethe
horse must have died out on this continent at some period
preceding the discovery of America。 Of late years there has been
discovered in your Western Territories that marvellous
accumulation of deposits； admirably adapted for the preservation
of organic remains； to which I referred the other evening； and
which furnishes us with a consecutive series of records of the
fauna of the older half of the Tertiary epoch； for which we have
no parallel in Europe。 They have yielded fossils in an excellent
state of conservation and in unexampled number and variety。
The researches of Leidy and others have shown that forms allied
to the Hipparion and the Anchitherium are to be
found among these remains。 But it is only recently that the
admirably conceived and most thoroughly and patiently worked…out
investigations of Professor Marsh have given us a just idea of
the vast fossil wealth； and of the scientific importance； of
these deposits。 I have had the advantage of glancing over the
collections in Yale Museum； and I can truly say that； so far as
my knowledge extends； there is no collection from any one region
and series of strata comparable； for extent； or for the care
with which the remains have been got together； or for their
scientific importance； to the series of fossils which he has
deposited there。 This vast collection has yielded evidence
bearing upon the question of the pedigree of the horse of the
most striking character。 It tends to show that we must look to
America； rather than to Europe； for the original seat of the
equine series； and that the archaic forms and successive
modifications of the horse's ancestry are far better preserved
here than in Europe。
Professor Marsh's kindness has enabled me to put before you a
diagram； every figure in which is an actual representation of
some specimen which is to be seen at Yale at this present time
（Fig。 9）。
Fig。 9。
The succession of forms which he has brought together carries us
from the top to the bottom of the Tertiaries。 Firstly； there is
the true horse。 Next we have the American Pliocene form of the
horse （Pliohippus）； in the conformation of its limbs it
presents some very slight deviations from the ordinary horse；
and the crowns of the grinding teeth are shorter。 Then comes the
Protohippus； which represents the European
Hipparion； having one large digit and two small ones on
each foot； and the general characters of the fore…arm and leg to
which I have referred。 But it is more valuable than the European
Hipparion for the reason that it is devoid of some of the
peculiarities of that formpeculiarities which tend to show
that the European Hipparion is rather a member of a
collateral branch； than a form in the direct line of succession。
Next； in the backward order in time； is the Miohippus；
which corresponds pretty nearly with the Anchitherium of
Europe。 It presents three complete toesone large median and
two smaller lateral ones； and there is a rudiment of that digit；
which answers to the little finger of the human hand。
The European record of the pedigree of the horse stops here；
in the American Tertiaries； on the contrary； the series of
ancestral equine forms is continued into the Eocene formations。
An older Miocene form； termed Mesohippus； has three toes
in front； with a large splint…like rudiment representing the
little finger； and three toes behind。 The radius and ulna； the
tibia and the fibula； are distinct； and the short crowned molar
teeth are anchitherioid in pattern。
But the most important discovery of all is the Orohippus；
which comes from the Eocene formation； and is the oldest member
of the equine series； as yet known。 Here we find four complete
toes on the front limb； three toes on the hind limb； a well…
developed ulna； a well…developed fibula； and short…crowned
grinders of simple pattern。
Thus； thanks to these important researches； it has become
evident that； so far as our present knowledge extends； the
history of the horse…type is exactly and precisely that which
could have been predicted from a knowledge of the principles of
evolution。 And the knowledge we now possess justifies us
completely in the anticipation； that when the still lower Eocene
deposits； and those which belong to the Cretaceous epoch； have
yielded up their remains of ancestral equine animals； we shall
find； first； a form with four complete toes and a rudiment of
the innermost or first digit in front； with； probably； a
rudiment of the fifth digit in the hind foot； while； in still
older forms； the series of the digits will be more and more
complete； until we come to the five…toed animals； in which； if
the doctrine of evolution is well founded； the whole series must
have taken its origin。
That is what I mean by demonstrative evidence of evolution。
An inductive hypothesis is said to be demonstrated when the
facts are shown to be in entire accordance with it。 If that is
not scientific proof； there are no merely inductive conclusions
which can be said to be proved。 And the doctrine of evolution；
at the present time； rests upon exactly as secure a foundation
as the Copernican theory of the motions of the heavenly bodies
did at the time of its promulgation。 Its logical basis is
precisely of the same characterthe coincidence of the observed
facts with theoretical requirements。
The only way of escape； if it be a way of escape； from the
conclusions which I have just indicated； is the supposition that
all these different equine forms have been created separately at
separate epochs of time； and； I repeat； that of such an
hypothesis as this there neither is； nor can be； any scientific
evidence； and； assuredly； so far as I know； there is none which
is supported； or pretends to be supported； by evidence or
authority of any other kind。 I can but think that the time will
come when such suggestions as these； such obvious attempts to
escape the force of demonstration； will be put upon the same
footing as the supposition made by some writers； who are I
believe not completely extinct at present； that fossils are mere
simulacra； are no indications of the former existence of the
animals to which they seem to belong； but that they are either
sports of nature； or special creations； intendedas I heard
suggested the other dayto test our faith。
In fact； the whole evidence is in favour of evolution； and there
is none against it。 And I say this； although perfectly well
aware of the seeming difficulties which have been built up upon
what appears to the uninformed to be a solid foundation。 I meet
constantly with the argument that the doctrine of evolution
cannot be well founded； because it requires the lapse of a very
vast period of time； while the duration of life upon the earth
thus implied is inconsistent with the conclusions arrived at by
the astronomer and the physicist。 I may venture to say that I am
familiar with those conclusions； inasmuch as some years ago；
when President of the Geological Society of London； I took the
liberty of criticising them； and of showing in what respects； as
it appeared to me； they lacked complete and thorough
demonstration。 But； putting that point aside； suppose that； as
the astronomers； or some of them； and some physical
philosophers； tell us； it is impossible that life could have
endured upon the earth for as long a period as is required by
the doctrine of evolutionsupposing that to be provedI desire
to be informed； what is the foundation for the statement that
evolution does