s more valuable than the European
_Hipparion_ for the reason that it is devoid of some of the
peculiarities of that form--peculiarities 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 toes--one 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 anchitheroid in pattern.

But the most important discovery of all is the _Orohippus_, which comes
from the Eocene formation, and which 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;[6] 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 scienti