s which
passed from the earth millions of years ago. In most cases the
splint-bones have no function whatever to perform. They are indeed
superfluous and injurious parts, and are likely from time to time to be
worse than useless, becoming the seats of disease. In this beautiful
instance, perhaps the fairest of all those showing how the highly
developed forms of our time retain a memory of their ancestral life, we
see how the advance in the series of the horse has been effected against
the resistance ancient organic habit opposes to all gains. We can
therefore the better understand how the building of the hoof represents
the labor of geologic ages during which the slow-made gains were won.

In its present elaborate form, the hoof of a horse is the most perfect
instrument of support which has been devised in the animal kingdom to
uphold a large and swiftly moving animal in its passage over the
ground. The original toe-nail, and the neighboring soft parts connected
with it, have been modified into a structure which in an extraordinary
manner combines solidity with elasticity, so that it may strike violent
blows upon the hard surface of the earth without harm. The bones of the
toe to which it is affixed have enlarged with the progressive loss of
their neighbors of the extremity, until they fairly continue the
dimensions of the bony parts of the leg. Moreover, they have lengthened
out, so as to give the limb a great extension, and this, in turn,
magnifies the stride which the creature can take in running. The result
is that the horse can carry a greater weight at a swifter speed than
any other animal approaching it in size.

[Illustration: On Rotten Row, Hyde Park, London]

The needs which led, in a slow accumulative way, to the invention of
the admirable contrivance of the horse's foot, were doubtless founded
on the necessities of swift movement in fleeing from the great
predaceous animals. Incidentally, however, as this development has
gone on, the peculiarities of the extremity have proved highly
advantageous in defence, and the creatures have acquired certain
peculiar ways of using their feet effectively to this end. The solid
character of the hoof, its considerable weight, and the great power
of the muscles of the hams, which are the principal agents in
propelling the animal, make the hind feet capable of delivering a
very powerful blow. The measure of its efficiency may be judged from
the fact that a lion has been s