Yet later we have the Mesohippus or half-way horse.  There are still three toes on the hind foot, but one more of the fingers of the forefeet has disappeared.  This time it is the little finger that goes, leaving only a small bone to show that its going was by a slow shrinking.  The creature now has three little hoofs on each of its feet.

Still nearer our own time comes the Miohippus, which shows the two side hoofs on each foot shrinking up so that they do not touch the ground, but they still bear little hoofs.  Lastly, about the time of man’s coming on the earth, appears his faithful servant, the horse, in which those little side hoofs have disappeared, leaving only two little “splint” bones to mark the place where these side hoofs belong.  Thus, step by step, our horses’ feet were built up; while these parts were changing, the other parts of the animals were also slowly altering.  They were at first smaller than our horses,—­some of them not as large as an ordinary Newfoundland dog; others as small as foxes.

[Illustration:  FIG. 11.  DEVELOPMENT OF HORSES’S FOOT.]

As if to remind us of his old shape, our horses now and then, but rarely, have, in place of the little splint bones above the hoof, two smaller hoofs, just like the foot of Miohippus.  Sometimes these are about the size of a silver dollar, on the part that receives the shoe when horses are shod.

In this way, by slow-made changes, the early mammals pass into the higher.  Out of one original part are made limbs as different as the feet of the horse, the wing of a bat, the paddle of a whale, and the hand of man.  So with all the parts of the body the forms change to meet the different uses to which they are put.

At the end of this long promise, which was written in the very first animals, comes man himself, in form closely akin to the lower animals, but in mind immeasurably apart from them.  We can find every part of man’s body in a little different shape in the monkeys, but his mind is of a very different quality.  While his lower kindred cannot be made to advance in intelligence any more than man himself can grow a horse’s foot or a bat’s wing, he is constantly going higher and higher in his mental and moral growth.

So far we have found but few traces of man that lead us to suppose that he has been for a long geological time on the earth, yet there is good evidence that he has been here for a hundred thousand years or more.  It seems pretty clear that he has changed little in his body in all these thousands of generations.  The earliest remains show us a large-brained creature, who used tools and probably had already made a servant of fire, which so admirably aids him in his work.