Note also that one toe has been altogether discarded by birds as superfluous.  The germ, or bud, must be there, for the Dorking fowl has produced a fifth toe under some influence of the poultry-yard, but no natural bird has more than four.  Except in swifts, which never perch, but cling to rocks and walls, one is turned backwards, and, by a cunning contrivance, the act of bending the leg draws them all automatically together.  So a hen closes its toes at every step it takes, as if it grasped something, and, of course, when it settles down on its roost, they grasp that tight and hold it fast till morning.  But to birds that do not perch this mechanism is only an encumbrance, so many of them, like the plovers, abolish the hind toe entirely, and the prince of all two-legged runners, the ostrich, has got rid of one of the front toes also, retaining only two.

[Illustration:  THESE BEASTS ARE ALL CLODHOPPERS, AND THEIR FEET ARE HOBNAILED BOOTS.]

To a man who thinks, it is very interesting to observe that beasts have been led along gradually in the very same direction.  All the common beasts, such as cats, dogs, rats, stoats, and so on, have five ordinary toes.  On the hind feet there may be only four.  But as soon as we come to those that feed on grass and leaves, standing or walking all the while, we find that the feet are shod with hoofs instead of being tipped with claws.  First the five toes, though clubbed together, have each a separate hoof, as in the elephant; then the hippopotamus follows with four toes, and the rhinoceros with practically three.  These beasts are all clodhoppers, and their feet are hobnailed boots.  The more active deer and all cattle keep only two toes for practical purposes, though stumps of two more remain.  Finally, the horse gathers all its foot into one boot, and becomes the champion runner of the world.

It is not without significance that this degeneracy of the feet goes with a decline in the brain, whether as cause or effect I will not pretend to know.  These hoofed beasts have shallow natures and live shallow lives.  They eat what is spread by Nature before their noses, have no homes, and do nothing but feed and fight with each other.  The elephant is a notable exception, but then the nose of the elephant, becoming a hand, has redeemed its mind.  As for the horse, whatever its admirers may say, it is just a great ass.  There is a lesson in all this:  “from him that hath not shall be taken even that which he hath.”

There is another dull beast which, from the point of view of the mere systematist, seems as far removed from those that wear hoofs as it could be, but the philosopher, considering the point at which it has arrived, rather than the route by which it got there, will class it with them, for its idea of life is just theirs turned topsy-turvy.  The nails of the sloth, instead of being hammered into hoofs on the hard ground, have grown long and curved, like those of a caged bird, and become hooks by which it can hang, without effort, in the midst of the leaves on which it feeds.  A minimum of intellect is required for such an existence, and the sloth has lost any superfluous brain that it may have had, as well as two, or even three, of its five toes.