If the races of men should suddenly disappear from the earth, leaving only the animals, great changes would take place. For a time, the works of men would remain, but gradually the lofty buildings in our cities would crumble and collapse, the railroads would become thin lines of rusty steel buried in tangles of weeds, farms would be covered with brush and with great forests, the roads would become merely paths for animals, and in place of fertile fields and villages and busy cities the ancient jungle would return. External Nature would remain much the same as now. Season would succeed season, the rivers would flow as majestically as ever to the sea, the moon and stars would shine or would be blotted out by great storms; the woods would be filled

with the music of bird song or the fragrance of flowers, or, in winter, would be clothed in their mantle of snow. And the animal world would be much the same as now, except that the wild beasts would become bolder and more numerous and the animals that man has tamed or has made his companions would become wild or would be destroyed by enemies of their own kind.

In such a world, no more progress of the sort that seems progress to us would be possible. Animals would not build cities or make inventions or use telephones or trains or ships. There would still be such primitive methods of living as animals The races of animals would still keep up some such form of communication as they now seem to have. Cats, for example, look much alike, no matter what their breed, yet they know each other and have

use.

their quarrels and their methods of getting on with each other. Dogs differ from each other in appearance more than most other animals, yet dogs of every kind recognize each other and have some means of communication. But no coöperation, working together for a safer and happier mode of living, comes from this faint sense of relationship that members of an animal-race feel for one another.

One reason for this failure is that the imagination and memory of animals are very small. We have no evidence that the beauty of Nature—a vista in a forest or the grandeur of mountains or the tang of the salt spray-produces any effect on the animals that look upon or hear or feel Nature's wonders. Many of them have, to be sure, primitive ways of expressing their satisfaction over a good meal or a warm, sunny spot, or their discomfort when they are hurt or are deprived of something that they want. Birds seem to enjoy the music they make, and a great poet once said that it was his faith that every flower enjoys the air it breathes. But so far as we know, all the reactions of animals to what goes on about them are confined to the moment and are of the simplest kind. They know nothing of distant lands, unless they belong to animal races that migrate from place to place in search of food or in order to escape extreme cold or extreme heat. They have no records of their past history

-no books or poems or permanent records of any kind. If mankind were to disappear from the earth, the horse and the cow and the dog and all the tribes of animals domesticated by man, would soon forget that a strange superior animal, walking upright and having uncanny powers over them, had ever used them for his pleasure or his profit, had ever cared for them in sheds and barns when they were tired, or had ever killed them for his own food when he was hungry.

Man differs from the animals, then, chiefly in his power to ask questions of life and to get answers to his questions. He could project his thought more rapidly than he could walk, so he discovered means of transporting himself to places where he wanted to be. He used the ox and the horse to multiply his strength;

when these were found wanting, he invented machines that would carry him still more rapidly-the ship, the train of cars running on ribbons of steel, the automobile, the airplane. He was not satisfied with his power of communicating his thought to those of his fellows who were near by, so he discovered how to send his voice over thousands of miles by the aid of a slender wire, and then how to send it without even the wire. He communicated his thoughts by a system of sounds that he developed with great precision, and then by representing these sounds on various materials-stone, bark, paper made of reeds, later on fabrics of finer qualities. He represented his ideas of the beauty of Nature by pictures that he drew on stone, or on canvas; at length he discovered how to send his pictures through space by telephone. He lived in huts or caves, then in tents that he could carry about with him, still later, if he desired, in houses that could fly with incredible speed on rails. In order to increase his powers he enlarged his group of associates, which at first was like the group of animals, so that thousands, even millions, of his kind could live within a small area in buildings not built on one level but on ten or twenty or fifty levels. And he kept records of his deeds, and of his thoughts, and of his ideas of the beauty of Nature and life, so that he could live in the past as well as in the present, and could learn from generations long dead.

Now all this may be summed up by saying that man is so constituted that he can reflect about the things that surround him. The reactions of animals are simple, are limited to the moment. Man seizes on what is of service to him, and can determine how to make this even more serviceable. He can project his mind into the world about him or into the past or the future, can see what he wishes to bring to pass, and can set about making it possible; or he can see what he wishes to preserve of the past for his present or future profit and enjoyment. He can live more lives than

one.

He multiplies himself in a thousand ways. He makes all things serve him. He explores the mysteries of Nature, the sources of life, and the causes of death.