A great fear came upon him. This was more of the terrible unknown. He crouched down on the lip of the cave and gazed out on the world. He was very much afraid. Because it was unknown, it was hostile to him. Therefore the hair stood up on end along his back and his lips wrinkled weakly in an attempt at a ferocious and intimidating snarl. Out of his puniness and fright he challenged and menaced the whole wide world. Nothing happened. He continued to gaze, and in his interest he forgot to snarl. Also, he forgot to be afraid. For the time, fear had been routed by growth, while growth had assumed the guise of curiosity. He began to notice near objects—an open portion of the stream that flashed in the sun, the blasted pine-tree that stood at the base of the slope, and the slope itself, that ran right up to him and ceased two feet beneath the lip of the cave on which he crouched. Now the grey cub had lived all his days on a level floor. He had never experienced the hurt of a fall. He did not know what a fall was. So he stepped boldly out upon the air. His hind-legs still rested on the cave-lip, so he fell forward head downward. The earth struck him a harsh blow on the nose that made him yelp. Then he began rolling down the slope, over and over. He was in a panic of terror. The unknown had caught him at last. It had gripped savagely hold of him and was about to wreak upon him some terrific hurt. Growth was now routed by fear, and he ki-yi’d like any frightened puppy. The unknown bore him on he knew not to what frightful hurt, and he yelped and ki-yi’d unceasingly. This was a different proposition from crouching in frozen fear while the unknown lurked just alongside. Now the unknown had caught tight hold of him. Silence would do no good. Besides, it was not fear, but terror, that convulsed him. But the slope grew more gradual, and its base was grass-covered. Here the cub lost momentum. When at last he came to a stop, he gave one last agonised yell and then a long, whimpering wail. Also, and quite as a matter of course, as though in his life he had already made a thousand toilets, he proceeded to lick away the dry clay that soiled him. After that he sat up and gazed about him, as might the first man of the earth who landed upon Mars. The cub had broken through the wall of the world, the unknown had let go its hold of him, and here he was without hurt. But the first man on Mars would have experienced less unfamiliarity than did he. Without any antecedent knowledge, without any warning whatever that such existed, he found himself an explorer in a totally new world.