He was a silent fury who no torment could tame.

The pitch to which he was aroused was tremendous. All the fighting blood of his breed was up in him and surging through him. This was living., though he did not know it. He was realizing his own meaning in the world; he was doing that for which he was made.... He was justifying his existence, than which life can do no greater; for life achieves its summit when it does to the uttermost that which it was equipped to do.

Thus it was that in obedience to the law laid down by his mother, and in obedience to the law of that unknown and nameless thing, fear, he kept away from the mouth of the cave.

The human race is doomed to sink back farther and farther into the primitive night ere again it begins its bloody climb upward to civilization.

[Speaking to a group of wealthy New Yorkers] A million years ago, the cave man, without tools, with small brain, and with nothing but the strength of his body, managed to feed his wife and children, so that through him the race survived. You on the other hand, armed with all the modern means of production, multiplying the productive capacity of the cave man a million times — you are incompetents and muddlers, you are unable to secure to millions even the paltry amount of bread that would sustain their physical life. You have mismanaged the world, and it shall be taken from you.

He had no conscious knowledge of death, but like every animal of the Wild, he possessed the instinct of death. To him it stood as the greatest of hurts. It was the very essence of the unknown; it was the sum of the terrors of the unknown, the one culminating and unthinkable catastrophe that could happen to him, about which he knew nothing and about which he feared everything.

Had the cub thought in man-fashion, he might have epitomized life as a voracious appetite, and the world as a place wherein ranged a multitude of appetites, pursuing and being pursued, hunting and being hunted, eating and being eaten, all in blindness and confusion, with violence and disorder, a chaos of gluttony and slaughter, ruled over by chance, merciless, planless, endless.