As for Ab's own name, it came from no personal mark or peculiarity or as the result of any particular incident of his babyhood. It was merely a convenient adaptation by his parents of a childish expression of his own, a labial attempt to say something. His mother had mimicked his babyish prattlings, the father had laughed over the mimicry, and, almost unconsciously, they referred to their baby afterward as "Ab," until it grew into a name which should be his for life. There was no formal early naming of a child in those days; the name eventually made itself, and that was all there was to it. There was, for instance, a child living not many miles away, destined to be a future playmate and ally of Ab, who, though of nearly the same age, had not yet been named at all. His title, when he finally attained it, was merely Oak. This was not because he was straight as an oak, or because he had an acorn birthmark, but because adjoining the cave where he was born stood a great oak with spreading limbs, from one of which was dangled a rude cradle, into which the babe was tied, and where he would be safe from all attacks during the absence of his parents on such occasions as they did not wish the burden of carrying him about. "Rock-a-by-baby upon the tree-top" was often a reality in the time of the cave men. Ab was fortunate in being born at a reasonably comfortable stage of the world's history. He had a decent prospect as to clothing and shelter, and there was abundance of food for those brave enough or ingenious enough to win it. The climate was not enervating. There were cold times for the people of the epoch and, in their seasons, harsh and chilling winds swept over bare and chilling glaciers, though a semi-tropical landscape was all about. So suddenly had come the change from frigid cold to moderate warmth, that the vast fields of ice once moving southward were not thawed to their utmost depths even when rank vegetation and a teeming life had sprung up in the now European area, and so it came that, in some places, cold, white monuments and glittering plateaus still showed themselves amid the forest and fed the tumbling streams which made the rivers rushing to the ocean. There were days of bitter cold in winter and sultry heat in summer.