His senses were being honed to a fine edge. He stored knowledge thirstily. He understood love, marriage, customs, anger, pity, rage, selfishness, shadings and subtleties, realities and reflections. One thing suggested another. The sight of green plant life whirled his mind like a gyroscope, seeking balance in a world where lack of time for explanations made a mind seek and interpret on its own. The soft burden of food gave him knowledge of his system, of energy, of movement. Like a bird newly cracking its way from a shell, he was almost a unit, complete, all-knowing. Heredity had done all this for him. He grew excited with his ability. * * * * * They walked, mother, father and the two children, smelling the smells, watching the birds bounce from wall to wall of the valley like scurrying pebbles and suddenly the father said a strange thing: "Remember?" Remember what? Sim lay cradled. Was it any effort for them to remember when they'd lived only seven days! The husband and wife looked at each other. "Was it only three days ago?" said the woman, her body shaking, her eyes closing to think. "I can't believe it. It is so unfair." She sobbed, then drew her hand across her face and bit her parched lips. The wind played at her gray hair. "Now is my turn to cry. An hour ago it was you!" "An hour is half a life." "Come," she took her husband's arm. "Let us look at everything, because it will be our last looking." "The sun'll be up in a few minutes," said the old man. "We must turn back now." "Just one more moment," pleaded the woman. "The sun will catch us." "Let it catch me then!" "You don't mean that." "I mean nothing, nothing at all," cried the woman. The sun was coming fast. The green in the valley burnt away. Searing wind blasted from over the cliffs. Far away where sun bolts hammered battlements of cliff, the huge stone faces shook their contents; those avalanches not already powdered down, were now released and fell like mantles. "Dark!" shouted the father. The girl sprang over the warm floor of the valley, answering, her hair a black flag behind her. Hands full of green fruits, she joined them. The sun rimmed the horizon with flame, the air convulsed dangerously with it, and whistled. The cave people bolted, shouting, picking up their fallen children, bearing vast loads of fruit and grass with them back to their deep hideouts. In moments the valley was bare. Except for one small child someone had forgotten. He was running far out on the flatness, but he was not strong enough, and the engulfing heat was drifting down from the cliffs even as he was half across the valley. Flowers were burnt into effigies, grasses sucked back into rocks like singed snakes, flower seeds whirled and fell in the sudden furnace blast of wind, sown far into gullies and crannies, ready to blossom at sunset tonight, and then go to seed and die again.