have counted the times. A factor was missing—dimly he knew that. The sun was dull red along the valley when he desisted; his hands were raw and bleeding, and seeing that, a sound rose in his throat like grating gravel.

Grimly, he buried his stone there beneath the bole and made his way back to the great ledge. His share of Obe would last yet a day or two. The thought of food was only fleeting, because the anger was still inside him, larger now, demanding now ... that thing-that-prodded.

Obe was gone at last, both Gral's share and all the rest. Three days were gone and Gral did not try to bring again. But each day he went from the ledge in advance of the others, he went in a hunger he did not heed—to the place of the buried stone.

On the third day he thought that Otah followed, keeping discreetly behind; but he could not be sure. This was not Otah's usual direction. And later, on the far shore across the shallows he saw one of Kurho's tribe from Far End. It was not often that Kurho's people foraged this far, and Gral could not say how long the man must have stood there bold and brazen. When next he looked up, the fellow was gone.

Ordinarily he would have reported this to Gor-wah, but the incident was soon forgotten. He continued doggedly with shaft and stone. It was something wild and febrile that drove him now, and he could not have wondered at his own incredible quixotism—he was a million years removed from that! But inevitably his synapses took hold, the neuronic links grooved, and to Gral one thought emerged: the vines would never do.

And so he came to know where the missing factor lay. He knew it dully and was helpless.

More than helpless, he was hungry. It came with a great gnawing need. On the fifth day it was Otah who noticed, and more out of contempt than pity tossed him the remnants of a wild-dog he had brought: the portion was little more than stripped bones and sinew, but Gral accepted without question, crawled to his place on the ledge and partially assuaged his hunger....

The ways of discovery are most wondrous—yet who will dare to say they take precedence over the wondrous ways of the stomach? And the ways are ironic; is it not conceivable that the two should align in devious fruition? For Gral found answer, not in his groping hands, but tangled about his clumsy feet!

The sun came high and hot. Gral emerged from his sleep-place on the ledge, faint and hungry but knowing he must try yet again. He took a step, his feet tangled, and growling deep he reached down and tore at a tough twining substance.

Sinews. Sinews stripped bare by his own hunger, all that Otah and others had tossed him these past days; they were taut and clinging now, unresilient, like the vines of the young trees and yet strangely unlike.

Unlike! Gral stared, as his throat went pulsing. He reached out and touched; one had twined about a rock, was now so fast that his fingers could not cause it to move. For a long time he crouched, perplexed, growling deep as his fingers explored. He glanced up at the sun, and then back, and with that glance two things came together with searing shock....

For the very first time, man—a Pleistocene man—had made a clear cerebral distinction of cause and effect.

Gral arose. There was a wild new urgency. Quickly he searched and he found, across all the great ledge, sinews from the gorging which the sun had not yet touched. Some among the tribe stared with immobile contempt, thinking Gral the scavenger was yet hungry. But Gral gathered quickly, and departed, and was soon at the far place by the great bole, where he retrieved his stone and set feverishly to work.

Indeed it was not like the vines! It was easy now, but he was doubly thorough; he made his fingers be strong as he followed the pattern he knew so well. The sinews held, they held! His part done at last, he went out from the trees and placed his shaft where the sun's hot stroke