"I suppose you're right," he muttered. It had set him thinking. Was he losing his manhood? The human race didn't have so much need for expansion any more. Only greed and craving for adventure would set a man exploring now. And he had neither. Or had he? He thought of the daydreams he sometimes had--of roaming through the primitive jungles of Venus, searching perhaps for a trace of a near human, intelligent civilization, blasting his way through hordes of threatening monsters. But all that was silly; he was a trained man, and it would be very foolish to risk such a brain as his in that hotbed of violence. Still, what good was that precious brain doing anyone at Interplanetary? The shortage of radium prevented their going ahead with the program of experiments which Dr. Theller had mapped out. The idea of wasting their dwindling supply in a roundabout process of learning what the Martians could so easily tell them, had turned the staff of the Institute into a pack of frustrated malcontents. * * * * * The Earth easily supported its population of ten billion. Masterpieces of engineering had irrigated and made fertile practically all of the Earth's surface, except around the poles. There was no need to grow crops, anyway, other than that fresh natural foods were more palatable. Enough food for a hundred billion people could be manufactured synthetically from the sun's rays. There was no need, say, for colonizing Venus, but such a project would certainly provide an outlet for the energies of a bored young scientist. Art still sulked as they returned to the laboratory, but the idea had been planted in his mind, and the more he thought, the nearer he came to admitting that Elene was right. Little did he dream that he would soon be so busy that looking for thrills would be the least of his worries. A white faced attendant met them at the front door of the laboratory. "Dr. Douglas! That thing--we can't control it--it's--" Art ran to the room where he had left the creature. The granite block was where he had left it, but had a neat round hole in its top. Then he looked at the opposite wall of the room. It was a crumbling ruin. The wormlike animal had evidently wriggled its way to the plastocrete wall where it had started boring. As the wall was only five or six inches thick, it had kept emerging from one side or another, dropping to the floor, and starting all over again. The attendants, not knowing how to pick it up, had left it alone after suffering several gashes. They were afraid to handle it too roughly, for fear of damaging it. Art smiled grimly at this. He picked the thing up, threw it on the table. He decided that he would dissect the specimen here and now, find the secret of its mighty strength. But at that moment Dr. Theller came in. "Well, Art, I hope you've thoroughly familiarized yourself with that creature because--"