Johnny took off one of his metal-soled shoes and started hammering the fine glass as if something whipped him into a frantic effort to escape. Dorothy silent beside him, Norman watched the black-haired boy rub his eyes wearily as he pounded with the shoe. How had Sade gotten this picture? What was his purpose in showing it now? The glass of Johnny's prison must have been superbly invisible but soft for slowly he ground a shallow niche at the base of the wall, a foothold. Norman felt like yelling a cheer but he whispered an oath as he watched Johnny grind out a higher foothold. Trying to carve a niche higher still, his fingers stained the glass red. Quickly the glass was dripping with blood. "Look at his hands!" Dorothy whispered. In Johnny's efforts to cling to the wall, the ground glass was eating away the tips of his fingers. And Norman shuddered to see the gray change creeping over Johnny's face. Before his eyes, Johnny's dark hair became streaked with gray and his ashen face became furrowed with wrinkles. Horror-ridden years, swiftly heaped upon him. Dorothy covered her face with her hands. But Norman couldn't tear his eyes from the luminous screen. The film had been cut to speed it up. Johnny had hacked five slits in the glass now. His fingers and thumbs were ragged stumps as he hung on the splintered glass, ten feet up the blood-smeared wall. And in his terrible fascination, Norman saw that Johnny's hands healed almost as fast as they were torn. As the dry flesh of age withered his face, as he sacrificed his hands in a mad struggle to escape the invisible terror in Vulcan's sunlight. Norman slammed his fists against the locked door. "Sade! You scum of the universe!" But there was no answer as his eyes were drawn back to the screen to see Johnny's fingerless paws grasp the rim of his prison. A wrinkled, animal-like thing, eyes yellowed and wild, he drew up his gnarled legs and fell over the glass wall into the gravel on the other side. Half crawling, half running, he disappeared quickly into the trees. As though a prolonged roar of sound had suddenly ceased, the panel darkened, leaving only Dorothy's muffled sobs. But in Norman's brain was a numb hate that froze his reason. He didn't hear the door open behind him. "Interesting, wasn't it?" It was Sade's voice. "But in a moment an even more interesting experiment will take place in my laboratory." Norman turned slowly. Swart and the two patrolmen stood with the fat man at the door. Norman took one quick step forward. His right hand shot out. His fingers sank like spikes into the flabby skin of Sade's throat. Another split second and Norman's fingers would have met behind the Mercurian's windpipe and ripped it out, but in that split second the patrolmen were on him. Then he was on the floor, fighting silently in the blackness of his fury. A heavy boot caught him behind the left ear and the blackness engulfed him completely. III