Still smiling, Sade glanced at Norman's troubled gaze, then shut off the hose, stuck it back in the cylinder and drew out another. The spray that dampened the rat this time was light pink. The rat's coarse coat thickened, its sides swelled before Norman's eyes and youth was born anew in the little animal's very brain as it leaped to its feet and scurried around the shelf with all the energy of fresh strength. "It's like many poisons," Sade said. "Full strength, its effect is death. Greatly diluted--with mere water--its miracles make it an elixir supreme...." The door opened to Keren, followed by Dorothy and Swart. Keren's poise little hinted she'd plotted Sade's death less than an hour ago. Dorothy had removed her space suit; her eyes were red from crying. Keren took a cigarette from her loose blouse. "You sent for me, Sade?" The Mercurian's eyes were like a rattlesnake's as he held out his two hands for her to see. "I have these now," he said softly. "Soon I shall have every world at my command. Will you marry me?" The dark-haired woman lit her cigarette calmly, her hand steady. "Yes," she answered simply. Sade laughed. "You say yes now because your life is at stake--because you tried to aid the Earthman. But for that you won't lose your life, Keren. You will lose something you value more than your life, Keren. You will lose--your beauty. Get a rope, Swart." Keren flicked her cigarette into Sade's face. Quick as a whip, her hand entered the throat of her blouse. Norman saw the glint of naked metal flash in an arc toward Sade's chest. Dorothy gasped. [Illustration: _Keren whirled and lunged at the screaming Mercurian._] The silver dagger sank into Sade's chest just over his heart. The fat man staggered back. But before he could fall, Swart acted, as quick as a ferret, clipped Keren's chin, and as she crumpled silently to the floor, he caught the gasping Mercurian and eased him down. From Sade's chest blood spurted higher than the dagger's hilt as Swart yanked one of the hoses from the cylinder and directed its crimson spray on Sade's wound. Slowly, Swart drew out the dagger's sticky blade in the spray. When the dagger was out of Sade's chest there was no visible sign of a wound. Sade opened his eyes and looked up at them. "What shall I do with her?" Swart said. Sade got to his feet. He stood there, panting a moment. "The rope," he said. Swart pushed a wall button, extracted a length of cord from a panel compartment and returned. "Tie her to the cylinder," Sade hissed, "and tie the nozzle of the hose in her hair." In a moment, the unconscious Keren was hanging by her backward-bent arms from the cylinder. The cord was tight from her wrists, around the cylinder and under to her slim ankles. In her hair was fixed the slowly oozing hose. A rivulet of red trickled down her smooth cheek. "What about these two?" Swart said, motioning toward Norman and Dorothy.