Shiela spoke from beside Don, "Perhaps he's one that they hadn't treated with the rays and forgot about in their hurry to leave," she suggested. "Probably," he agreed, and turned to the roboe. "That's all right," he informed the roboe. With pain in his heart he looked once more at the scrupulously clean cylindrical tanks, the various valves that regulated every minute detail of heat and nourishment to the protoplasm within. The least deviation would result in either stunted and unsatisfactory growth or kill the growing cells. Without looking at either the waiting roboe or Shiela, he directed, "Set the master temperature control to 120 degrees." There was a gasp from Shiela and a slight hesitation before the roboe's protest, "But sir, that will kill all the growths!" "And one hundred lives," accused the girl. "Those are Doctor Stone's orders; I realize the consequences but it must be done. It could conceivably mean more than one hundred human lives if the new roboes were to be allowed to develop." He kept his eyes down at the toes of his shoes. "I'm afraid that I must refuse, sir," the roboe replied. Angered by the position with which he felt sympathy, Don retorted, "All right, then step back and I'll...." His voice trailed off at the sight of the needle gun held by the roboe, pointed directly at him. The hithertofore pleasant features of the roboe, common to all of them, were now set in harsh lines. [Illustration: A needle gun, held by the roboe, pointed directly at Don. The hithertofore pleasing features of the roboe, common to all of them, were now set in harsh lines.] Astonished, Don blurted, "But you ... then ... you must be a rebel roboe." He took another step forward, "Put that down and do as I told you, or leave!" * * * * * The reflexes originally built into the mechanical but living creature caused the gun to waver slightly, then steady as living and thinking reflexes overcame the mechanical ones. There was pain in the roboe's eyes as he warned, "I'll be forced to kill you, sir. Reinforcements will arrive soon to complete the creation of the new roboes, then we'll depart. But no harm must come to the protoplasm for the present." Don looked from the roboe to Shiela, who stood to one side, trembling. "Get out of my way," he ordered roughly, turning to the master control panel. Out of the corner of an eye he saw the needle gun come to the level of the roboe's eyes and he instinctively stiffened himself for the shock of the needle that would result in the paralysis of his heart muscles and a quick death. There might be time to reach the control panel and damage it sufficiently to kill the protoplasm. There was a loud explosion and he fell almost to his knees before recovering. The roboe, he saw to his astonishment, had a big hole blown in his chest and the colorless life-fluid gushed out, before the roboe sank to his knees. The needle gun had fallen out of reach.