But Leithgow's answer was abstracted. Four minutes for Carse to come! Or else, everything lost! He busied himself helping the four surgeons and two of his own assistants into the white, sterilized gowns, and the masks that left only the eyes free and the skin-tight rubber gloves, but his mind was not with his actions. The old man looked very frail now; his age showed in the deep lines now eminent on his face. Three minutes--swiftly two.... "At least," observed Ku Sui, "we have one body ... the coolie. I had better start immediately on him." "Bring him out," Leithgow instructed one of his men. "One brain will be saved. But--_there!_ Thank God! Hear that? Coming down the passage? It's Carse, returning!" * * * * * It was Carse. He and Ban Wilson, coming down the passage from the top of the tree-shaft. Everyone in the laboratory could hear plainly the heavy, sliding tread of the great space-boots. Eliot Leithgow was first to the door. He opened it, peered through eagerly and called: "Carse? You've got them?" "Yes, Eliot. Here--we need help." The Hawk's voice sounded weary. Friday and the scientist ran down the passageway until they reached the adventurer. In the faint light, they saw he was carrying a limp body. He laid it carefully down on the floor. "Ban's coming down with another," he said, "and there are two more above. Go up and get them, Friday." The Negro started to obey. But Eliot Leithgow did not move, did not utter a sound. He stood staring at the body Carse had laid down. The parchmentlike skin of his face seemed to whiten; that was all; but he winced and slowly brushed his eyes with his hands when, in a moment, Ban Wilson floated down the shaft and, approached with a second unconscious body. At last Leithgow whispered: "They're all--like that, Carse?" "Yes," answered the emotionless voice. "There were two others, but we let them go. They were worse." The gray eyes looked steadily at Eliot Leithgow. "I know," the Hawk said. "It's horrible--but it can't be helped. It was these or nothing. There was no choice." Hawk Carse had fulfilled his promise. He had brought back four isuanacs. CHAPTER XI _Ordeal_ Five bodies lay on the operating tables in Eliot Leithgow's laboratory. The air, hushed and heavy, was pervaded by the various odors of antiseptics and etheloid. The breathing cones had been applied to each of the bodies, and they were now locked fast in controlled unconsciousness. On the first table lay the body of the robot-coolie, a man of medium size, sturdy, well-muscled, with the smooth round yellow face and stub nose of his kind. His short-cropped, bristly black hair had been shaved off; the head was now bald. That head was destined to hold the mighty brain of Master Scientist Raymond Cram.