Carl studied the man carefully, watching the rise and fall of his breathing. The man WAS breathing--breathing the lethal gases that should kill him in thirty seconds. "You find it hard to believe, don't you?" Edgerton said suddenly. Carl nodded. "I have a nephew who collects stamps," he heard himself saying. "He has one with your picture on it. It's a rarity now, 'cause it's almost forty years old, but the picture on the stamp looks just like you--just like you do NOW!" "How is it done Mr. Edgerton?" Diane asked pointedly. "Why is it that you can breathe this air when it kills everyone else?" Edgerton's eyes narrowed when he heard the voice. Then he leaned over and peered into the mud-stained face-plate. He smiled. "I'll be damned," he said. "A woman. A real live woman! Pretty too." "How is it done?" Diane persisted. Edgerton's grin faded. He turned to Carl. "You mean you don't know?" Carl eyed the man, his lips set in an aggravating silence. Then: "Yes, I know. Or at least I think I know. Furthermore, Dr. Hamlin knows too. He's known all the time. Obviously, this girl is the only one who's still in the dark. I think it's about time someone told her." "Wait!" Dr. Hamlin said. "Say, what's this all about?" Edgerton said suddenly. "Where's Paul Spero anyhow? Rhind and Mitchell are waiting!" Carl flicked a look at Diane, then turned back to her father. "Are you going to tell her? Or should I?" "Tell me what?" Diane said. "How does he know about Paul Spero? Spero told us...." V "Spero told us a lot of things," Carl said thickly. "He told us he'd taken pictures without speaking to anyone. It served his purpose better to keep us in the dark about how this immortality thing was really worked until after we got here. After that, he figured he'd take over and we'd have to go along with him whether we liked it or not. Furthermore, Ferguson and your father were in on it from the beginning, weren't you?" "Please," Dr. Hamlin said nervously, "it's not near as bad as you're making it out to be. It's only a minor adjustment." "Minor adjustment!" Carl grasped the arm of Diane's jumper, pulling her along with him through the long corridors of boxes. At the far end of the structure, he found what he was searching for. Three boxes--slitted in front like a zoo cage. And inside the boxes, peering at them through sad yellow-rimmed eyes--were three chowls. "There's the answer to your immortality," Carl said grimly. "Rhind and Mitchell were both doctors--surgeons. Do you get it now?" Raymond Edgerton and Norman Hamlin had joined them now. "Mr. Keating," Edgerton said, "I'm sure if you were a doctor, you wouldn't be so squeamish about a thing like this. After all, what's a simple operation?" "Simple operation!"