"We'll take the necessary measures," Nordenfeld told him. "Very quietly and very efficiently, with neither the crew nor the passengers knowing that Altaira sent the chlorophage on board the _Star Queen_ in the hope of banishing it from there. The passengers won't know that their own officials shipped it off with them as they tried to run away.... And I was so proud that I'd improvised an aseptic room to keep Kathy in! I sterilized the air that went in to her, and I sterilized--" Then he stopped. He stopped quite short. He stared at the air unit, set up and with two pipes passing through the plastic partition which cut the hospital space in two. He turned utterly white. He went roughly to the air machine. He jerked back its cover. He put his hand inside. Minutes later he faced back to the vision-screen from which Jensen looked apathetically at him. "Tell the skipper to call me," he said in a savage tone. "Tell him to call me instantly he comes back! Before he issues any orders at all!" He bent over the sterilizing equipment and very carefully began to disassemble it. He had it completely apart when Kathy waked. She peered at him through the plastic separation sheet. "Good morning, Doctor Nordenfeld," she said cheerfully. The doctor grunted. Kathy smiled at him. She had gotten on very good terms with the doctor, since she'd been kept in the ship's hospital. She did not feel that she was isolated. In having the doctor where she could talk to him at any time, she had much more company than ever before. She had read her entire picture book to him and discussed her doll at length. She took it for granted that when he did not answer or frowned that he was simply busy. But he was company because she could see him. Doctor Nordenfeld put the air apparatus together with an extremely peculiar expression on his face. It had been built for Kathy's special isolation by a ship's mechanic. It should sterilize the used air going into Kathy's part of the compartment, and it should sterilize the used air pushed out by the supplied fresh air. The hospital itself was an independent sealed unit, with its own chemical air freshener, and it had been divided into two. The air freshener was where Doctor Nordenfeld could attend to it, and the sterilizer pump simply shared the freshening with Kathy. But-- But the pipe that pumped air to Kathy was brown and discolored from having been used for sterilizing, and the pipe that brought air back was not. It was cold. It had never been heated.