One by one the lift-ships hooked onto the airlock of the _Star Queen_ and delivered passengers and cargo to the ship. Presently the last of them was hooked on, and the last batch of passengers came through to the liner, and the ship's doctor watched them stream past him. His air was negligent, but he was actually impatient. Like most doctors, Nordenfeld approved of lean children and wiry women. They had fewer things wrong with them and they responded better to treatment. Well, he was the doctor of the _Star Queen_ and he had much authority. He'd exerted it back on Regulus to insist that a shipment of botanical specimens for Cassim travel in quarantine--to be exact, in the ship's practically unused hospital compartment--and he was prepared to exercise authority over the passengers. He had a sheaf of health slips from the examiners on the ground below. There was one slip for each passenger. It certified that so-and-so had been examined and could safely be admitted to the _Star Queen's_ air, her four restaurants, her two swimming pools, her recreation areas and the six levels of passenger cabins the ship contained. He impatiently watched the people go by. Health slips or no health slips, he looked them over. A characteristic gait or a typical complexion tint, or even a certain lack of hair luster, could tell him things that ground physicians might miss. In such a case the passenger would go back down again. It was not desirable to have deaths on a liner in space. Of course nobody was ever refused passage because of chlorophage. If it were ever discovered, the discovery would already be too late. But the health regulations for space travel were very, very strict. He looked twice at a young woman as she passed. Despite applied complexion, there was a trace of waxiness in her skin. Nordenfeld had never actually seen a case of chlorophage. No doctor alive ever had. The best authorities were those who'd been in Patrol ships during the quarantine of Kamerun when chlorophage was loose on that planet. They'd seen beamed-up pictures of patients, but not patients themselves. The Patrol ships stayed in orbit while the planet died. Most doctors, and Nordenfeld was among them, had only seen pictures of the screens which showed the patients. * * * * * He looked sharply at the young woman. Then he glanced at her hands. They were normal. The young woman went on, unaware that for the fraction of an instant there had been the possibility of the landing of the _Star Queen_ on Altaira, and the destruction of her space drive, and the establishment of a quarantine which, if justified, would mean that nobody could ever leave Altaira again, but must wait there to die. Which would not be a long wait. A fat man puffed past. The gravity on Altaira was some five per cent under ship-normal and he felt the difference at once. But the veins at his temples were ungorged. Nordenfeld let him go by.