Nordenfeld drank half his drink and said unpleasantly, "There were thirty million people on Kamerun when the chlorophage appeared. At first it was apparently a virus which fed on the chlorophyll of plants. They died. Then it was discovered that it could also feed on hemoglobin, which is chemically close to chlorophyll. Hemoglobin is the red coloring matter of the blood. When the virus consumed it, people began to die. Kamerun doctors found that the chlorophage virus was transmitted by contact, by inhalation, by ingestion. It traveled as dust particles and on the feet of insects, and it was in drinking water and the air one breathed. The doctors on Kamerun warned spaceships off and the Patrol put a quarantine fleet in orbit around it to keep anybody from leaving. And nobody left. And everybody died. _And_ so did every living thing that had chlorophyll in its leaves or hemoglobin in its blood, or that needed plant or animal tissues to feed on. There's not a person left alive on Kamerun, nor an animal or bird or insect, nor a fish nor a tree, or plant or weed or blade of grass. There's no longer a quarantine fleet there. Nobody'll go there and there's nobody left to leave. But there are beacon satellites to record any calls and to warn any fool against landing. If the chlorophage got loose and was carried about by spaceships, it could kill the other forty billion humans in the galaxy, together with every green plant or animal with hemoglobin in its blood." "That," said Jensen, and tried to smile, "sounds final." "It isn't," Nordenfeld told him. "If there's something in the universe which can kill every living thing except its maker, that something should be killed. There should be research going on about the chlorophage. It would be deadly dangerous work, but it should be done. A quarantine won't stop contagion. It can only hinder it. That's useful, but not enough." Jensen moistened his lips. Nordenfeld said abruptly, "I've answered your questions. Now what's on your mind and what has it to do with chlorophage?" Jensen started. He went very pale. "It's too late to do anything about it," said Nordenfeld. "It's probably nonsense anyhow. But what is it?" Jensen stammered out his story. It explained why there were so many passengers for the _Star Queen_. It even explained his departure from Altaira. But it was only a rumor--the kind of rumor that starts up untraceably and can never be verified. This one was officially denied by the Altairan planetary government. But it was widely believed by the sort of people who usually were well-informed. Those who could sent their families up to the _Star Queen_. And that was why Jensen had been tense and worried until the liner had actually left Altaira behind. Then he felt safe. Nordenfeld's jaw set as Jensen told his tale. He made no comment, but when Jensen was through he nodded and went away, leaving his drink unfinished. Jensen couldn't see his face; it was hard as granite.