It was able to hide from men, which was something no other microorganism could accomplish. It was an ability that would offer no advantage to a disease germ in a state of purely natural happenings. Disease germs do not encounter bacteriological laboratories, as a rule, often enough to need to adapt to escape them. It would not help an average germ or microbe to be invisible to an electron microscope. There would be no reason for such invisibility to be developed.
But more than that, why should anybody want to keep a Med Service man like Calhoun from investigating a plague? When infected people fled from the city to die in the wilds, why should people remaining in the city try to destroy a Med Ship which might help to end the deaths? Ordinarily, well people in the middle of an epidemic are terrified lest they catch it. They'd be as anxious for Med Service help as those already infected. What was going on here?
"You said about a thousand people were in the city," observed Calhoun. "They tended the crops and waited for the city's permanent inhabitants. What happened after the plague was recognized to be one?"
"The first shipload of emigrants came from Dettra Two," said the girl hopelessly. "We didn't bring them to ground with the landing grid. Instead, we described the plague. We warned them away. We quarantined ourselves while our doctors tried to fight the disease. The shipload of new people went back to Dettra without landing."
Calhoun nodded. This would be normal.
"Then another ship came. There were maybe two hundred of us left alive. More than half of us already showed signs of the plague. This other ship came. It landed on emergency rockets because we had nobody left who knew how to work the grid."
Then her voice wavered a little as she told of the landing of the strange ship in the landing grid of the city that was dying without ever having really lived. There was no crowd to meet the ship. Those people who were not yet stricken had abandoned the city and scattered themselves widely, hoping to escape contagion by isolating themselves in new and uncontaminated dwelling units. But there was no lack of communication facilities. Nearly all the survivors watched the ship come down through vision screens in the control building of the then-useless grid.
The ship touched ground. Men came out. They did not look like doctors. They did not act like them. The vision screens in the control building were snapped off immediately. Contact could not be restored. So the isolated groups spoke agitatedly to each other by vision screen. They exchanged messages of desperate hope. Then, newly landed men appeared at an apartment whose occupant was in the act of such a conversation with a group in a distant building. He left the visiphone on as he went to admit and greet the men he hoped were researchers, at least, come to find the cause of the plague and end it.
The viewers at the other visiphone plate gazed eagerly into his apartment. They saw the group of newcomers enter. They saw them deliberately murder their friend and the survivors of his family.
Plague-stricken or merely terrified people—in pairs or trios widely separated through the city—communicated in swift desperation. It was possible that there had been a mistake, a blunder, and an unauthorized crime had been committed. But it was not a mistake. Unthinkable as such an idea was, there developed proof that the plague on Maris III was to be ended as if it were an epizootic among animals. Those who had it and those who had been exposed to it were to be killed to prevent its spread among the newcomers.
A conviction of such horror could not be accepted without absolute proof. But when night fell, the public power supply of the city was cut off and communications ended. The singular sunset hush of Maris III left utter stillness everywhere—except for the screams which echoed among the city's innumerable empty-eyed, unoccupied buildings.
The scant remainder of the plague survivors fled in the night. They fled singly and in groups, carrying the plague with them. Some carried members of their families who were too weak to walk. Others helped already-doomed wives or friends or husbands to the open country. Flight would not save their lives. It would only prevent their murder. But somehow that seemed a thing to be attempted.
"This," said Calhoun, "is not a history of your own case. When did you develop the disease, whatever it may be?"
"Don't you know what it is?" asked Helen hopelessly.
"Not yet," admitted Calhoun. "I've very little information. I'm trying to get more."
He did not mention the information gathered from a dead man in a corn field some miles away.
The girl told of her own case. The first symptom was listlessness. She could pull out of it by making an effort, but it progressed. Day by day more urgent, more violent effort was needed to pay attention to anything, and she noted greater weakness when she tried to act. She felt no discomfort, not even hunger or thirst. She'd had to summon increasing resolution even to become aware of the need to do anything at all.
The symptoms were singularly like those of a man too long at too high an altitude without oxygen. They were even more like those of a man in a non-pressurized flier, whose oxygen supply was cut off. Such a man would pass out without realizing that he was slipping into unconsciousness, only it would happen in minutes. Here the process was infinitely gradual. It was a matter of weeks. But it was the same thing.
"I'd been infected before we ran away," said Helen drearily. "I didn't know it then. Now I know I've a few more days of being able to think and act, if I try hard enough. But it'll be less and less each day. Then I'll stop being able to try."
Calhoun watched the tiny recorder roll its multiple-channel tape from one spool to the other as she talked.
"You had energy enough to try to kill me," he observed.
He looked at the weapon. There was an arched steel spring placed crosswise at the end of a barrel like a sporting blast-gun. Now he saw a handle and a ratchet by which the spring was brought to tension, storing up power to throw the missile. He asked, "Who wound up this crossbow?"
Helen hesitated. "Kim—Kim Walpole," she said finally.
"You're not a solitary refugee now? There are others of your group still alive?"
She hesitated again, and then said, "Some of us came to realize that staying apart didn't matter. We couldn't hope to live anyhow. We already had the plague. Kim is one of us. He's the strongest. He wound up the crossbow for me. He had the weapons to begin with."
Calhoun asked seemingly casual questions. She told him of a group of fugitives remaining together because all were already doomed. There had been eleven of them. Two were dead now. Three others were in the last lethargy. It was impossible to feed them. They were dying. The strongest was Kim Walpole, who'd ventured back into the city to bring out weapons for the rest. He'd led them, and now was still the strongest and—so the girl considered—the wisest of them all.
They were waiting to die. But the newcomers to the planet—the invaders, they believed—were not content to let them wait. Groups of hunters came out of the city and searched for them.
"Probably," said the girl dispassionately, "to burn our bodies against contagion. They kill us so they won't have to wait. And it just seemed so horrible that we felt we ought to defend our right to die naturally. That's why I shot at you. I shouldn't have, but . . ."
She stopped helplessly. Calhoun nodded.
The fugitives now aided each other simply to avoid murder. They gathered together exhaustedly at nightfall, and those who were strongest did what they could for the others. By day, those who could walk scattered to separate hiding places, so that if one was discovered, the others might still escape the indignity of being butchered. They had no stronger motive than that. They were merely trying to die with dignity, instead of being killed as sick beasts. Which bespoke a tradition and an attitude that Calhoun approved. People like these would know something of the science of probability in human conduct. Only they would call it ethics. But the strangers—the invaders—were of another type. They probably came from another world.