"Statistically, it must be recognized that no human action is without consequences to the man who acts. Again statistically, it must be recognized that the consequences of an action tend with strong probability to follow the general pattern of the action. A violent action, for example, has a strong probability of violent consequences, and since at least some of the consequences of an act must affect the person acting, a man who acts violently exposes himself to the probability that chance consequences which affect him, if unfavorable, will be violently so."
Probability and Human Conduct—Fitzgerald
Murgatroyd had been inoculated with a blood sample from the girl Helen some three hours or less before sunset. But it was one of the more valuable genetic qualities of the tormal race that they reacted to bacterial infection as a human being reacts to medication. Medicine on the skin of a human being rarely has any systemic effect. Medication on mucous membrane penetrates better. Ingested medication—medicine that is swallowed—has greater effectiveness still. But substances injected into tissues or the bloodstream have the most effect of all. A centigram of almost any drug administered by injection will have an effect close to that of a gram taken orally. It acts at once and there is no modification by gastric juices.
Murgatroyd had had half a cubic centimeter of the girl's blood injected into the spot on his flank where he could feel no pain. It contained the unknown cause of the plague on Maris III. Its effect as injected was incomparably greater than the same infective material smeared on his skin or swallowed. In either such case, of course, it would have had no effect at all, because tormals were to all intents and purposes immune to ordinary contagions. Just as they had a built-in unit in their digestive tract to cause the instant rejection of unwholesome food, their body cells had a built-in ability to produce antibodies immediately if the toxin of a pathogenic organism came into contact with them. So tormals were effectively safe against any disease transmitted by ordinary methods of infection. Yet if a culture of pathogenic bacteria, say, were injected into their bloodstream, their whole body was attacked, and all at once. There was practically no incubation period.
Murgatroyd, who had been given the plague in mid-afternoon, was reacting violently to its toxins by sunset. But two hours after darkness fell he arose and said shrilly, "Chee-chee-chee!" He'd been sunk in heavy slumber. When he woke, there was a small fire in the glade, about which the exhausted, emaciated fugitives consulted with Calhoun.
Calhoun was saying bitterly, "The whole thing is wrong! It's self-contradictory, and that means a man, or men, trying to meddle with the way the universe was made to run. Those characters in the city aren't fighting the plague—they're cooperating with it! When I came in a Med Ship, they should have welcomed my help. Instead they tried to kill me so I couldn't perform the function I was made for and trained for! They're going against the way the universe works. From what Helen tells me, they landed with the purpose of helping the plague wipe out everybody else on the planet. They began their butchery immediately. That's why you people ran away."
The weary, weakened people listened almost numbly.
"The invaders—and that's what they are," said Calhoun angrily, "have to be immune and know it, or else they wouldn't risk contagion by tracking you down to murder you. The city's infected and they're not alarmed. You're dying and they only try to hasten your death. I arrive, and I might be of use, so they try to kill me. They must know what the plague is and what it does, because their only criticism of it seems to be that it doesn't kill fast enough. And that is out of the ordinary course of nature. It's not intelligent human conduct."
Murgatroyd peered about. He'd just waked, and the look of his surroundings had changed entirely while he slept.
"A plague's not pleasant, but it's natural. This plague is neither pleasant nor natural. There's human interference with the normal course of events—certainly the way things are going is abnormal. I'm not too sure somebody didn't direct this from the beginning. That's why I shot that man with the crossbow instead of taking a blaster to him. I meant to wound him so I could make him answer questions, but the crossbow's not an accurate weapon and it happened that I killed him instead. There wasn't much information in the stuff in his pockets. The only significant item was a ground-car key, and that only means there's a car waiting for him to come back from hunting you."
The gaunt young man said drearily, "He didn't come from Dettra, which is our planet. Fashions are different on different worlds, and he wears a uniform we don't have. His clothing uses fasteners we don't use, too. He's from another solar system entirely."
Murgatroyd saw Calhoun and rushed to him. He embraced Calhoun's legs with enthusiasm. He chattered shrilly of his relief at finding the man he knew. The skeletonlike plague victims stared at him.
"This," said Calhoun with infinite relief, "is Murgatroyd. He's had the plague and is over it. So now we'll get you people cured. I wish I had better light!"
He counted Murgatroyd's breathing and listened to his heart. Murgatroyd was in that state of boisterous good health which is standard in any well-cared-for lower animal, but amounts to genius in a tormal. Calhoun regarded him with deep satisfaction.
"All right!" he said. "Come along!"
He plucked a brand of burning resinous stuff from the campfire. He handed it to the gaunt young man and led the way. Murgatroyd ambled complacently after him. Calhoun stopped under one of the unoccupied shelters and got out his lab kit. He bent over Murgatroyd. What he did, did not hurt. When he stood up, he squinted at the red fluid in the instrument he'd used.
"About twenty cc's," he observed. "This is strictly emergency stuff I'm doing now. But I'd say that there's an emergency."
The gaunt young man said, "I'd say you've doomed yourself. The incubation period seems to be about six days. It took that long to develop among the doctors we had on the office staff."
Calhoun opened a compartment of the kit, whose miniscule test tubes and pipettes gleamed in the torchlight. He absorbedly transferred the reddish fluid to a miniature filter-barrel, piercing a self-healing plastic cover to do so. He said, "You're a pre-med of course. The way you talk—"
"I was an intern," said Kim. "Now I'm pre-corpse."
"I doubt that last," said Calhoun. "But I wish I had some distilled water . . . this is anticoagulant." He added a trace of a drop to the sealed, ruddy fluid. He shook the whole filter to agitate it. The instrument was hardly bigger than his thumb. "Now a clumper . . ." He added a minute quantity of a second substance from an almost microscopic ampule. He shook the filter again. "You can guess what I'm doing. With a decent lab I'd get the structure and formula of the antibody Murgatroyd has so obligingly turned out for us. We'd set to work synthesizing it, and in twenty hours we would have it coming out of the reaction flasks in quantity. But there is no lab."
"There's one in the city," said the gaunt young man hopelessly. "It was for the colonists who were to come. And we were staffed to give them proper medical care. When the plague came, our doctors did everything imaginable. They not only tried the usual culture tricks, but they cultured samples of every separate tissue in fatal cases. They never found a single organism, even with electron microscopes, that would produce the plague." He said with a sort of weary pride, "Those who'd been exposed worked until they had the plague, and then others took over. Every man worked as long as he could make his brain serve him."
Calhoun squinted through the glass tube of the filter at the light of the sputtering torch.
"Almost clumped," he said. Then he added, "I suspect there's been some very fine laboratory work done somewhere to give the invaders their confidence of immunity to this plague. They landed and instantly set to work to mop up the city—to complete the job the plague hadn't quite finished. I suspect there could have been some fine lab work done to make plague mechanism undetectable. I don't like the things I'm forced to suspect!"
He inspected the glass filter again.
"Somebody," he said coldly, "considered that my arrival would be an unfavorable circumstance to him and what he wanted to happen. I think it is. He tried to kill me. He didn't. I'm afraid I consider his existence an unfavorable circumstance." He paused, and said very measuredly, "Cooperating with a plague is a highly technical business; it needs as much information as fighting a plague. Cooperation could no more be done from a distance than fighting it. If the invaders had come to fight the plague, they'd have sent their best medical men to help. If they came to assist it, they'd have sent butchers, but they'd also send the very best man they had to make sure that nothing went wrong with the plague itself. The logical man to be field director of the extermination project would be the man who'd worked out the plague himself." He paused again, and said icily, "I'm no judge to pass on anybody's guilt or innocence or fate, but as a Med Service man I've authority to take measures against health hazards!"
He began to press the plunger of the filter, judging by the wavering light of the torch. The piston was itself the filter, and on one side a clear, mobile liquid began very slowly to appear.
"Just to be sure, though—you said there was a lab in the city and the doctors found nothing."
"Nothing," agreed Kim hopelessly. "There'd been a complete bacteriological survey of the planet. Nothing new appeared. Everybody's oral and intestinal flora were normal. Naturally, no alien bug would be able to compete with the strains we humans have been living with for thousands of years. So there wasn't anything unknown in any culture from any patient."
"There could have been a mutation," said Calhoun. He watched the clear serum increase. "But if your doctors couldn't pass the disease—"
"They could!" said Kim bitterly. "A massive shot of assorted bugs would pass it, breathed or swallowed or smeared on the skin. Experimental animals could be given the plague. But no one organism could be traced as giving it. No pure culture would!"
Calhoun continued to watch the clear fluid develop on the delivery side of the filter piston. Presently there was better than twelve cubic centimeters of clear serum on one side, and an almost solid block of clumped blood cells on the other. He drew off the transparent fluid with a fine precision.
"We're working under far from aseptic conditions," he said wryly, "but we have to take the chances. Anyhow, I'm getting a hunch. A pathogenic mechanism that isn't a single, identifiable bug—it's not natural. It smells of the laboratory, just as uniformed murderers who are immune to a plague do. It's not too wild a guess to suspect that somebody worked out the plague as well as the immunization of the invaders. That it was especially designed to baffle the doctors who might try to fight it."
"It did," agreed Kim bitterly.
"So," said Calhoun, "maybe a pure culture wouldn't carry the plague. Maybe the disaster-producing apparatus simply isn't there when you make pure cultures. There's even a reason to suspect something specific. Murgatroyd was a very sick animal. I've only known of one previous case in which a tormal reacted as violently as Murgatroyd did to an injection. That case had us sweating."
"If I were going to live," said Kim grimly, "I might ask what it was."
"Since you're going to," Calhoun told him, "I'll tell you. It was a pair of organisms. Separately, they were so near harmless as makes no difference. Together, their toxins combined to be pure poison. It was synergy. They were a synergic pair which, together, were like high explosive. That one was the devil to track down!"
He went back across the glade. Murgatroyd came skipping after him, scratching at the anesthetic patch on his side.
"You go first," said Calhoun briefly to Helen Jons. "This is an antibody serum. You may itch afterward, but I doubt it. Your arm, please."
She bared her pitifully thin arm. He gave her practically a cc of fluid which—plus corpuscles and some forty-odd other essential substances—had been circulating in Murgatroyd's bloodstream not long since. The blood corpuscles had been clumped and removed by one compound plus the filter, and the anticoagulant had neatly modified most of the others. In a matter of minutes, the lab kit had prepared as usable a serum as any animal-using technique would produce. Logically, the antibodies it contained should be isolated and their chemical structure determined. They should be synthesized, and the synthetic antibody-complex administered to plague victims. But Calhoun faced a group of people doomed to die. He could only use his field kit to product a small-scale miracle for them. He could not do a mass-production job.
"Next!" said Calhoun. "Tell them what it's all about, Kim."
The gaunt young man bared his own arm. "If what he says is so, this will cure us. If it isn't so, nothing can do us any more harm."
And Calhoun briskly gave them, one after another, the shots of what ought to be a curative serum for an unidentified disease which he suspected was not caused by any single germ, but by a partnership. Synergy is an acting together. Charcoal will burn quietly. Liquid air will not burn at all. But the two together constitute a violent explosive. The ancient simple drug sulfa is not intoxicating. A glass of wine is not intoxicating. But the two together have the kick of dynamite. Synergy in medicine is a process by which, when one substance with one effect is given in combination with another substance with another effect, the two together have the consequences of a third substance intensified to fourth or fifth or tenth power.
"I think," said Calhoun when he'd finished, "that by morning you'll feel better—perhaps cured of the plague entirely and only weak from failure to force yourselves to take nourishment. If it turns out that way, then I advise you all to get as far away from the city as possible for a considerable while. I think this planet is going to be repopulated. I suspect that shiploads of colonists are on the way here now, but not from Dettra, which built the city. And I definitely guess that, sick or well, you're going to be in trouble if or when you contact the new colonists."
They looked tiredly at him. They were a singular lot of people. Each one seemed half-starved, yet their eyes had not the brightness of suffering. They looked weary beyond belief, and yet there was no self-neglect. They were of that singular human type which maintains human civilization against the inertia of the race, because it drives itself to get needed things done. It is not glamorous, this dogged part of mankind which keeps things going. It is sometimes absurd. For dying folk to wash themselves when even such exertion calls for enormous resolution is not exactly rational. To help each other to try to die with dignity was much more a matter of self-respect than of intellectual decision. But as a Med Ship man, Calhoun viewed them with some warmth. They were the type that has to be called on when an emergency occurs and the wealth-gathering type tends to flee and the low time-sense part of a population inclines to riot or loot or worse.
Now they waited listlessly for their own deaths.
"There's no exact precedent for what's happened here," explained Calhoun. "A thousand years or so ago there was a king of France—a country back on old Earth—who tried to wipe out a disease called leprosy by executing all the people who had it. But lepers were a nuisance. They couldn't work. They had to be fed by charity. They died in inconvenient places and only other lepers dared handled their bodies. They tended to throw normal human life out of kilter. That wasn't the case here. The man I killed wanted you dead for another reason. He and his friends wanted you dead right away."
The gaunt Kim Walpole said tiredly, "He wanted to dispose of our bodies in a sanitary fashion."
"Nonsense!" snapped Calhoun. "The city's infected. You lived, ate, breathed, walked in it. Nobody can dare use that city unless they know how the contagion's transmitted, and how to counteract it. Your own colonists turned back. These men wouldn't have landed if they hadn't known they were safe!"
There was silence.
"If the plague is an intended crime," added Calhoun, "you are the witnesses to it. You've got to be gotten rid of before colonists from somewhere other than Dettra arrive here."
The dark-bearded man growled, "Monstrous! Monstrous!"
"Agreed," said Calhoun. "But there's no interstellar government now, any more than there was a planetary government in the old days back on Earth. So if somebody pirates a colony ready to be occupied, there's no authority able to throw them out. The only recourse would be war. And nobody is going to start an interplanetary war—not with the bombs that can be landed! If the invaders can land a population here, they can keep the place." He paused, and said with irony, "Of course they could be persuaded that they were wrong."
But that was not even worth thinking about. In the computation of probabilities in human conduct, self-interest is a high-value factor. Children and barbarians have clear ideas of justice due to them, but no idea at all of justice due from them. And though human colonies spread toward the galaxy's rim, there was still a large part of every population which was civilized only in that it could use tools. Most people still remained comfortably barbaric or childish in their emotional lives. It was a fact that had to be considered in Calhoun's profession. It bore remarkably on matters of contagion, and health, and life itself.
"You'll have to hide. Perhaps permanently," he told them. "It depends partly on what happens to me, however. I have to go to the city. There's a very serious health problem there."
Kim said with irony, "In the city? Everybody's healthy there. They're so healthy that they come out to hunt us down for sport!"
"Considering that the city's thoroughly infected, their immunity is a health problem," said Calhoun. "But besides that, it looks like the original cause of the plague is there, too. I'd guess that the originator of this plague is technical director of the exterminating operation that's in progress on this planet. I'd guess he's in the ship that brought the butcher-invaders. I'd be willing to bet that he's got a very fine laboratory on the ship."
Kim stared at him. He clenched and unclenched his hands.
"And I'd say it ought to be quite useless to fight this plague before that man and that laboratory were taken care of," said Calhoun. "You people are probably all right. I think you'll wake up feeling better. You may be well. But if the plague is artificial, if it was developed to make a colony planet useless to the world that built it, but healthy for people who want to seize it . . ."
"What?"
"It may be the best plague that was developed for the purpose, but you can be sure it's not the only one. Dozens of strains of deadly bugs would have to be developed to be sure of getting the deadliest. Different kinds of concealment would have to be tried, in case somebody guessed the synergy trick, as I did, and could do something about the first plague used. There'd have to be a second and third and fourth plague available. You see?"
Kim nodded, speechless.
"A setup like that is a real health hazard," said Calhoun. "As a Med Service man, I have to deal with it. It's much more important than your life or mine or Murgatroyd's. So I have to go into the city to do what can be done. Meanwhile, you'd better lie down now. Give Murgatroyd's antibodies a chance to work."
Kim started to move away. Then he said, "You've been exposed. Have you protected yourself?"
"Give me a quarter-cc shot," said Calhoun. "That should do."
He handed the injector to the gaunt young man. He noted the deftness with which Kim handled it. Then he helped get the survivors of the original group—there were six of them now—to the leafy beds under the shelters. They were very quiet, even more quiet than their illness demanded. They were very polite. The old man and woman who'd struggled back to the glade together made a special effort to bid Calhoun good night with the courtesy appropriate to city folk of tradition.
Calhoun settled down to keep watch through the night. Murgatroyd snuggled confidingly close to him. There was silence.
But not complete silence. The night of Maris III was filled with tiny noises, and some not so faint. There were little squeaks which seemed to come from all directions, including overhead. There were chirpings which were definitely at ground level. There was a sound like effortful grunting in the direction of the hills. In the lowlands there was a rumbling which moved very slowly from one place to another. By its rate of motion, Calhoun guessed that a pack or herd of small animals was making a night journey and uttering deep-bass noises as it traveled.
He debated certain grim possibilities. The man he'd killed had had a ground-car key in his pocket. He'd probably come out in a powered vehicle. He might have had a companion, and the method of hunting down fugitives—successful, in his case—was probably well established. That companion might come looking for him, so watchfulness was necessary.
Meanwhile, there was the plague. The idea of synergy was still most plausible. Suppose the toxins—the poisonous metabolic products—of two separate kinds of bacteria combined to lessen the ability of the blood to carry oxygen and scavenge away carbon dioxide? It would be extremely difficult to identify the pair, and the symptoms would be accounted for. No pure culture of any organism to be found would give the plague. Each, by itself, would be harmless. Only a combination of the two would be injurious. And if so much was assumed, and the blood lost its capacity to carry oxygen, mental listlessness would be the first symptom of all. The brain requires a high oxygen level in its blood supply if it is to work properly. Let a man's brain be gradually, slowly, starved of oxygen and all the noted effects would follow. His other organs would slow down, but at a lesser rate. He would not remember to eat. His blood would still digest food and burn away its own fat—though more and more sluggishly, while his brain worked only foggily. He would become only semiconscious, and then there would come a time of coma when unconsciousness claimed him and his body lived on only as an idling machine, until it ran out of fuel and died.
Calhoun tried urgently to figure out a synergic combination which might make a man's blood cease to do its work. Perhaps only minute quantities of the dual poison might be needed. It might work as an antivitamin or an antienzyme, or—
The invaders of the city were immune, though. Quite possibly the same antibodies Murgatroyd had produced were responsible for their safety. Somewhere, somebody had very horribly used the science of medicine to commit a monstrous crime. But medicine was still a science. It was still a body of knowledge of natural law. And natural laws are consistent and work together toward that purpose for which the universe was made.
He heard a movement across the clearing. He reached for his blaster. Then he saw what the motion was. It was Kim Walpole, intolerably weary, trudging with infinite effort to where Helen Jons lay. Calhoun heard him ask heavily, "You're all right?"
"Yes, Kim," said the girl softly. "I couldn't sleep. I'm wondering if we can hope."
Kim didn't answer.
"If we live . . ." said the girl yearningly. She stopped.
Calhoun felt that he ought to put his fingers in his ears. The conversation was strictly private. But he needed to be on guard, so he coughed, to give notice that he heard. Kim called to him, "Calhoun?"
"Yes," said Calhoun. "If you two talk, I suggest that you do it in whispers. I'm going to watch in case the man I killed had a companion who might come looking for him. One question, though. If the plague is artificial, it had to be started. Did a ship land here two weeks or a month before your workmen began to be ill? It could have come from anywhere."
"There was no landing of any ship," said Kim. "No."
Calhoun frowned. His reasoning seemed airtight. The plague must have been introduced here from somewhere else!
"There had to be," he insisted. "Any kind of ship! From anywhere!"
"There wasn't," repeated Kim. "We had no off-planet communication for three months before the plague appeared. There's been no ship here at all except from Dettra, with supplies and workmen and that sort of thing."
Calhoun scowled. This was impossible. Then Helen's voice sounded very faintly. Kim made a murmurous response. Then he said, "Helen reminds me that there was a queer roll of thunder one night not long before the plague began. She's not sure it means anything, but in the middle of the night, with all the stars shining, thunder rolled back and forth across the sky above the city. This was a week or two before the plague. It waked everybody. Then it rolled away to the horizon and beyond. The weather people had no explanation for it."
Calhoun considered. Murgatroyd nestled still closer to him. He snapped his fingers suddenly.
"That was it!" he said savagely. "That's the trick! I haven't all the answers, but I know some very fine questions to ask now. And I think I know where to ask them."
He settled back. Murgatroyd slept. There was the faintest possible murmur of voices where Kim Walpole and the girl Helen talked wistfully of the possibility of hope.
Calhoun contemplated the problem before him. There were very, very few survivors of the people who belonged in the city. There was a shipload of murderers—butchers!—who had landed to see that the last of them were destroyed. Undoubtedly there was a highly trained and probably brilliant microbiologist in the invaders' expedition. One would be needed, to make sure of the success of the plague and to verify the absolute protection of the butchers, so that other colonists could come here to take over and use the planet. There could be no failure of protection for the people not of Dettra who expected to inhabit this world. There would have to be completely competent supervision of this almost unthinkable, this monstrous stealing of a world.
"The plague would probably be a virus pair," muttered Calhoun. "Probably introduced and scattered by a ship with wings and rockets. It'd have wings because it wouldn't want to land, but did want to sweep back and forth over the city. It'd drop frozen pellets of the double virus culture. They'd drop down toward the ground, melting and evaporating as they fell, and they'd flow over the city as an invisible, descending blanket of contagion coating everything. Then the ship would head away over the horizon and out to space on its rockets. Its wings wouldn't matter out of atmosphere and it'd go into overdrive and go back home to wait . . ."
He felt an icy anger, more savage than any rage could be. With this technique, a confederation of human beings utterly without pity could become parasitic on other worlds. They could take over any world by destroying its people, and no other people could make any effective protest, because the stolen world would be useless except to the murderers who had taken it over. This affair on Maris III might be merely a test of the new ruthlessness. The murderer planet could spread its ghastly culture like a cancer through the galaxy.
But there were two other things involved beside a practice of conquest through murder by artificial plagues. One was what would happen to the people—the ordinary, commonplace citizens—of a civilization which spread and subsisted by such means. It would not be good for them. In the aggregate, they'd be worse off than the people who died.
The other?
"They might make a field test of their system," said Calhoun very coldly, "without doing anything more serious to the Med Service than killing one man—me—and destroying one small Med Ship. But they couldn't adopt this system on any sort of scale without destroying the Med Service first. I'm beginning to dislike this business excessively!"