"Very much of physical science is merely the comprehension of long-observed facts. In human conduct there is a long tradition of observation, but a very brief record of comprehension. For example, human lives in contact with other human lives follow the rules of other ecological systems. All too often, however, a man imagines that an ecological system is composed only of things, whereas such a system operates through the actions of things. It is not possible for any part of an ecological complex to act upon the other parts without being acted upon in its turn. So that it follows that it is singularly stupid—but amazingly common—for an individual to assume human society to be passive and unreactive. He may assume that he can do what he pleases, but inevitably there is a reaction as energetic as his action, and as well-directed. Moreover, probability . . ."
Probability and Human Conduct—Fitzgerald
An hour after sunrise Calhoun's shoulder pack was empty of food. The refugees arose, and they were weak and ravenous. Their respiration had slowed to normal. Their pulses no longer pounded. Their eyes were no longer dull, but very bright. But they were in advanced states of malnutrition, and now were aware of it. Their brains were again receiving adequate oxygen and their metabolism was at normal level—and they knew they were starving.
Calhoun served as cook. He trudged to the spring that Helen described. He brought back water. While they sucked on sweet tablets from his rations and watched with hungry eyes, he made soup from the dehydrated rations he'd carried for Murgatroyd and himself. He gave it to them as the first thing their stomachs were likely to digest.
He watched as they fed themselves. The elderly man and woman sipped delicately, looking at each other. The man with the broad dark beard ate with tremendous self-restraint. Helen fed the weakest, oldest man, between spoonsful for herself, and Kim Walpole ate slowly, brooding.
Calhoun kept them going, slowly providing them with food, until he had no more to offer. By then they had made highly satisfying gains in strength. But it was then late morning.
He drew Kim aside.
"During the night," he said, "I got another lot of serum ready. I'm leaving it with you, with an injector. You'll find other fugitives. I gave you massive doses. You'd better be stingy. Try half-cc shots. Maybe you can skimp that."
"What about you?" demanded Kim.
Calhoun shrugged.
"I've got an awful lot of authority, if I can make it stick," he said dryly. "As a Med Ship man I've power to take complete charge of any health emergency. You people have a plague here. That's one emergency. It's artificial. That's another. The people who've spread it here have reason, in their success to date on this planet, to think they can take over any other world they choose. And, human nature being what it is, that's the biggest health hazard in history. I've got to get to work on it."
"There's a shipload of armed murderers here," said Kim.
"I'm not much interested in them," admitted Calhoun. "I want to get at the man who's at the head of this thing. As I told you, he should have other plagues in stock. It's entirely possible that the operation here is no more than a small-scale field test of a new technique for conquest."
"If those butchers find you, you'll be killed."
"True," admitted Calhoun. "But the number of chance happenings that could favor me is much greater than the number that could favor them. I'm working with nature, and they're working against it. Anyhow, as a Med Service man, I should prevent the landing of anybody—anybody at all—on a plague-stricken planet like this. And I suspect there are plans for landings. I should set up an effective quarantine."
His tone was dry. Kim Walpole stared. "You mean you'll try to stop them?"
"I shall try," said Calhoun, "to implement the authority vested in me by the Med Service for such cases as this. The rules about quarantine are rather strict."
"You'll be killed," said Kim again.
Calhoun ignored the repeated prediction.
"That invader found you," he observed, "because he knew that you'd have to drink. So he found a brook and followed it up, looking for signs of humans drinking from it. He found footprints about the spring. I found his footprints there, too. That's the trick you'll use to find other fugitives. But pass on the word not to leave tracks hereafter. For the other advice, I advise you to get all the weapons you can. Modern ones, of course. You've got the blaster from the man I killed."
"I think," said Kim between his teeth, "that I'll get some more. If hunters from the city do track us to our drinking places, I'll know how to get more weapons!"
"Yes," agreed Calhoun. "Now. Murgatroyd made the antibodies that cured you. As a general rule, you can expect antibody production in your own bodies once an infection begins to be licked. In case of extreme emergency, each of you can probably supply antibodies for a fair number of other plague victims. You might try serum from blisters you produce on your skin. Quite often antibodies turn up there. I don't guarantee it, but sometimes it works."
He paused. Kim Walpole said harshly, "But you! Isn't there anything we can do for you?"
"I was going to ask you something," said Calhoun. He produced the telephoto films of the city as photographed from space. "There's a laboratory in the city. A biochemistry lab. Show me where to look for it."
Walpole gave explicit directions, pointing out the spot on the photo. Calhoun nodded. Then Kim said fiercely, "But tell us something we can do! We'll be strong, presently, and we'll have weapons. We'll track downstream to where hunters leave their ground-cars and be equipped with them. We can help you!"
Calhoun nodded approvingly.
"Right. If you see the smoke of a good-sized fire in the city, and if you've got a fair number of fairly strong men with you, and if you've got ground-cars, you might investigate. But be cagey about it. Very cagey!"
"If you signal we'll come," said Kim Walpole grimly, "no matter how few we are."
"Fine," said Calhoun. He had no intention of calling on these weakened, starving people for help.
He swung his depleted pack on his back again and slipped away from the glade. He made his way to the spring, which flowed up clear and cool from unseen depths. He headed down the little brook which flowed away from it. Murgatroyd raced along its banks. He hated to get his paws wet. Presently, where the underbrush grew thickly close to the water's edge, Murgatroyd wailed, "Chee! Chee!" Calhoun plucked him from the ground and set him on his shoulder. Murgatroyd clung blissfully there as Calhoun followed down the stream bed. He adored being carried.
Two miles down, there was another cultivated field. This one was planted with an outsized root crop, and Calhoun walked past shoulder-high bushes with four-inch blue-and-white flowers. He recognized the plant as one of the family Solanaceae—belladonna was still used in medicine—but he couldn't identify it until he dug up a root and found a tuber. But the six-pound specimen he uncovered was still too young and green to be eaten. Murgatroyd refused to touch it.
Calhoun was ruefully considering the limitations of specialized training when he came to the end of the cultivated field. There was a highway. It was new, of course. City, fields, highways, and all the physical aspects of civilized life had been built on this planet before the arrival of the colonists who were to inhabit it. It was extraordinary to see such preparations for a population not yet on hand. But Calhoun was much more interested in the ground-car he found waiting on the highway, hard by a tiny bridge under which a small brook flowed.
The key he'd taken from the dead invader fitted. He got in the car and beckoned Murgatroyd to the seat beside him.
"Characters like the man I killed, Murgatroyd," he observed, "aren't very important. They're mere butchers—killers. That sort of character likes to loot. There's nothing here for them to loot. They're bound to be bored. They're bound to be restless. We won't have much trouble with them. I'm worrying about the man who possibly designed and is certainly supervising the action of the plague. I look for trouble with him."
The ground-car was in motion then, toward the city. He drove on.
It was a good twenty miles, but he did not encounter a single other vehicle. Presently the city lay spread out before him. He surveyed it thoughtfully. It was very beautiful. Fifty generations of architects on many worlds had played with stone and steel, groping for perfection. This city was a close approach. There were towers which glittered whitely, and low buildings which seemed to nestle on the vegetation-covered ground. There were soaring bridges and gracefully curving highways, and park areas laid out and ready. There was no monotony anywhere.
The only exception to gracefulness was the massive landing grid, half a mile high and a mile across, which was a lacework of monster steel girders with spider-thin wires of copper woven about them in the complex curves its operation required. Inside it, Calhoun could see the ship of the invaders. It had landed in the grid enclosure, and later Calhoun had blown out the transformers of the grid. They were probably in process of repair now. But the ship stood sturdily on the ground inside the great structure which dwarfed it.
"The man we're after will be in that ship, Murgatroyd," said Calhoun. "He'll have inner and outer lock-doors fastened, and he'll be inside a six-inch beryllium-steel wall. Rather difficult to break in upon. And he'll be uneasy. An intellectual type gone wrong doesn't feel at ease with the kind of butchers he has to associate with. I think the problem is to get him to invite us into his parlor. But it may not be simple."
"Chee," said Murgatroyd doubtfully.
"Oh, we'll manage," Calhoun assured him. "Somehow!"
He spread out his photographs. Kim Walpole had marked where he should go and a route to it. Having been in the city while it was being built, he knew even the service lanes which, being sunken, were not a part of the city's good looks.
"But the invaders," explained Calhoun, "won't deign to use grubby service lanes. They consider themselves aristocrats because they were sent to be conquerors, though the work required of them was simple butchery. I wonder what sort of swine run the world they came from!"
He put away the photos and headed for the city again. He branched off the main highway, near the city. A turn-off descended into a cut. The road in the cut was intended for loads of agricultural produce entering the city. It was strictly utilitarian. It ran below the surface of the park areas, and entered the city without pride. When among the buildings it ran between rows of undecorated gates, behind which waste matter was destined to be collected to be carted away as fertilizer for the fields. The city was very well designed.
Rolling through the echoing sunken road, Calhoun saw, just once, a ground-car in motion on a far-flung, cobwebby bridge between two tall towers. It was high overhead. Nobody in it would be watching grubby commerce roads.
The whole affair was very simple indeed. Calhoun brought the car to a stop beneath the overhang of a balconied building many stories high. He got out and opened the gate. He drove the car into the cavernous, so-far-unused lower part of the building. He closed the gate behind him. He was in the center of the city, and his presence was unknown. This was at three or later in the afternoon.
He climbed a clean new flight of steps and came to the sections the public would use. There were glassy walls which changed their look as one moved between them. There were the lifts. Calhoun did not try to use them. He led Murgatroyd up the circular ramps which led upward in case of unthinkable emergency. He and Murgatroyd plodded up and up. Calhoun kept count.
On the fifth level there were signs of use, while all the others had that dusty cleanness of a structure which has been completed but not yet occupied.
"Here we are," said Calhoun cheerfully.
But he had his blaster in his hand when he opened the door of the laboratory. It was empty. He looked approvingly about as he hunted for the storeroom. It was a perfectly equipped biological laboratory, and it had been in use. Here the few doomed physicians awaiting the city's population had worked desperately against the plague. Calhoun saw the trays of cultures they'd made, dried up and dead now. Somebody had turned over a chair. Probably when the laboratory was searched by the invaders, in case someone not of their kind still remained alive in it.
He found the storeroom. Murgatroyd watched with bright eyes as he rummaged.
"Here we have the things men use to cure each other," said Calhoun oracularly. "Practically every one a poison save for its special use! Here's an assortment of spores—pathogenic organisms, Murgatroyd. They have their uses. And here are drugs which are synthesized nowadays, but are descended from the poisons found on the spears of savages. Great helps in medicine. And here are the anesthetics—poisons too. These are what I am counting on."
He chose, very painstakingly. Dextrethyl. Polysulfate. The one marked inflammable and dangerous. The other with the maximum permissible dose on its label, and the names of counteracting substances which would neutralize it. He burdened himself. Murgatroyd reached up a paw. Since Calhoun was carrying something, he wanted to carry something, too.
They went down the circular ramp again as sunset drew near. Calhoun searched once more in the below-surface levels of the buildings. He found what he wanted—a painter's vortex-gun which would throw "smoke rings" of tiny paint droplets at a wall or object to be painted. One could vary the size of the ring at impact from a bare inch to a three-foot spread.
Calhoun cleaned the paint-gun. He was meticulous about it. He filled its tank with dextrethyl brought down from the laboratory. He piled the empty containers out of sight.
"This trick," he observed, as he picked up the paint-gun again, "was devised to be used on a poor devil of a lunatic who carried a bomb in his pocket for protection against imaginary assassins. It would have devastated a quarter-mile circle, so he had to be handled gently."
He patted his pockets. He nodded.
"Now we go hunting—with an oversized atomizer loaded with dextrethyl. I've polysulfate and an injector to secure each specimen I knock over. Not too good, eh? But if I have to use a blaster I'll have failed."
He looked out a window at the sky. It was now late dusk. He went back to the gate to the service road. He went out and carefully closed it behind him. On foot, with many references to the photomaps, he began to find his way toward the landing grid. It ought to be something like the center of the invaders' location.
It was dark when he climbed other service stairs from the cellar of another building. This was the communications building of the city. It had been the key to the mopping-up process the invaders began on landing. Its callboard would show which apartments had communicators in use. When such a call showed, a murder party could be sent to take care of the caller. Even after the first night, some individual, isolated folk might remain, unaware of what was happening. So there would be somebody on watch, just in case a dying man called for the solace of a human voice while still he lived.
There was a man on watch. Calhoun saw a lighted room. Paint-gun ready, he moved very silently toward it. Murgatroyd padded faithfully behind him.
Outside the door, Calhoun adjusted his curious weapon. He entered. The man nodded in a chair before the lifeless board. When Calhoun entered he raised his head and yawned. He turned.
Calhoun sprayed him with smoke rings—vortex rings. But the rings were spinning missiles of vaporized dextrethyl, that anesthetic developed from ethyl chloride some two hundred years before, and not yet bettered for its special uses. One of its properties was that the faintest whiff of its vapor produced a reflex to gasp. A second property was that, like the ancient ethyl chloride, it was the quickest-acting anesthetic known.
The man by the callboard saw Calhoun. His nostrils caught the odor of dextrethyl. He gasped.
He fell unconscious.
Calhoun waited patiently until the dextrethyl was out of the way. It was almost unique among vapors in that at room temperature it was lighter than air. It rose toward the ceiling. Presently Calhoun moved forward and brought out the polysulfate injector. He bent over the unconscious man. He did not touch him otherwise.
He turned and walked out of the room with Murgatroyd piously marching behind him.
Outside, Calhoun said, "As one medical man to another, perhaps I shouldn't have done that. But I'm dealing with a health hazard, a plague. Sometimes one has to use psychology to supplement standard measures. I consider that the case here. Anyhow this man should be missed sooner than most. He has a job where his failure to act should be noticed."
"Chee?" asked Murgatroyd zestfully.
"No," said Calhoun. "He won't die. He wouldn't be so unkind."
It was dark outdoors now. When Calhoun stepped out into the street—he'd touched nothing in the callboard office to show that he'd entered it—nightfall was complete. Stars shone brightly, but the empty, unlighted ways of the city were black. There seemed to be a formless menace in the air. When Calhoun moved down the street, Murgatroyd, who hated the dark, reached up a furry paw and held on to Calhoun's hand for reassurance.
Calhoun moved silently and Murgatroyd's footfalls were inaudible. The feel of the never-lived-in city was appalling. A sleeping city seems ghostly and strange, even with lighted streets. An abandoned city is intolerably desolate, with all its inhabitants gone or dead. But a city which has never lived, which lies lifeless under a night sky because its people never came to occupy it—that city has the worst feeling of all. It seems unnatural. It seems insane. It is like a corpse which could have lived but never acquired a soul, and now waits horribly for something demoniac to enter it and give it a seeming of life too horrifying to imagine.
The invaders unquestionably felt that creeping atmosphere of horror. Presently there was proof. Calhoun heard small, drunken noises in the street. He tracked them cautiously. He found the place—one lighted ground-floor window on a long street lined on both sides with towering structures reaching for the sky. The sheer walls were utterly dark. The narrow lane of stars that could be seen overhead seemed utterly remote. The street itself was empty and dark, and murmurous with echoes of sounds that had not ever really been made. And here there were no natural sounds at all. Building walls cut off the normal night-sounds of the open country. There was a dead and muffled and murmurous stillness fit to crack one's eardrums.
Except for the drunken singing. Men drank together in an unnecessarily small room, which they had lighted very brightly to try to make it seem alive. All about them was deadness and stillness, so they made supposedly festive noises, priming themselves to cheerfulness with many bottles. With enough to drink, perhaps the illusion could be believed in. But it was a pitifully tiny thread of sound in a dark and empty city. Outside, where Calhoun and Murgatroyd paused to listen, the noise of drunken singing had a quality of biting irony.
Calhoun grunted, and the sound echoed endlessly between the stark walls around and above.
"We could use those characters," he said coldly, "only there are too many of them."
He and Murgatroyd went on. He'd familiarized himself with the stars, earlier, and knew that he moved in the direction of the landing grid. He'd arranged for one man on duty—at the callboard—to fail to do his work. The process was carefully chosen. He'd knocked out the invader with vortex rings of dextrethyl vapor, and then had given him a shot of polysulphate. The combination was standard, like magnesium sulphate and ether, centuries before. Polysulphate was an assisting anesthetic, never used alone because a man who was knocked out by it stayed out for days. In surgery it was used in a quantity which seemed not to affect a man at all, yet the least whiff of dextrethyl would then put him under for an operation, while he could instantly be revived. It was safer and under better control than any other kind of anesthesia.
But Calhoun had reversed the process. He'd put the callboard operator under with vapor, and then given polysulphate to keep him under for sixty hours or more. And then he'd left him. When the invader was found unconscious, it would bother the other butchers very much. They'd never suspect his condition to be the result of enemy action. They'd consider him in a coma. A coma was the last effect of the plague that had presented them with a planet. They'd believe their fellow to be dying of the plague they were supposed to be immune to. They would panic, expecting immediate death for themselves. But more than one man in a comalike state would be more effective in producing complete disorganization and despair.
A door banged, back by the lighted window in the desolate black street. Someone came out. Someone else. A third man. They moved along the street, singing hoarsely and untunefully and with words as slurred and uncertain as their footsteps. Echoes resounded between the high building walls. The effect was eerie.
Calhoun moved into a doorway. He waited. When the three men were opposite him, they linked arms to steady themselves. One man roared out quite unprintable verses of a song in which another joined uncertainly from time to time. The third protested aggrievedly. He halted, and the three of them argued solemnly about something indefinable, swaying as they talked with owlish, drunken gravity.
Calhoun lifted the paint-gun. He held down the trigger. Invisible rings of dextrethyl vapor whisked toward the trio. They gasped. They collapsed. Calhoun took his measures.
Presently one man lay unconscious on the street in a coma which imitated perfectly, except for the emaciation, the terminal coma of the fugitives from the city. Some distance away Calhoun plodded on toward the landing grid with a second man, also unconscious, over his shoulder. Murgatroyd followed closely. The third man, stripped to his underwear, waited where he might be found within the next day or two.