None watched more tensely than Connant. A little sterile gla.s.s test tube, half filled with straw-colored fluid. One*two*three*four*five drops of the clear solution Dr. Copper had prepared from the drops of blood from Connant's arm. The tube was shaken carefully, then set in a beaker of clear, warm water. The thermometer read blood heat, a little thermostat clicked noisily, and the electric hotplate began to glow as the lights flickered slightly. Then*little white flecks of precipitation were forming, snowing down in the clear straw-colored fluid. "Lord," said Connant. He dropped heavily into a bunk, crying like a baby. "Six days*" Connant sobbed, "six days in there*wondering if that d.a.m.ned test would lie*"

Garry moved over silently, and slipped his arm across the physicist's back.

"It couldn't lie," Dr. Copper said. "The dog was human-immune*and the serum reacted."

"He's*all right?" Norris gasped. "Then*the animal is dead*dead forever?"

"He is human," Copper spoke definitely, "and the animal is dead."

Kinner burst out laughing, laughing hysterically. McReady turned toward him and slapped his face with a methodical one-two, one-two action. The cook laughed, gulped, cried a moment, and sat up rubbing his cheeks, mumbling his thanks vaguely. "I was scared. Lord, I was scared*"

Norris laughed brittlely. "You think we weren't, you ape? You think maybe Connant wasn't?"

The Ad Building stirred with a sudden rejuvenation. Voices laughed, the men cl.u.s.tering around Connant spoke with unnecessarily loud voices, jittery, nervous voices relievedly friendly again. Somebody called out a suggestion, and a dozen started for their skis. Blair, Blair might recover* Dr. Copper fussed with his test tubes in nervous relief, trying solutions. The party of relief for Blair's shack started out the door, skis clapping noisily. Down the corridor, the dogs set up a quick yelping howl as the air of excited relief reached them.

Dr. Copper fussed with his tubes. McReady noticed him first, sitting on the edge of the bunk, with two precipitin-whitened test tubes of straw-colored fluid, his face whiter than the stuff in the tubes, silent tears slipping down from horror-widened eyes.

McReady felt a cold knife of fear pierce through his heart and freeze in his breast. Dr. Copper looked up. "Garry," he called hoa.r.s.ely. "Garry, for G.o.d's sake, come here."

Commander Garry walked toward him sharply. Silence clapped down on the Ad Building. Connant looked up, rose stiffly from his seat.

"Garry*tissue from the monster*precipitates, too. It proves nothing. Nothing*but the dog was monster-immune too. That one of the two contributing blood*one of us two, you and I, Garry*one of us is a monster."

X.

"Bar, call back those men before they tell Blair," McReady said quietly. Barclay went to the door; faintly his shouts came back to the tensely silent men in the room. Then he was back.

"They're coming," he said. "I didn't tell them why. Just that Dr. Copper said not to go."

"McReady," Garry sighed, "you're in command now. May G.o.d help you. I cannot."

The bronzed giant nodded slowly, his deep eyes on Commander Garry.

"I may be the one," Garry added. "I know I'm not, but I cannot prove it to you in any way. Dr. Copper's test has broken down. The fact that he showed it was useless, when it was to the advantage of the monster to have that uselessness not known, would seem to prove he was human."

Copper rocked back and forth slowly on the bunk. "I know I'm human. I can't prove it either. One of us two is a liar, for that test cannot lie, and it says one of us is. I gave proof that the test was wrong, which seems to prove I'm human, and now Garry has given that argument which proves me human*which he, as the monster, should not do. Round and round and round and round and*"

Dr. Copper's head, then his neck and shoulders began circling slowly in time to the words. Suddenly he was lying back on the bunk, roaring with laughter. "It doesn't have to prove one of us is a monster! It doesn't have to prove that at all! Ho-ho. If we're all monsters it works the same*we're all monsters*all of us*Connant and Garry and I*and all of you."

"McReady," Van Wall, the blond-bearded Chief Pilot, called softly, "you were on the way to an M.D. when you took up meteorology, weren't you? Can you make some kind of test?"

McReady went over to Copper slowly, took the hypodermic from his hand, and washed it carefully in ninety-five percent alcohol. Garry sat on the bunk edge with wooden face, watching Copper and McReady expressionlessly. "What Copper said is possible," McReady sighed. "Van, will you help me here? Thanks." The filled needle jabbed into Copper's thigh. The man's laughter did not stop, but slowly faded into sobs, then sound sleep as the morphia took hold.

McReady turned again. The men who had started for Blair stood at the far end of the room, skis dripping snow, their faces as white as their skis. Connant had a lighted cigarette in each hand; one he was puffing absently, and staring at the floor. The heat of the one in his left hand attracted him and he stared at it and the one in the other hand stupidly for a moment. He dropped one and crushed it under his heel slowly.

"Dr. Copper," McReady repeated, "could be right. I know I'm human*but of course can't prove it. I'll repeat the test for my own information. Any of you others who wish may do the same."

Two minutes later, McReady held a test tube with white precipitin settling slowly from straw-colored serum. "It reacts to human blood too, so they aren't both monsters."

"I didn't think they were," Van Wall sighed. "That wouldn't suit the monster either; we could have destroyed them if we knew. Why hasn't the monster destroyed us, do you suppose? It seems to be loose."

McReady snorted. Then laughed softly. "Elementary, my dear Watson. The monster wants to have life-forms available. It cannot animate a dead body, apparently. It is just waiting*waiting until the best opportunities come. We who remain human, it is holding in reserve."

Kinner shuddered violently. "Hey. Hey, Mac. Mac, would I know if I was a monster? Would I know if the monster had already got me? Oh Lord, I may be a monster already."

"You'd know," McReady answered.

"But we wouldn't," Norris laughed shortly, half hysterically.

McReady looked at the vial of serum remaining. "There's one thing this d.a.m.ned stuff is good for, at that," he said thoughtfully. "Clark, will you and Van help me? The rest of the gang better stick together here. Keep an eye on each other," he said bitterly. "See that you don't get into mischief, shall we say?"

McReady started down the tunnel toward Dogtown, with Clark and Van Wall behind him. "You need more serum?" Clark asked.

McReady shook his head. "Tests. There's four cows and a bull, and nearly seventy dogs down there. This stuff reacts only to human blood and*monsters."

XI.

McReady came back to the Ad Building and went silently to the wash stand. Clark and Van Wall joined him a moment later. Clark's lips had developed a tic, jerking into sudden, unexpected sneers.

"What did you do?" Connant exploded suddenly. "More immunizing?"

Clark snickered, and stopped with a hiccough. "Immunizing. Haw! Immune all right."

"That monster," said Van Wall steadily, "is quite logical. Our immune dog was quite all right, and we drew a little more serum for the tests. But we won't make any more."

"Can't*can't you use one man's blood on another dog*" Norris began.

"There aren't," said McReady softly, "any more dogs. Nor cattle, I might add."

"No more dogs?" Benning sat down slowly.

"They're very nasty when they start changing," Van Wall said precisely. "But slow. That electrocution iron you made up, Barclay, is very fast. There is only one dog left*our immune. The monster left that for us, so we could play with our little test. The rest*" He shrugged and dried his hands.

"The cattle*" gulped Kinner.

"Also. Reacted very nicely. They look funny as h.e.l.l when they start melting. The beast hasn't any quick escape, when it's tied in dog chains, or halters, and it had to be to imitate."

Kinner stood up slowly. His eyes darted around the room, and came to rest horribly quivering on a tin bucket in the galley. Slowly, step by step, he retreated toward the door, his mouth opening and closing silently, like a fish out of water.

"The milk*" he gasped. "I milked 'em an hour ago*" His voice broke into a scream as he dived through the door. He was out on the ice cap without windproof or heavy clothing.

Van Wall looked after him for a moment thoughtfully. "He's probably hopelessly mad," he said at length, "but he might be a monster escaping. He hasn't skis. Take a blow torch*in case."

The physical motion of the chased helped them; something that needed doing. Three of the men were quietly being sick. Norris was lying flat on his back, his face greenish, looking steadily at the bottom of the bunk above him.

"Mac, how long have the*cows been not-cows*"

McReady shrugged his shoulders hopelessly. He went over to the milk bucket, and with his little tube of serum set to work on it. The milk clouded it, making certainty difficult. Finally he dropped the test tube in the stand, and shook his head. "It tests negatively. Which means either they were cows then, or that, being perfect imitations, they gave perfectly good milk."

Copper stirred restlessly in his sleep and gave a gurgling cross between a snore and a laugh. Silent eyes fastened on him. "Would morphia*a monster*" somebody started to ask.

"Lord knows," McReady shrugged. "It affects every Earthly animal I know of."

Connant suddenly raised his head. "Mac! The dogs must have swallowed pieces of the monster, and the pieces destroyed them! The dogs were where the monster resided. I was locked up. Doesn't that prove*"

Van Wall shook his head. "Sorry. Proves nothing about what you are, only proves what you didn't do."

"It doesn't do that," McReady sighed. "We are helpless because we don't know enough, and so jittery we don't think straight. Locked up! Ever watch a white corpuscle of the blood go through the wall of a blood vessel? No? It sticks out a pseudopod. And there it is*on the far side of the wall."

"Oh," said Van Wall unhappily. "The cattle tried to melt down, didn't they? They could have melted down*become just a thread of stuff and leaked under a door to re-collect on the other side. Ropes*no*no, that wouldn't do it. They couldn't live in a sealed tank or*"

"If," said McReady, "you shoot it through the heart, and it doesn't die, it's a monster. That's the best test I can think of, offhand."

"No dogs," said Garry quietly, "and no cattle. It has to imitate men now. And locking up doesn't do any good. Your test might work, Mac, but I'm afraid it would be hard on the men."

XII.

Clark looked up from the galley stove as Van Wall, Barclay, McReady, and Benning came in, brushing the drift from their clothes. The other men jammed into the Ad Building continued studiously to do as they were doing, playing chess, poker, reading. Ralsen was fixing a sledge on the table; Vane and Norris had their heads together over magnetic data, while Harvey read tables in a low voice.

Dr. Copper snored softly on the bunk. Garry was working with Dutton over a sheaf of radio messages on the corner of Dutton's bunk and a small fraction of the radio table. Connant was using most of the table for cosmic ray sheets.

Quite plainly through the corridor, despite two closed doors, they could hear Kinner's voice. Clark banged a kettle onto the galley stove and beckoned McReady silently. The meteorologist went over to him.

"I don't mind the cooking so d.a.m.n much," Clark said nervously, "but isn't there some way to stop that bird? We all agreed that it would be safe to move him into Cosmos House."

"Kinner?" McReady nodded toward the door. "I'm afraid not. I can dope him, I suppose, but we don't have an unlimited supply of morphia, and he's not in danger of losing his mind. Just hysterical."

"Well, we're in danger of losing ours. You've been out for an hour and a half. That's been going on steadily ever since, and it was going for two hours before. There's a limit, you know."

Garry wandered over slowly, apologetically. For an instant, McReady caught the feral spark of fear*horror*in Clark's eyes, and knew at the same instant it was in his own. Garry*Garry or Copper*was certainly a monster.

"If you could stop that, I think it would be a sound policy, Mac," Garry spoke quietly. "There are*tensions enough in this room. We agreed that it would be safe for Kinner in there, because everyone else in camp is under constant eyeing." Garry shivered slightly. "And try, try in G.o.d's name, to find some test that will work." McReady sighed. "Watched or unwatched, everyone's tense. Blair's jammed the trap so it won't open now. Says he's got food enough, and keeps screaming 'Go away, go away*you're monsters. I won't be absorbed. I won't. I'll tell men when they come. Go away.' So*we went away."

"There's no other test?" Garry pleaded.

McReady shrugged his shoulders. "Copper was perfectly right. The serum test could be absolutely definitive if it hadn't been*contaminated. But that's the only dog left, and he's fixed now."

"Chemicals? Chemical tests?"

McReady shook his head. "Our chemistry isn't that good. I tried the microscope you know."

Garry nodded. "Monster-dog and real dog were identical. But*you've got to go on. What are you going to do after dinner?"

Van Wall had joined them quietly. "Rotation sleeping. Half the crowd sleep; half stay awake. I wonder how many of us are monsters? All the dogs were. We thought we were safe, but somehow it got Copper*or you." Van Wall's eyes flashed uneasily. "It may have gotten every one of you*all of you but myself may be wondering, looking. No, that's not possible. You'd just spring then, I'd be helpless. We humans must somehow have the greater numbers now. But*" he stopped.

McReady laughed shortly. "You're doing what Norris complained of in me. Leaving it hanging. 'But if one more is changed*that may shift the balance of power.' It doesn't fight. I don't think it ever fights. It must be a peaceable thing, in its own*inimitable*way. It never had to, because it always gained its end otherwise."

Van Wall's mouth twisted in a sickly grin. "You're suggesting then, that perhaps it already has the greater numbers, but is just waiting*waiting, all of them*all of you, for all I know*waiting till I, the last human, drop my wariness in sleep. Mac, did you notice their eyes, all looking at us."

Garry sighed. "You haven't been sitting here for four straight hours, while all their eyes silently weighed the information that one of us two, Copper or I, is a monster certainly*perhaps both of us."

Clark repeated his request. "Will you stop that bird's noise? He's driving me nuts. Make him tone down, anyway."

"Still praying?" McReady asked.

"Still praying," Clark groaned. "He hasn't stopped for a second. I don't mind his praying if it relieves him, but he yells, he sings psalms and hymns and shouts prayers. He thinks G.o.d can't hear well way down here."

"Maybe he can't," Barclay grunted. "Or he'd have done something about this thing loosed from h.e.l.l."

"Somebody's going to try that test you mentioned, if you don't stop him," Clark stated grimly. "I think a cleaver in the head would be as positive a test as a bullet in the heart."

"Go ahead with the food. I'll see what I can do. There may be something in the cabinets." McReady moved wearily toward the corner Copper had used as his dispensary. Three tall cabinets of rough boards, two locked, were the repositories of the camp's medical supplies. Twelve years ago, McReady had graduated, had started for an internship, and been diverted to meteorology. Copper was a picked man, a man who knew his profession thoroughly and modernly. More than half the drugs available were totally unfamiliar to McReady; many of the others he had forgotten. There was no huge medical library here, no series of journals available to learn the things he had forgotten, the elementary, simple things to Copper, things that did not merit inclusion in the small library he had been forced to content himself with. Books are heavy, and every ounce of supplies had been freighted in by air.

McReady picked a barbiturate hopefully. Barclay and Van Wall went with him. One man never went anywhere alone in Big Magnet.

Ralsen had his sledge put away, and the physicists had moved off the table, the poker game broken up when they got back. Clark was putting out the food. The clicks of spoons and the m.u.f.fled sounds of eating were the only sign of life in the room. There were no words spoken as the three returned; simply all eyes focused on them questioningly while the jaws moved methodically.

McReady stiffened suddenly. Kinner was screeching out a hymn in a hoa.r.s.e, cracked voice. He looked wearily at Van Wall with a twisted grin and shook his head. "Uh-uh."

Van Wall cursed bitterly, and sat down at the table. "We'll just plumb have to take that till his voice wears out. He can't yell like that forever."

"He's got a bra.s.s throat and a cast-iron larynx," Norris declared savagely. "Then we could be hopeful, and suggest he's one of our friends. In that case he could go on renewing his throat till doomsday."

Silence clamped down. For twenty minutes they ate without a word. Then Connant jumped up with an angry violence. "You sit as still as a bunch of graven images. You don't say a word, but oh, Lord, what expressive eyes you've got. They roll around like a bunch of gla.s.s marbles spilling down a table. They wink and blink and stare*and whisper things. Can you guys look somewhere else for a change, please?

"Listen, Mac, you're in charge here. Let's run movies for the rest of the night. We've been saving those reels to make 'em last. Last for what? Who is it's going to see those last reels, eh? Let's see 'em while we can, and look at something other than each other."

"Sound idea, Connant. I, for one, am quite willing to change this in any way I can."

"Turn the sound up loud, Dutton. Maybe you can drown out the hymns," Clark suggested.

"But don't," Norris said softly, "turn off the lights altogether."

"The lights will be out." McReady shook his head. "We'll show all the cartoon movies we have. You won't mind seeing the old cartoons will you?"

"Goody, goody*a moom-pitcher show. I'm just in the mood." McReady turned to look at the speaker, a lean, lanky New Englander, by the name of Caldwell. Caldwell was stuffing his pipe slowly, a sour eye c.o.c.ked up to McReady.