could not bear the thought of not being able to peer out into the night.

The room buzzed with a kind of orderly confusion. The men were scared and they made no effort to conceal it. Gallifa studied a slip of paper covered with tally marks, and then quickly stuffed it into his pocket.

Ten men were now missing, not counting the ones already in the hospital. They couldn't be accounted for, so it had to be assumed they were either sick—or dead.

It had been decided that Gallifa and Dr. Thorndyke were the best qualified to take charge of the camp, until normality returned. Gallifa studied the men carefully.

"We haven't much to go on," he said with grim candor. "We're still in the dark as to what is happening. We only know that when it takes place, it happens damn fast—and without discrimination. Men have been affected both in and out of camp.

"So far, here are the facts. To the best of our knowledge none of the men have been bitten by animals and we haven't found any poisonous plants. Dr. Thorndyke is considering the possibility that some unknown virus which affects the brain may be responsible. He's over in the laboratory running tests now. If it is a virus, grouping together like this might be a mistake. We'll load everybody up with antibiotics and hope for the best. We've got to lick this!"

"Until now," Gallifa continued grimly, "no one has been hurt except the stricken men. We want to keep it that way. One fact stands out bluntly. All of the men have been damned anti-social. They want to be left alone, and will attempt to kill anyone who gets close to them. That should make them easy to spot. If we are to have a chance to cure them, we have to catch them first."

"We are going to have to consider the likelihood that more of us will be affected. We must do everything within our power to isolate those suspiciously-acting persons. Probably the ship Mac and I discovered didn't have the warning I am giving to you now. We can lick this thing if we're determined enough. The main thing is not to lose your head. Watch your neighbor, but don't jump to conclusions. Be sure before you act."

There was a stir and Gallifa paused. The doctor pushed his way through the men to the front of the room. His face was white and haggard.

"What about the tests?" Gallifa asked.

"There aren't going to be any tests," Dr. Thorndyke replied grimly. "At least not on the men in the hospital. They are all dead."

"What happened?" Gallifa urged, his eyes wide with shock.

Everyone was very quiet.

The doctor wiped his hand across his forehead. "Nolan was on duty in the wardroom. He went out for a smoke. I heard him go out. I didn't hear him come back. I was setting up some new equipment. When I finally went back to the ward Nolan must have caught—whatever it is. He was gone, and he'd slit every man's throat with a scalpel."

Gallifa faced the assemblage. "We're going to inoculate everyone here. As soon as we're through, I want each team to go to their own shacks and stay there. If you have to go somewhere, go in pairs. If you see anyone wandering around by himself, no matter who he is, bang him over the head with something and bring him over to the hospital. Otherwise, stay put."

The men received their shots in an uncomfortable silence and disappeared into the night. Gallifa, MacFarland, and Dr. Thorndyke remained in the Administration room.

"Any idea what it is, doc?" MacFarland asked huskily.

"I hardly had time to take care of the patients," Dr. Thorndyke replied bitterly. "Did you honestly expect me to find out what was wrong with them in a few short hours?"

"But—" Gallifa began.

MacFarland suddenly started, and leapt to his feet. The doctor moved away, his face paling.

"What's the matter?" Gallifa asked, alarmed.

"Don't be so old womanish," MacFarland snapped. "I'm not catching it. I just thought of something. Cummings had a gun. Where did he get it?"

"The storeroom!" Gallifa exclaimed. "I'd forgotten we had weapons and ammo in the storeroom! If things got bad enough, we could wipe ourselves out. We'd better check."

"I'm going back to the hospital," Dr. Thorndyke said bluntly. "I'm going to lock the door. If anyone comes banging around he damn well had better know who he is and talk intelligently—or I'll slice him from his wishbone to his crotch." He stalked out.

Gallifa stared blankly after Dr. Thorndyke. It was funny hearing him talk this way. He had always thought of the doc as being rather mild-mannered. Damned flexible, humans!

VI

They found the door was torn off the storeroom. It hadn't even been secured. Someone had just been in a terrific hurry. There wasn't a single weapon left. MacFarland studied the disarray, then thoughtfully hefted a broad-bladed pick axe.

"I'm of the opinion," he said quietly, "that in a short time things are going to get a little rough around here."

"Now wait a minute, Mac," Gallifa protested.

"Sorry, boy," MacFarland said grimly. "If I knew everyone else was barehanded, I would go along with you. I may not be the next victim—or the tenth. I'll more than likely have to protect myself against someone who has come down with it, however, and I've got an overwhelming desire to stay alive."

Gallifa let his hands drop helplessly to his sides. MacFarland was right, of course. They hadn't acted soon enough. Was this how panic was born?

"Mac," Gallifa tried huskily. "We've got to keep our heads. If we don't, we'll destroy ourselves."

"I'm open to any suggestions," MacFarland said steadily. "But until I'm satisfied that the danger is past, I'll just hang on to this axe."

"Let's go back over to the hospital," Gallifa said wearily. "We'll use Thorndyke's projector and go over every inch of micro-film we have. We may be too close to the problem. There must be something we've overlooked."

Outside the rain had slackened into a fine mist. Overhead the clouds still held, but they were somewhat lighter. In a short while, it would be dawn. Every light in the compound was burning fiercely. Gallifa suddenly remembered the generator in the shack behind the Administration Building. If anyone smashed or damaged the generator beyond repair, the camp would be without power of any kind. And they might be forced to warn the colonists to stay away from the planet.

He stopped MacFarland. "I think we better secure the door to the generator shack," he said thoughtfully. "We can put a robot control on the radio, but we have to insure power."

MacFarland understood the reason immediately. But before he could answer angry voices rang out somewhere across the compound.

Gallifa hesitated. "You better see what that is," he told MacFarland. "And I'll check the generator."

MacFarland nodded and slipped away. Gallifa detoured around the hospital and carefully approached the Administration Building. Once he saw something moving in the half-light and halted abruptly. It was only a few of the little gnomes moving through the camp.

Gallifa quickly rummaged through the spare parts cache in the shack and drove stout pegs into the door jamb and the door. Then he expertly wove a short length of wire around the pegs and drew them tight with a pair of wire nippers. He leaned a shoulder against the door until he was satisfied it would hold. Then he returned to the hospital.

MacFarland met him at the back entrance. The five corpses still lay shackled to the bunks in a mute and grisly reminder of how quickly deterioration had spread through the embryonic colony. Gallifa felt his jaw muscles tighten.

"The bio team stole all the weapons," MacFarland said without preamble. "They've barricaded themselves in the mess hall and threaten to shoot anyone who comes within ten feet of the door."

Gallifa waited, his expression somber.

"The other teams are mad clear through," MacFarland continued. "I convinced them to go back to their own