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."