"That accounts for the queer differences our pathologist found," the dean observed when the fact had been translated to him that these hordes of men were cultured in a laboratory. "Now that you have me in your power," the Martian continued, "please explain to me how you kept all your destructive engines hidden when I was here on my preparatory observation trip." The dean of the Medical School touched Haven on the shoulder. "Ask him how long ago he was here." "It took me," the machine said, "just about a thousand years (our year is twice as long as yours) to work out my methods of transportation, maintenance, and culture, and to make a voice instrument with which to talk to these culture-soldiers." The dean turned toward the Commanding Officer. "Two thousand years ago," he said. "The Romans were just about at the height of their military glory. Explain that to him, and how the world and its people have changed since." The queer, seaweed-like creature nodded in comprehension and settled itself down in its jar in resignation. "That is the point I overlooked. For millions of years, the Martians, at the zenith of scientific knowledge, have remained stable. The idea of human change, of progress in civilization, had slipped my mind. Our race has forgotten it. Your race progressed, and left me behind." A little discussion arose among them. All agreed that it would be most interesting and valuable to preserve the Martian carefully in some museum. A great deal of useful information could be obtained from him. Many benefits would accrue to humanity from his knowledge. "Only," reminded the Commanding Officer, "how much power does he still have left for doing harm?" The dean was interested, and bent close to the jar to have a better look. He put his hand on the glass. There was a quick rush and a crash of furniture. The big Roman general leaped up from beneath a couch, where he had been concealed. With sword upraised he dashed at the dean. "Look out!" shouted John. The Roman general gave a hoarse cry. Fortunately it took a goodly number of seconds for him to cross the room. The Commanding Officer was tugging at his pistol holder. His automatic came out fairly quickly and banged twice. The Roman came rushing on almost to within a foot of the muzzle. Then his sword dropped with a clatter on the floor, his helmet rolling several feet away. The case tipped. It toppled. It looked almost as though it would go over. Then it settled back; but a crackling sound came from it. A crack appeared in the glass, and wound spirally around it. There was a sizzle of air going into the jar. Machinery clicked and sparks crackled. The creature inside jerked convulsively, and then was still. In a few minutes it began to bloat, and a red mold spread rapidly over it.