"In order to keep the Brain mentally activated," V'Naric finished for him. "Precisely. To those savages it is nothing more than a religious ritual, brought about by the revenge motive. But to us it is a scientific necessity. The Brain teaches us much. It was the Brain which thought out all our technicalities of space travel and most of our other achievements. By now it realizes we have no intention of letting it die; but periodically its thought-processes seem exhausted. When it feels that happening it informs us. Then we must activate it again, through the accumulative mental-hysteria of those thousands of little Proktols. It is easy to steal their Shining Stone, keep it safely in our custody awhile, and bring some hapless spacefarer here for them to vent their hysteria upon. A little complex and a little sardonic, but very necessary." Janus, listening, nodded dully. He was remembering the huge fleet of space-ships they had seen waiting out on the desert; but he did not mention them. Instead he said: "And right now, what scientific problem is the Brain working on?" V'Naric seemed proud to talk of the Brain, appreciative of Janus' scientific interest in it. "We can never quite tell what the Brain is thinking," he explained. "It propounds scientific theories to us, we put them to the test, and they are usually practical. But this I know: lately a change has come over it. We are sure it is planning something big. It never used to question us much, but now it is beginning to, about other planets, the solar system, the universe. Then it ponders. "You see, it has never been away from here. It is restless now and I think it has ambitions! But we shall learn its plans when it has thought them through. From the astronomical data we have furnished it propounds vast calculations. Mathematically it is supreme! And it ponders...." * * * * * Now, suddenly, the sound below burst forth into a tremendous surge of unified shrilling. Hysteria. That's the word V'Naric had used, and this sounded like it! As if something interesting had started to happen. They turned quickly to the window again. Yes, something had begun to happen. There was a wide flow of red down Ketrik's cheek. The sharp-fanged little beasts under the cage had begun their work, just as V'Naric had said they would. Another of them darted forward. Ketrik's head jerked, but it was useless. Another flow of red started down; again came the surge of hysterical sound. No man should have watched that scene long, but they couldn't tell how many minutes they stood there at the window. Blake cracked first. He whirled away suddenly toward the doorway. But V'Naric had silently gone, and the crackling sheet of flame across the entrance filled the room with a bluish glow. Blake stood tottering a moment, horror still in his eyes, a little moan deep in his throat; then he staggered over and flopped into a bunk at the side of the room, turning his face away.