Dell touched the massive dome of his skull. "Here within this brain of mine has been conceived a thing which will probably destroy a billion human lives in the coming years. D. triconus toxin in a suitable aerosol requires only a countable number of molecules in the lungs of a man to kill him. My brain and mine alone is responsible for that vicious, murderous discovery." "Egotism! Any scientist's work is built upon the pyramid of past knowledge." * * * * * "The weapon I have described exists. If I had not created it, it would not exist. It is as simple as that. No one shares my guilt and my responsibility. And what more do they want of me now? What greater dream of mass slaughter and destruction have they dreamed?" "They want you," said Curt quietly, "because they believe we are not the only ones possessing the toxin. They need you to come back and help find the antitoxin for D. triconus." Dell shook his head. "That's a blind hope. The action of D. triconus is like a match set to a powder train. The instant its molecules contact protoplasm, they start a chain reaction that rips apart the cell structure. It spreads like fire from one cell to the next, and nothing can stop it once it's started operating within a given organism." "But doesn't this sense of guilt--unwarranted as it is--make you _want_ to find an antitoxin?" "Suppose I succeeded? I would have canceled the weapon of an enemy. The military would know he could nullify ours in time. Then they would command me to work out still another toxin. It's a vicious and insane circle, which must be broken somewhere. The purpose of the entire remainder of my life is to break it." "When you are fighting for your life and the enemy already has his hands about your throat," Curt argued, "you reach for the biggest rock you can get your hands on and beat his brains in. You don't try to persuade him that killing is unethical." For an instant it seemed to Curt that a flicker of humor touched the corners of Dell's mouth. Then the lines tightened down again. "Exactly," he said. "You reach for a rock and beat his brains in. You don't wipe human life off the face of the Earth in order to reach that enemy. I asked you to come down here to help me break this circle of which I spoke. There has to be someone here--after I'm gone--" Dell's eyes shifted to the depths of shadows beyond the firelight and remained fixed on unseen images. "Me? Help you?" Curt asked incredulously. "What could I do? Give up science and become a truck gardener, too?" "You might say that we would be in the rock business," replied Dell. "Fighting is no longer on the level of one man with his hands about another's throat, but it _should_ be. Those who want power and domination should have to fight for it personally. But it has been a long time since they had to. * * * * *