He shrugged. "How do I know? Ask me in another ten years. _Look at me, Virgie!_" he cried, suddenly loud. "How old do I look to you? Eighteen? Twenty?" It was the plain truth. He looked no more than that. Seeing him day by day, I wasn't conscious of change; remembering him from when we had gone to school, I thought of him as younger anyway. But he was forty, at the very least, and he didn't look old enough to vote. He said, "I've had demons inside of me for six years. It seems they're a bit choosy about where they'll live. They don't inhabit the whole body, just parts of it--heart, lungs, liver. Maybe bones. Maybe some of the glands--perhaps that' s why I feel so chipper physically. But not my brain, or not yet. Fortunately." "Fortunately? But that's wrong, Greek! If your brain grew younger too--" "Fool! If I had a young brain, I'd forget everything I learned, like unrolling a tape backwards! That's the danger, Virgie, the immediate danger that's pressing me--that's why I needed help! Because if I ever forget, that's the end. Not just for me--for everybody; because there's no one else in the world who knows how to control these things at all. Except me--and you, if I can train you." "They're loose?" I felt my hair wonderingly. Still, it was not exactly a surprise. "How many?" He shrugged. "I have no idea. When they let the first batch of rabbits loose in Australia, did they have any idea how many there would be a couple of dozen generations later?" I whistled. Minnie popped her head in the door and giggled. I waved her away. "She could use some of your demons," I remarked. "Sometimes I think she has awfully young ideas, for a woman who's sixty if she's a day." Greco laughed crazily. "Minnie? She's been working for me for a year. And she was eighty-five when I hired her!" "I can't believe you!" "Then you'll have to start practicing right now," he said. It was tough, and no fooling; but I became convinced. It wasn't the million dollars a year any more. It was the thought of ending my days as a drooling, mewling infant--or worse! To avert that, I was willing to work my brain to a shred. * * * * * First it was a matter of learning--learning about the "strange particles." Ever hear of them? That's not my term--that's what the physicists call them. Positrons. The neutrino. Pions and muons, plus and minus; the lambda and the antilambda. K particles, positive and negative, and anti-protons and anti-neutrons and sigmas, positive, negative and neutral, and-- Well, that's enough; but physics had come a long way since the classes I cut at Old Ugly, and there was a lot to catch up on. The thing was, some of the "strange particles" were stranger than even most physicists knew. Some--in combination--were in fact Greco's demons.