Greco got the answer after a while. Both types of demons were loose in the world, and both, by and by, were in every individual. But they didn't kill each other off. One simply grew more rapidly, took over control, until it ran out of the kind of molecules it needed. Then the other took over. Then the first. Then the other again.... Mice are short-lived. It's like balancing a needle on the end of your nose; there isn't enough space in a mouse's short span for balance, any more than there is in a needle's. But in a human life-- Things are going to have to be worked out, though. It's bad enough that a family gets all mixed up the way Greco's is--he's on a descending curve, his kid is on an aging curve, and Minnie--did I tell you that it was Minnie he married?--has completed her second rejuvenation and is on the way back up again. But there are worse problems that that. For one thing, it isn't going to be too long before we run out of space. I don't mean time, I mean space. _Living_ space. Because it's all very well that the human animal should now mature to grow alternately younger and older, over and over-- But, damn it, how I wish that somebody once in a while would _die_! --WILLIAM MORRISON * * * * *