When we got upstairs, I turned to McGill. "Explain to Molly," I said. "And incidentally to me. I'm not properly briefed yet." He did so, and when he got to the summing up, I had the feeling she was a jump ahead of him. "In other words, you think it's something organic?" "Well," McGill said, "I'm trying to think of anything else it might be. I'm not doing so well," he confessed. "But so far as I can see," Molly answered, "it's mere probability, and without any over-all pattern." "Not quite. It has a center. Alec is the center." * * * * * Molly looked at me with a curious expression for a moment. "Do you _feel_ all right, darling?" she asked me. I nodded brightly. "You'll think this silly of me," she went on to McGill, "but why isn't it something like an overactive poltergeist?" "Pure concept," he said. "No genuine evidence." "Magnetism?" "Absolutely not. For one thing, most of the objects affected weren't magnetic--and don't forget magnetism is a force, not a form of energy, and a great deal of energy has been involved. I admit the energy has mainly been supplied by the things themselves, but in a magnetic field, all you'd get would be stored kinetic energy, such as when a piece of iron moves to a magnet or a line of force. Then it would just stay there, like a rundown clock weight. These things do a lot more than that--they go on moving." "Why did you mention a crystal before? Why not a life-form?" "Only an analogy," said McGill. "A crystal resembles life in that it has a definite shape and exhibits growth, but that's all. I'll agree this--thing--has no discernible shape and motion _is_ involved, but plants don't move and amebas have no shape. Then a crystal feeds, but it does not convert what it feeds on; it merely rearranges it into a non-random pattern. In this case, it's rearranging random motions and it has a nucleus and it seems to be growing--at least in what you might call improbability." Molly frowned. "Then what _is_ it? What's it made of?" "I should say it was made of the motions. There's a similar idea about the atom. Another thing that's like a crystal is that it appears to be forming around a nucleus not of its own material--the way a speck of sand thrown into a supersaturated solution becomes the nucleus of crystallization." "Sounds like the pearl in an oyster," Molly said, and gave me an impertinent look. "Why," I asked McGill, "did you say the coins couldn't have the same date? I mean apart from the off chance I got them that way." "Because I don't think this thing got going before today and everything that's happened can all be described as improbable motions here and now. The dates were already there, and to change them would require retroactive action, reversing time. That's out, in my book. That telephone now--" The doorbell rang. We were not surprised to find it was the telephone repairman. He took the set apart and clucked like a hen.