"Which is not understood," said Maxwell.

"A mutation of some sort," suggested Oop.

"Collins thought so," said Maxwell. "But he stood alone. I know I didn't agree with him, but that was before I was on the crystal planet. Now I'm not so sure. What happens when a race reaches an end, when, as a race, it has passed through childhood and middle age and now has reached old age? A race dying as a man does, dying of old age. What does it do, then? It could die, of course.. That's what one would expect of it. But suppose there was a reason that it couldn't die, suppose it had to hang on, had to stay alive for some overriding reason, that it could not allow itself to die?

"If ghostliness really is a mutation," said Oop, "if they knew it was a mutation, if they were so far advanced they could control mutation-"

He stopped and looked at Maxwell. "You think that's what might have happened?"

"I think it might," said Maxwell. "I am beginning to think very much it might."

Oop handed across the fruit jar. "You need a drink," he said. "And when you're through with it, I'll have one, myself."

Maxwell took the jar, holding it, not drinking right away. Oop reached out to the stack of wood, lifted a chunk in one massive fist and threw it on the fire. A spray of sparks gushed up the chimney. Outside the night wind moaned along the eaves.

Maxwell lifted the jar and drank. The splash of liquid ran down his gullet like a torrent of lava. He choked, wishing that he could drink the stuff, just once, without choking on it. He handed the jar back to Oop. Oop lifted it, then took it down again without drinking. He squinted across its rim at Maxwell.