"Describing your plan, you sounded almost ready to put it into effect on the spot."

"No! Of course I realize—Well, I see what you mean—I think." Westover was crestfallen.

Sutton smiled faintly.

"I think you do, Bill. To survive, we've got to be good parasites. That means before all, for the coming generations, that we keep our numbers down. A good parasite doesn't destroy or even overtax its host. We don't want to follow the sorry example of such unsuccessful species as the bugs of bubonic plague or typhoid; we'll do better to model ourselves on the humble tapeworm.

"Your idea is dangerous for the same reason. The monsters probably spend thousands of years in interstellar space; during that time they'll be living exclusively on their fat—the fuel they stored on Earth, and so will we. We've got a whole new history of man ahead of us, under such changed conditions that we can't begin to predict what turns it may take. There's a very great danger that men will proliferate until they kill their hosts. But imagine a struggle for Lebensraum when all the living space there is is a few thousand monsters capable of supporting a very limited number of people each—with your method giving an easy way to destroy these little worlds our descendants will inhabit. It's too much dynamite to have around the house."

Westover bowed his head, but he had caught a curiously expectant glint in Sutton's eyes as he spoke. He thought, and his face lightened. "Suppose we work out a way to record my idea, one that can't be deciphered by anyone unintelligent enough to be likely to misuse it. A riddle for our descendants—who should have use for it some day."

At last Sutton smiled. "That's better. You've thought it through to the end, I see.... This phase of our history won't last forever. Eventually, the monsters will come to another planet not too unlike Earth, because it's on such worlds they prey. A tapeworm can cross the Sahara desert in the intestine of a camel—"

His voice was drowned in a vast hissing roar. An irresistible pressure distorted the walls of the chamber and scythed its occupants from their feet. Sutton staggered drunkenly almost erect, fought his way across the tilting floor to make sure of his precious apparatus. He turned back toward the others, bracing himself and shouting something; then, knowing his words lost in the thunder, gestured toward the Earth they were leaving, a half-regretful, half-triumphant farewell.