"Rats," said Calhoun somehow angrily, "have been known to do that on a derelict ship. There was a man named Malthus who said we humans would some day do the same thing. But we haven't. We've take over a galaxy. If we ever crowd this, there are more galaxies for us to colonize, forever! But there have been cases of rats and rabbits multiplying past endurance. Here we've got an organic molecule that has multiplied out of all reason! It's normal for it to exist, but in a normal environment it's held in check by other molecules which in some sense feed on it; which control the population of this kind of molecule as rabbits or rats are controlled in a larger environment. But the check on this molecule isn't working, here!" * * * * * The booming voice of the Planetary President went on and on and on. Memoranda of events taking place were handed to him, and he read them and argued with the paras who had tried to rush the north gate of Government Center, to make its inhabitants paras like themselves. But the Planetary President tried to make oratory a weapon against madness. Calhoun grimaced at the voice. He said fretfully: "There's a molecule which has to exist because it can. It's a part of a normal environment, but it doesn't normally produce paras. Now it does! Why? What is the compound or the condition that controls its abundance? Why is it missing here? What is lacking? What?" The police-frequency speaker suddenly rattled, as if someone shouted into a microphone. "_All police cars! Paras have broken through a building wall on the west side! They're pouring into the Center! All cars rush! Set blasters at full power and use them! Drive them back or kill them!_" The grid operator turned angry, bitter eyes upon Calhoun. "The paras--we paras!--don't want to be cured!" he said fiercely. "Who'd want to be normal again and remember when he ate scavengers? I haven't yet, but--who'd be able to talk to a man he knew had devoured ... devoured--" The grid operator swallowed. "We paras want everybody to be like us, so we can endure being what we are! We can't take it any other way--except by dying!" He stood up. He reached for the blaster Calhoun had put aside when he changed from the clothes he'd worn in the city. "...And I'll take it that way!" Calhoun whirled. His fist snapped out. The grid operator reeled out. The blaster dropped from his hand. Murgatroyd cried out shrilly, from his cubbyhole. He hated violence, did Murgatroyd. Calhoun stood over the operator, raging: "It's not that bad yet! You haven't yawned once! You can stand the need for monstrousness for a long while yet! And I need you!" He turned away. The President's voice boomed. It cut off abruptly. Another voice took its place. And this was the bland and unctuous voice of Dr. Lett.