piece of string," Harrison murmured with his eyes closed.

"Sure. Tie it in knots, weave a rope out of it, wind it around your finger; it's still string."

"Yeah."

"But how do you attack a pattern?" Cercy asked. And why couldn't he get some sleep? To hell with the Ambassador and his hordes of colonists, he was going to close his eyes for a moment....

ake up, Colonel!"

Cercy pried his eyes open and looked up at Malley. Besides him, Harrison was snoring deeply. "Did you get anything?"

"Not a thing," Malley confessed. "The philosophy must've had quite an effect on him. But it didn't work all the way. Darrig knew that he had wanted to kill the Ambassador, and for good and sufficient reasons. Although he felt differently now, he still had the feeling that he was betraying us. On the one hand, he couldn't hurt the Ambassador; on the other, he wouldn't hurt us."

"Won't he tell anything?"

"I'm afraid it's not that simple," Malley said. "You know, if you have an insurmountable obstacle that must be surmounted ... and also, I think the philosophy had an injurious effect on his mind."

"What are you trying to say?" Cercy got to his feet.

"I'm sorry," Malley apologized, "there wasn't a damned thing I could do. Darrig fought the whole thing out in his mind, and when he couldn't fight any longer, he—retreated. I'm afraid he's hopelessly insane."

"Let's see him."

They walked down the corridor to Malley's laboratory. Darrig was relaxed on a couch, his eyes glazed and staring.

"Is there any way of curing him?" Cercy asked.

"Shock therapy, maybe." Malley was dubious. "It'll take a long time. And he'll probably block out everything that had to do with producing this."

Cercy turned away, feeling sick. Even if Darrig could be cured, it would be too late. The aliens must have picked up the Ambassador's message by now and were undoubtedly heading for Earth.

"What's this?" Cercy asked, picking up a piece of paper that lay by Darrig's hand.

"Oh, he was doodling," Malley said. "Is there anything written on it?"

Cercy read aloud: "'Upon further consideration I can see that Chaos and the Gorgon Medusa are closely related.'"

"What does that mean?" Malley asked.

"I don't know," Cercy puzzled. "He was always interested in folklore."

"Sounds schizophrenic," the psychiatrist said.

Cercy read it again. "'Upon further consideration, I can see that Chaos and the Gorgon Medusa are closely related.'" He stared at it. "Isn't it possible," he asked Malley, "that he was trying to give us a clue? Trying to trick himself into giving and not giving at the same time?"

"It's possible," Malley agreed. "An unsuccessful compromise—But what could it mean?"

"Chaos." Cercy remembered Darrig's mentioning that word in his telephone call. "That was the original state of the Universe in Greek myth, wasn't it? The formlessness out of which everything came?"

"Something like that," Malley said. "And Medusa was one of those three sisters with the horrible faces."

Cercy stood for a moment, staring at the paper. Chaos ... Medusa ... and the organizing principle! Of course!

"I think—" He turned and ran from the room. Malley looked at him; then loaded a hypodermic and followed.

n the control room, Cercy shouted Harrison into consciousness.

"Listen," he said, "I want you to build something, quick. Do you hear me?"

"Sure." Harrison blinked and sat up. "What's the rush?"

"I know what Darrig wanted to tell us," Cercy said. "Come on, I'll tell you what I want. And Malley, put down that hypodermic. I haven't