riday greeted them with another wide grin, and would again have bludgeoned the Eurasian with his wit had not the Hawk motioned him to silence. Looking at Dr. Ku, he said:

"I have Friday posted here because of the secret panel somewhere in this wall. You escaped through it before—do you remember?"

"Of course I remember. And if I'd had merely a fraction of your luck then, my present situation would be quite different."

"Perhaps," said the Hawk. "This panel is now the unknown quantity so far as I'm concerned, and I don't like unknown quantities; so I am asking you to show me where it is and how it works. That's my favor. Of course you can refuse to reveal it, but that will not delay me very long. The method of compulsion I mentioned...."

Dr. Ku-Sui appeared to reflect a moment, but his decision was not tardy in coming. He smiled.

"You terrify me, Captain, with your ominous hints about compulsion. I suppose I'd better be reasonable and show it to you. Really, though, your concern over the panel is rather wasted, inasmuch as it conceals nothing more than a small escape passage leading out of this building. Nothing important at all."

But his words, Carse somehow felt, were a screen; something else lay beneath them. He watched the tall figure with its always present odor of tsin-tsin blossoms move forward in a few indecisive steps, then back again, considering. The smile and the easy words were a camouflage, surely—but for what?

"Nothing important at all." Dr. Ku Sui repeated pleasantly. "Come. I will show you. Friday—if I may so address you—over on that switchboard you will find a small lever-control. It is the one with a Chinese character above it. Will you be so kind as to throw it?"

The Negro glanced inquiringly at his master. Grimly Carse nodded.

An enigmatic light glimmered in the Eurasian's green eyes as they watched the Negro go to the switchboard and put thumb and forefinger on the control.

"Only a small escape passage," he said deprecatingly as the Hawk crouched, gun ready, his eyes on the suspected place in the wall.

Friday threw the switch.

Immediately there sounded a short, sharp explosion. And acrid smoke billowed out from under the case of coordinated brains!

arse sprang to Ku Sui, gripped one arm and cried harshly:

"What have you done?"

"Not I, Captain—your obedient servant, the Black. Please, your fingers—" He removed them from his arm; and then, smiling, he said:

"I am afraid that all your assurance, your threats, are now but so much wasted breath."

"You mean—?"

"Surely, Captain," said Ku Sui, "you must have known I would provide for such an emergency, as this. I chose not to risk your darkly-hinted method of compulsion, and so had Friday remove the need for it. The Chinese character above the switch stands for 'Death.'"

Frigidly the Hawk asked: "You've destroyed the brains?"

"I have destroyed the brains." The Eurasian's voice was deep with a strange, unusual tone. "No matter: it was time. I am far, far ahead of that work, great though it was; it has destroyed itself with its inherent, irremediable fault. Yes, far ahead. Next time...." He appeared to lapse into profound and melancholy reflections; seemed to forget entirely the two men by him.

But the Hawk acted.

"We'll see," he said curtly. "Friday, watch the Doctor closely; this trick may be only the first." An intent, grim figure, he strode to the case of coordinated brains, pulled over the first of its two controlling switches, and stood silent while slowly the pulsings of light grew through the inner liquid and very slowly irradiated the five gray, naked mounds that were human brains. The light came to full, and Carse threw over the second switch. He said into the grille:

"I am Captain Carse. I wish to know if you are aware of what has just happened. Do you hear me, and did you feel anything a minute ago?"

ilence. Friday, close to the Eurasian and watchful, hung breathless, hoping that words might come from the grille in answer. But the silken figure he watched was there only in body; Dr. Ku's mind was in a far space of his own.

Cold, unhuman words spoke out.

"Yes, Captain Carse, I hear you. I felt the vibrations of the explosion that occurred a minute ago."

"Hah!" grunted Friday, immediately relieved. "All bluff, suh! No damage to 'em at all!"

Carse asked quickly into the grille:

"You felt the explosion, but do you know what it meant?—what it did?"

Again a pause; and again the toneless voice:

"A vital part of the machinery through which I live his been destroyed. I have left only some three hours of life."

The Hawk returned to Ku Sui. "Is that true?" he snapped.

"Yes, Captain." The words made a whisper, gentle and melancholy, coming from afar. A man was turning back from the scanning of the long years of one phase of his life. "Three hours is all that is left to them.... But there was a fault inherent in such coordinated brains; it is just as well that they are going.... Ah, Carse. I am so far ahead of you ... but I tell you it is a painful thing to destroy so wonderful a work of my hands...."

Silence filled the laboratory. It was broken by the awful voice of the living dead.

"I release you from your second promise, Captain Carse. No doubt what happened was beyond your control.... I will soon be dead. Although there is still nourishment in my liquid, I grow weaker already. I am dying...."

Harshly, the Hawk asked a final question into the grille:

"Within what time will you retain the vitality necessary to undergo the initial steps of the transplanting operations? Do you know?"

Dr. Ku raised his head at this, though he seemed only mildly interested in what the reply would be.

"I think for two of the remaining three hours."

"All right!" said Hawk Carse decisively. He threw off the case's switches. "Dr. Ku," he said, "you've only succeeded in accelerating things. Now for speed! Friday, we're taking this asteroid to Eliot Leithgow's laboratory. Go see that the port-lock doors are closed tight, then you and Wilson hurry back here! Fast! Run!"