terrific strain told in definite terms on all, no matter what
stimulants they took to keep going. Many a man would have been driven
to insanity by their sustained, terrible concentration, and the
knowledge that five lives hung on every action, however minute....

On and on and on, science made into a marathon. Four hours of
exhausted, deathlike sleep; eight hours more of the smells, and the
glaring light, and the moving instruments. Days of this, sealing the
brains permanently into their new homes, into their hideous new
bodies....

But finally came the climax, and the last exhausted spurt of work. For
the concluding twelve hours there was no sleep or rest for anyone; and
at the end a breathless, haggard tension held them as Dr. Ku Sui, a
shell of his former self, reviewed the results of the nine days'
ordeal. His verdict was:

"Four have come through, I think, safe. The fifth--I do not know. His
body was near death when he was brought here. He may live or die; it
is impossible to tell now. But it is finished."

Then the men slept. Some slipped to the floor and slept where they
were. In nine days, the work of a month had been done, and a miracle
wrought. The brains had been born again.

CHAPTER XII

_Flight_

It was to Hawk Carse that the news of imminent danger came first.

He had staggered from the laboratory into a sleeping room and, clad as
he was, fallen over into a berth. He would have wakened in a few
hours, such was his custom of years to four-hour watches on ships, but
he was permitted less than an hour of sleep. A hand pulled at him; a
voice kept calling his name. Awareness returned to him slowly as his
brain roused from the coma of sleep.

"Captain Carse! Captain Carse! Wake up, sir!"

It was one of Leithgow's assistants, a man named Thorpe. His tone was
excited and his manner distraught.

"Yes?" the Hawk muttered thickly. "What is it?"

"It's the asteroid, sir! I was instructed to watch it at intervals,
but I--I guess I fell asleep, and just now--"

Carse sat up. "Yes? What?"

"--when I looked, through the glasses--it was gone!"

"Gone? You're sure? Let me see."

Swiftly, Thorpe at his heels, Carse strode out from the room to a
cubby just off the laboratory, the watch-post, where observational
electelscopes and visi-screens provided a panorama of the surrounding
territory.

He gazed through the electelscope, which had been equipped with an
infra-red device and trained on the