nated. The asteroid,
to the naked eye, was invisible; it could attract no attention; its
occupants had all been disposed of. Certainly it seemed safe enough to
leave it unguarded for a while.

However, Eliot Leithgow took one precaution. Down in his own
laboratory again, in the midst of the work of transferring Dr. Ku's
operating equipment from the air-car, he called aside one of his
assistants and instructed him to go and survey the asteroid through
the infra-red device every ten minutes: and with this order the old
scientist dismissed the matter from his mind, and turned all his
energies to preparing the laboratory for the operations.

* * * * *

Under Ku Sui's directions his cases of equipment were brought in and
arrayed, and the various drills and delicate saws, and such other
instruments as worked by electricity, were connected. Everything was
sterilized. Rapidly the plain, square room assumed the appearance of
an operating arena, the five tables in the center, spotlessly white
and clean under the direct beams of the tubes hanging from the
ceiling, at the head of every table a stand on which were containers
of antiseptics, bottles of etheloid, a breathing cone, rolls of gauze
and other materials, and along the edge of the stand identical,
complete sets of fine instruments.

The case of coordinated brains was brought into the laboratory last.
The inner liquid was now dark and apparently lifeless; to the casual
eye, it would not have seemed possible that the five grayish mounds
immersed in the liquid held life. And, indeed, Leithgow looked at them
doubtfully.

"Are you sure they're still alive? Do you think there's still time?"
he asked Dr. Ku.

The Eurasian picked up a long, slender, tubelike instrument with a
dial topping it. Then, going to the brain-case, he touched a cleverly
concealed catch and a square pane set in the top of the case swung
back. He dipped the instrument he held into the liquid, and for a
moment stood silent, watching the dial. Then he took it out, re-closed
the pane and turned to Leithgow.

"A test," he explained. "The indicator, interpreted means we have
about forty-eight minutes in which to complete the first phase of the
transplantation of the brains into human heads. It might be done if we
start in eight minutes. But the human heads--?" He paused.

"Eight minutes!" said Leithgow worriedly. "Eight minutes for Carse to
come! He promised the bodies, bu