d is. You know what blueskins are!"

"B--but what do you think they are?" she asked.

"There used to be a human disease called smallpox," said Calhoun. "When
people recovered from it, they were usually marked. Their skin had
little scar-pits here and there. At one time, back on Earth, it was
expected that everybody would catch smallpox sooner or later, and a
large percentage would die of it. And it was so much a matter of course
that if they printed a description of a criminal, they never mentioned
it if he were pock-marked--scarred. It was no distinction. But if he
didn't have the markings, they'd mention that!" He paused. "Those
pock-marks weren't hereditary, but otherwise a blueskin is like a man
who had them. He can't be anything else!"

"Then you think they're--human?"

"There's never yet been a case of reverse evolution," said Calhoun.
"Maybe pithecanthropus had a monkey uncle, but no pithecanthropus ever
went monkey."

She turned abruptly away. But she glanced at him often during that day.
He continued to busy himself with those activities which make a Med
Ship man's life consistent with retained sanity.

Next day she asked without preliminary;

"Don't you believe the blueskins planned for the ship with the dead men
to arrive at Weald and spread plague there?"

"No," said Calhoun.

"Why?"

"It couldn't possibly work," Calhoun told her. "With only dead men on
board, the ship wouldn't arrive at a place where the landing-grid could
bring it down. So that would be no good. And plague-stricken living men
wouldn't try to conceal that they had the plague. They might ask for
help, but they'd know they'd instantly be killed on Weald if they were
found to be plague-victims. So that would be no good, either! No, the
ship wasn't intended to land plague on Weald."

"Are you--friendly to blueskins?" she asked uncertainly.

"Within reason," said Calhoun, "I am a well-wisher to all the human
race. You're slipping, though. When using the word 'blueskin' you should
say it uncomfortably, as if it were a word no refined person liked to
pronounce. You don't. We'll land on Orede tomorrow, by the way. If you
ever intend to tell me the truth, there's not much time."

She bit her lips. Twice, during the remainder of the day, she faced him
and opened her mouth as if to speak, and then turned away again. Calhoun
shrugged. He had fairly definite ideas about her, by now. He carefully
kept them tentative, but no girl born and