a galaxy of which a very small proportion had been explored and
colonized by humanity. The human race was now to be counted in
quadrillions on scores of hundreds of inhabited worlds, but the tiny Med
Ship seemed the least significant of all possible created things. It
could travel between star-systems and even star-clusters, but it was not
yet capable of crossing the continent of suns on which the human race
arose. And between any two solar systems the journeying of the Med Ship
consumed much time. Which would be maddening for someone with no work to
do or no resources in himself, or herself.

On the second ship-day Calhoun labored painstakingly and somewhat
distastefully at the little biological laboratory. Maril watched him in
a sort of brooding silence. Murgatroyd slept much of the time, with his
furry tail wrapped meticulously across his nose.

Toward the end of the day Calhoun finished his task. He had a matter of
six or seven cubic centimeters of clear liquid as the conclusion of a
long process of culturing, and examination by microscope, and again
culturing plus final filtration. He looked at a clock and calculated
time.

"Better wait until tomorrow," he observed, and put the bit of clear
liquid in a temperature-controlled place of safe-keeping.

"What is it?" asked Maril. "What's it for?"

"It's part of a job I have on hand," said Calhoun. He considered. "How
about some music?"

She looked astonished. But he set up an instrument and fed microtape
into it and settled back to listen. Then there was music such as she had
never heard before. Again it was a device to counteract isolation and
monotonous between-planet voyages. To keep it from losing its
effectiveness, Calhoun rationed himself on music, as on other things.
Calhoun deliberately went for weeks between uses of his recordings, so
that music was an event to be looked forward to and cherished.

When he tapered off the stirring symphonies of Kun Gee with
tranquilizing, soothing melodies from the Rim School of composers, Maril
regarded him with a very peculiar gaze indeed.

"I think I understand now," she said slowly, "why you don't act like
other people. Toward me, for example. The way you live gives you what
other people have to try to get in crazy ways,--making their work feed
their vanity, and justify pride, and make them feel significant. But you
can put your whole mind on your work."

He thought it over.

"Med Ship routine is designed to keep