Any indulgence frequently repeated would become a habit, in the sense that it would give no special pleasure when indulged in, but would make for stress if it were omitted.  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 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 one healthy in his mind,” he admitted.  “It works pretty well.  It satisfies all my mental appetites.  But there are instincts....”

She waited.  He did not finish.

“What do you do about the instincts that work and music and such things can’t satisfy?”

Calhoun grinned wryly, “I’m stern with them.  I have to be.”

He stood up and plainly expected her to go into the other cabin for the night.  She went.

It was after breakfast time of the next ship-day when he got out the sample of clear liquid he’d worked so long to produce.

“We’ll see how it works,” he observed.  “Murgatroyd’s handy in case of a slip-up.  It’s perfectly safe so long as he’s aboard and there are only the two of us.”

She watched as he injected half a cc. under his own skin.  Then she shivered a little.

“What will it do?”

“That remains to be seen.”  He paused a moment.  “You and I,” he said with some dryness, “make a perfect test for anything.  If you catch something from me, it will be infectious indeed!”

She gazed at him utterly without comprehension.

He took his own temperature.  He brought out the folios which were his orders, covering each of the planets he should give a standard Medical Service inspection.  Weald was there.  Dara wasn’t.  But a Med Service man has much freedom of action, even when only keeping up the routine of normal Med Service.  When catching up on badly neglected operations, he necessarily has much more.  Calhoun went over the folios.

Two hours later he took his temperature again.  He looked pleased.  He made an entry in the ship’s log.  Two hours later yet he found himself drinking thirstily and looked more pleased still.

He made another entry in the log and matter-of-factly drew a small quantity of blood from his own vein and called to Murgatroyd.  Murgatroyd submitted amiably to the very trivial operation Calhoun carried out.  Calhoun put away the equipment and saw Maril staring at him with a certain look of shock.