“It doesn’t hurt him,” Calhoun explained.  “Right after he’s born there’s a tiny spot on his flank that has the pain-nerves desensitized.  Murgatroyd’s all right.  That’s what he’s for!”

“But he’s your friend!” said Maril.

Murgatroyd, despite his small size and furriness, had all the human attributes an animal which lives with humans soon acquires.  Calhoun looked at him with affection.

“He’s my assistant.  I don’t ask anything of him that I can do myself.  But we’re both Med Service.  And I do things for him that he can’t do for himself.  For example, I make coffee for him.”

Murgatroyd heard the familiar word.  He said, “Chee!”

“Very well,” agreed Calhoun.  “We’ll all have some.”

He made coffee.  Murgatroyd sipped at the cup especially made for his little paws.  Once he scratched at the place on his flank which had no pain nerves.  It itched.  But he was perfectly content.  Murgatroyd would always be contented when he was somewhere near Calhoun.

Another hour went by.  Murgatroyd climbed up into Calhoun’s lap and with a determined air went to sleep there.  Calhoun disturbed him long enough to get an instrument out of his pocket.  He listened to Murgatroyd’s heartbeat, while Murgatroyd dozed.

“Maril,” he said.  “Write down something for me.  The time, and ninety-six, and one-twenty over ninety-four.”

She obeyed, not comprehending.  Half an hour later, still not stirring to disturb Murgatroyd, he had her write down another time and sequence of figures, only slightly different from the first.  Half an hour later still, a third set.  But then he put Murgatroyd down, well satisfied.

He took his own temperature.  He nodded.

“Murgatroyd and I have one more chore to do,” he told her.  “Would you go in the other cabin for a moment?”

Disturbed, she went into the other cabin.  Calhoun drew a small sample of blood from the insensitive area on Murgatroyd’s flank.  Murgatroyd submitted with complete confidence in the man.  In ten minutes Calhoun had diluted the sample, added an anticoagulant, shaken it up thoroughly, and filtered it to clarity with all red and white corpuscles removed.  Another Med Ship man would have considered that Calhoun had had Murgatroyd prepare a splendid small sample of antibody-containing serum, in case something got out of hand.  It would assuredly take care of two patients.

But a Med Ship man would also have known that it was simply one of those scrupulous precautions a Med Ship man takes when using cultures from store.

Calhoun put the sample away and called Maril back.

“It was nothing,” he explained, “but you might have felt uncomfortable.  We simply had a bit of Med Service routine that had to be gone through.  It’s all right now.”

He offered no further explanation.  She said, “I’ll fix lunch.”  She hesitated.  “You brought some food from the first Weald ship.  Do you want to—­”