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.

"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