for investigation,
nonsense rituals for hard work. But the physicians of the Black Service
were always waiting to jerk wandering neophytes back to the scientific
disciplines that made the service of Hospital Earth so effective. The
Black Doctors would not tolerate sloppiness. "Show me the tissue,
Doctor," they would say. "Prove to me that what you say is so. Prove
that what you did was valid medicine...." Their laboratories were the
morgues and autopsy rooms of a thousand planets, the Temples of Truth
from which no physician since the days of Pasteur and Lister could
escape for long and retain his position.

The Black Doctors were the pragmatists, the gadflies of Hospital Earth.

For this reason it was surprising to hear Black Doctor Neelsen saying,
"Perhaps we are being too scientific, just now. When the creature has
exhausted our food stores, it will look elsewhere for food. Perhaps we
must cut at the tree and not at the root."

"A frontal attack?" said Jenkins.

"Just so. Its enzyme system is its vulnerability. Enzyme systems operate
under specific optimum conditions, right? And every known enzyme system
can be inactivated by adverse conditions of one sort or another. A
physical approach may tell us how in this case. Meanwhile we will be on
emergency rations, and hope that we don't starve to death finding out."
The Black Doctor paused, looking at the men around him. "And in case you
are thinking of enlisting help from outside, forget it. I've sent
plague-warnings out for Galactic relay. We have this thing isolated, and
we're going to keep it that way as long as I command this ship."

They went gloomily back to their laboratories to plan their frontal
attack.

That was the night that Hrunta disappeared.

* * * * *

He was gone when they came to wake him from his sleep period. His bunk
had been slept in, but he wasn't in it. In fact, he wasn't anywhere on
the ship.

"But he couldn't just vanish!" the Black Doctor burst out when they told
him the news. "Maybe he's hiding somewhere. Maybe this business was
working on his mind."

Green Doctor Stone took a crew of men to search the ship again, even
though he considered it a waste of precious time. He had his private
convictions about where Hrunta had gone.

So did every other man on the ship, including Jenkins.

The _hlorg_ had stopped eating. Huge and round and wet and ugly, it
squatted in the after-hold, quivering gently, wi