hard lump at the base of the neck. There it was a
fair-sized organism. Elsewhere he could find nothing, until the black
specks developed.

His eyes ached from trying to see more than was visible in the
microscope. The tantalizing suggestions of filaments around the nuclei
might be the form of plague that was contagious. They might even be the
true form of the bug, with the bigger cell only a transition stage.
There were a number of diseases that involved complicated changes in the
organisms that caused them. But he couldn't be sure.

He finally buried his head in his hands, trying to do by pure thought
what he couldn't do in any other way. And even there, he lacked
training. He was a doctor, not a xenobiologist. Research training had
been taboo in school, except for a favored few.

The reports continued to come in, confirming the danger. They seemed to
have the worst plague on their hands in all human history; and nobody
who could do anything about it even knew of it.

"Molly reports that your letter got some results," Jake reported. "Chris
Ryan brought home one of the electron microscopes and a bunch of
equipment from the hospital pathology room. Think she'll get anywhere?"

Doc doubted it. Damn it, he hadn't meant for her to try it, though she
might have authority for routine experiments. But it was like her to
refuse to pass on the word without trying to prove her own suspicion of
him first.

He tried to comfort himself with the fact that some men were immune, or
seemed so; about three out of a hundred showed no signs. If that
immunity was hereditary, it might save the race. If not....

Jake came in at twilight with a grim face. "More news from Molly. The
Lobby is starting out to comb every village with a fault-finder,
starting here. And this hole will show up like a sore thumb. Better
start packing. We gotta be out of here in less than an hour!"

VIII

Fool

Three days later, Doc saw his first runner.

The tractor was churning through the sand just before sundown, heading
toward another one-night stand at a new village. Lou was driving, while
Doc and Jake brooded silently in the back, paying no attention to the
colors that were blazoned over the dunes. The cat-and-mouse game was
getting to Doc. There was no real assurance that the village they were
approaching might not be the target the Lobby had chosen for the next
investigation.

Lou braked the tractor to a sudden halt, and pointed.

A f