igure was running frantically over one of the low dunes with the
little red sun behind him. He seemed headed toward them, but as he drew
nearer they could see that he had no definite direction. He simply ran,
pumping his legs frantically as if all the devils of hell were after
him. His body swayed from side to side in exhaustion, but his arms and
legs pumped on.

"Stop him!" Jake ordered, and Lou swung the tractor. It halted squarely
in the runner's path, and the figure struck against it and toppled.

The legs went on pumping, digging into the dirt and gravel, but the man
was too far gone to rise. Jake and Lou shoved him through the doors into
the tractor and Doc yanked off his aspirator.

The man was giving vent to a kind of ululating cry, weakened now almost
to a whine that rose and fell with the motion of his legs. Sweat had
once streaked his haggard face, but it was dry and blanched to a pasty
gray.

Doc injected enough narcotic to quiet a maddened bull. It had no effect,
except to upset the rhythm of the arms and legs. It took five more
minutes for the man to die.

The specks were larger this time--the size of periods in twelve-point
type. The lump at the base of the skull was as big as a small hen's egg.

"From Edison, like the others so far. Jack Kooley," Jake answered Doc's
question. "Durwood spent a lot of time here on his first expedition, so
it's getting the worst of it."

Doc pulled the aspirator mask back over the man's face and they carried
him out and laid him on a low dune. They couldn't risk returning the
corpse to its people.

This was only the primary circle of infection, direct from Durwood. The
second circle could be ten times as large, as the infection spread from
one to a few to many. So far it was localized. But it wouldn't stay that
way.

Doc climbed slowly out of the tractor, lugging his small supplies of
equipment, while Jake made arrangements for them to spend the night in a
deserted house. But the figure of the runner and his own failures to
find more about the disease kept haunting Doc. He began setting up his
equipment grimly.

"Better get some sleep," Jake suggested. "You're a mite more tired than
you think. Anyhow, I thought you told me you couldn't do any more with
what you've got."

Feldman looked at the supplies he had spread out, and shook his head
wearily. He'd been over every chemical and combination a dozen times,
without results that showed in the limited magnificat