by the
landing party went out through the ejection lock. Inside the ship, the
floors, walls, and ceilings were scoured by sweating men who worked
feverishly. Fumigants were spread in every room.

With the spreading of the fumigants, spirits began to rise, but even
then the signs of stress were still all too obvious. No one knew the
incubation period of the virus. Hours only had been needed to bring
Kurkil to his death. But days might pass before the virus developed in
its next victim.

Months or even years might pass before they were absolutely sure they
were free from any chance of infection.

By the time the ship reached Sol Cluster, and the automatic controls
stopped its hyper-flight, they might all be dead.

If that happened, the ship's controls would automatically stop its
flight. It would be picked up by the far-ranging screens of the space
patrol, a ship would be sent out to board it and bring it in.

At the thought of what would happen then, Thompson went hastily forward
to the control room. Grant, thin-lipped and nervous, was on duty there.
Thompson hastily began plotting a new course. Grant watched over his
shoulder.

"Make this change," Thompson said.

"But, Captain--" Grant protested. The man's face had gone utterly white
as he realized the implications of this new course. "No. We can't do
that. It'll mean--"

"I know what it will mean. And I'm in my right mind, I hope. This course
is a precaution, just in case nobody is left alive by the time we reach
Sol Cluster."

"But--"

"Make the change," Thompson ordered bluntly.

Reluctantly Grant fed the new course into the computers. A throb went
through the vessel as the ship shifted in response.

"We'll come out of hyper-flight in less than three hours," Grant spoke.
"Heaven help us if this course is not changed before that time."

"If this course is not changed before that time, Heaven alone can help
us. From now on, you're not to leave this control room for an instant."

"Yes, sir."

With Buster following behind him, Thompson left the control room.

"Yoooow!" The scream coming from the lounge this time was in a different
key and had a different sound. But the meaning was the same as it had
been when Kurkil had screamed. Thompson went forward on the run.

The victim was Ross. Like Kurkil, he was tearing his clothes off. Like
Kurkil, he was turning green. When he went down, he did not rise again.

As he stood staring down at Ross, Thompson