as well protected as we thought, even with our fancy suits."

Fifteen minutes passed slowly before the medics returned, and five
minutes more before they had passed through the decontamination chambers
and were allowed into the ship proper. A ring of tense faces surrounded
them as they made their report.

* * * * *

The leader, a tall, bespectacled doctor named Stevelman, was the
spokesman. He shrugged when Colonel Petersen put forth the question
whose answer everyone waited for.

"I don't know," the medic replied. "I don't know what killed them.
There's dry bones out there, but no sign of anything that might have
done it. It's pretty hard to make a quick diagnosis on a skeleton,
Colonel."

"What about the one skeleton with the bubble helmet?" Peter Wayne asked.
"Did you see any sign of a full suit on him?"

Stevelman shook his head. "Not a sign, sir."

Colonel Petersen turned and glanced at Lieutenant Jervis. "Do you
remember what the circumstances were, Lieutenant?"

Jervis shrugged. "I don't recall it very clearly, sir. I honestly
couldn't tell you whether they were wearing suits or bubble-helmets or
anything. I was too upset at the time to make careful observations."

"I understand," Petersen said.

But the medic had a different theory. He pointed at Jervis and said,
"That's a point I've meant to make, Lieutenant. You're a trained space
scout. Your psychological records show that you're not the sort of man
given to panic or to become confused."

"Are you implying that there's something improper about my statement,
Dr. Stevelman?"

The medic held up a hand. "Nothing of the sort, Lieutenant. But since
you're not the sort to panic, even in such a crisis as the complete
destruction of the entire crew of your scout ship, you must have been
ill--partly delirious from fever. Not delirious enough to cause
hallucinations, but just enough to impair your judgment."

Jervis nodded. "That is possible," he said.

"Good," said Stevelman. "I have two tentative hypotheses, then." He
turned to the colonel. "Should I state them now, Colonel Petersen?"

"There's to be no secrecy aboard this ship, Doctor. I want every man and
woman on the ship to know all the facts at all times."

"Very well," the medic said. "I'd suggest the deaths were caused by some
unknown virus--or, perhaps, by some virulent poison that occurred
occasionally, a poisonous smog of some kind that had settled in the