through the smoke. It fell to the ground
directly upwind from Calhoun. White smoke puffed up violently.

It was instinct that made Calhoun react as he did. He jerked the girl
Maril to her feet and rushed her toward the Med Ship. Smoke from the
flung bomb upwind barely swirled around him and missed Maril
altogether. Calhoun, though, got a whiff of something strange, not
scorched or burning vegetation at all. He ceased to breathe and
plunged onward. In clear air he emptied his lungs and refilled them.
They were then halfway to the ship, with Murgatroyd prancing on ahead.

But then Calhoun's heart began to pound furiously. His muscles
twitched and tensed. He felt extraordinary symptoms like an extreme of
agitation. He swore, but a Med Ship man would not react to such
symptoms as a non-medically-trained man would have done. Calhoun was
familiar enough with tear gas, used by police on some planets.

But this was different and worse. Even as he helped and urged Maril
onward, he automatically considered his sensations, and had it--panic
gas. Police did not use it because panic is worse than rioting.
Calhoun felt all the physical symptoms of fear and of gibbering
terror.

A man whose mind yields to terror experiences certain physical
sensations: wildly beating heart, tensed and twitching muscles, and a
frantic impulse to convulsive action. A man in whom those physical
sensations are induced by other means will, ordinarily, find his mind
yielding to terror.

Calhoun couldn't combat his feelings, but his clinical attitude
enabled him to act despite them. The three from Weald reached the base
of the Med Ship. One of their enemies had lost his rifle and need not
be counted. Another had fled from flames and might be ignored for some
moments, anyhow. But a blast-bolt struck the ship's metal hull only
feet from Calhoun, and he whipped around to the other side and let
loose a staccato rat-tat-tat of fire which emptied the rifle of all
its charges.

Then he opened the airlock door, hating the fact that he shook and
trembled. He urged the girl and Murgatroyd in. He slammed the outer
airlock door just as another blast-bolt hit.

"They--they don't realize," said Maril desperately. "If they only
knew...."

"Talk to them, if you like," said Calhoun. His teeth chattered and he
raged, because the symptom was of terror he denied.

He pushed a button on the control board. He pointed to a microphone.
He got at an oxygen bottle and inh