the worst--is
still coming. Right here, Frank..."

The case showed several small, urn-like growths, sectioned like the
other specimens.

Frank Nelsen grinned slightly. "All right--let me tell it," he said.
"Because this is something I really paid attention to! Like you imply,
their equipment is alive. So they work best with life--viruses, germs,
vegetable-allergy substances. These are their inventing, developing and
brewing bottles--for the numerous strains of Syrtis Fever virus. The
living molecule chains split off from the inner tissue walls of the
bottles, and grow and multiply in the free fluid. At least, that's how I
read it."

"And that is where my lab job begins, Frank," she told him. "Helping
develop anti-virus shots--testing them on bits of human tissue, growing
in a culture bath. An even partially effective anti-virus isn't found
easily. And when it is, another virus strain will soon appear, and the
doctors have to start over... Oh, the need isn't as great, any more, as
when the Great Rush away from Mars was on. There are only half a dozen
really sick people in the hospital now. Late comers and snoopers who got
careless or curious. You've got to remember that the virus blows off the
thickets like invisible vapor. There's one guy from Idaho--Jimmy--James
Scanlon. Come along. I'll show you, Frank..."

He lay behind plastic glass, in a small cubicle. A red rash, with the
pattern of frostwork on a Minnesota windowpane in January, was across
his lean, handsome face. Maybe he was twenty--Nance's age. His bloodshot
eyes stared at terrors that no one else could see.

Nance called softly through the thin infection barrier. "Jimmy!"

He moaned a little. "Francy..."

"High fever, Frank," Nance whispered. "Typical Syrtis. He wants to be
home--with his girl. I guess you know that nostalgia--yearning terribly
for old, familiar surroundings--is a major symptom. It's like a command
from _them_--to get out of Mars. The red rash is something extra he
picked up. An allergy... Oh, we think he'll survive. Half of them now
do. He's big and strong. Right now, even the nurses don't go in there,
except in costumes that are as infection-tight as armor. Later on, when
the fever dwindles to chronic intermittence, it will no longer be
contagious. Even so, the new laws on Earth won't let him return there
for a year. I don't know whether such laws are fair or not. We've got a
hundred here, who were sick, and are now stranded and wai