without fission by-products. Matrix
mechanics had made the Darkovans virtually immune to the lure of Terra's
advanced technologies.

Jay said, "Personally I think Darkovan science is over-rated. But I can
see the propaganda angle--"

"Not to mention the humanitarian angle of healing--"

* * * * *

Jay Allison gave one of his cold shrugs. "The real angle seems to be
this; _can_ we cure the 48-year fever?"

"Not yet. But we have a lead. During the last epidemic, a Terran
scientist discovered a blood fraction containing antibodies against the
fever--in the trailmen. Isolated to a serum, it might reduce the
virulent 48-year epidemic form to the mild form again. Unfortunately, he
died himself in the epidemic, without finishing his work, and his
notebooks were overlooked until this year. We have 18,000 men, and their
families, on Darkover now, Jay. Frankly, if we lose too many of them,
we're going to have to pull out of Darkover--the big brass on Terra will
write off the loss of a garrison of professional traders, but not of a
whole Trade City colony. That's not even mentioning the prestige we'll
lose if our much-vaunted Terran medical sciences can't save Darkover
from an epidemic. We've got exactly five months. We can't synthesize a
serum in that time. We've got to appeal to the trailmen. And that's why
I called you up here. You know more about the trailmen than any living
Terran. You ought to. You spent eight years in a Nest."

* * * * *

(In Forth's darkened office I sat up straighter, with a flash of
returning memory. Jay Allison, I judged, was several years older than I,
but we had one thing in common; this cold fish of a man shared with
myself that experience of marvelous years spent in an alien world!)

Jay Allison scowled, displeased. "That was years ago. I was hardly more
than a baby. My father crashed on a Mapping expedition over the
Hellers--God only knows what possessed him to try and take a light plane
over those crosswinds. I survived the crash by the merest chance, and
lived with the trailmen--so I'm told--until I was thirteen or fourteen.
I don't remember much about it. Children aren't particularly observant."

Forth leaned over the desk, staring. "You speak their language, don't
you?"

"I used to. I might remember it under hypnosis, I suppose. Why? Do you
want me to translate something?"

"Not exactly. We were thinking of sending you