he illness were nursing
and feeding the sick ones, but these unaffected ones were growing
scarcer and scarcer. The whole living population seemed resigned to
hopelessness, hardly noticing the strangers from the patrol ship.

But worst of all were those in the final stages of the disease,
wandering vaguely about the street, their faces blank and their jaws
slack as though they were living in a silent world of their own, cut off
from contact with the rest. "One of them almost ran into me," Jack said.
"I was right in front of him, and he didn't see me or hear me."

"But don't they have _any_ knowledge of antisepsis or isolation?" Dal
asked.

Tiger shook his head. "Not that we could see. They don't know what's
causing this sickness. They think that it's some kind of curse, and
they never dreamed that it might be kept from spreading."

Already Tiger and Jack had taken the first routine steps to deal with
the sickness. They gave orders to move the unaffected people in every
town and village into isolated barracks and stockades. For half a day
Tiger tried to explain ways to prevent the spread of a bacteria or
virus-borne disease. The people had stared at him as if he were talking
gibberish; finally he gave up trying to explain, and just laid down
rules which the people were instructed to follow. Together they had
collected standard testing specimens of body fluids and tissue from both
healthy and afflicted Bruckians, and come back to the _Lancet_ for a
breather.

Now all three doctors began work on the specimens. Cultures were
inoculated with specimens from respiratory tract, blood and tissue taken
from both sick and well. Half a dozen fatal cases were brought to the
ship under specially controlled conditions for autopsy examination, to
reveal both the normal anatomical characteristics of this strange race
of people and the damage the disease was doing. Down on the surface
Tiger had already inoculated a dozen of the healthy ones with various
radioactive isotopes to help outline the normal metabolism and
biochemistry of the people. After a short sleep period on the _Lancet_,
he went back down alone to follow up on these, leaving Dal and Jack to
carry on the survey work in the ship's lab.

It was a gargantuan task that faced them. They knew that in any race of
creatures they could not hope to recognize the abnormal unless they knew
what the normal was. That was the sole reason for the extensive
biomedical surveys that wer