"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 were done on new contract planets. Under normal conditions, a survey crew with specialists in physiology, biochemistry, anatomy, radiology, pharmacology and pathology might spend months or even years on a new planet gathering base-line information. But here there was neither time nor facilities for such a study. Even in the twenty-four hours since the patrol ship arrived, the number of dead had increased alarmingly.

Alone on the ship, Dal and Jack found themselves working as a well organized team. There was no time here for argument or duplicated efforts; everything the two doctors did was closely co-ordinated. Jack seemed to have forgotten his previous antagonism completely. There was a crisis here, and more work than three men could possibly do in the time available. "You handle anatomy and pathology," Jack told Dal at the beginning. "You can get the picture five times as fast as I can, and your pathology slides are better than most commercial ones. I can do the best job on the cultures, once I get the growth media all set up."

Bit by bit they divided the labor, checking in with Tiger by radio on the results of the isotopes studies he was running on the planet's surface. Bit by bit the data was collected, and Earthman and Garvian worked more closely than ever before as the task that faced them appeared more and more formidable.

But the results of their tests made no sense whatever. Tiger returned to the ship after forty-eight hours with circles under his eyes, looking as though he had been trampled in a crowd. "No sleep, that's all," he said breathlessly as he crawled out of his decontaminated pressure suit. "No time for it. I swear I ran those tests a dozen times and I still didn't get any answers that made sense."

"The results you were sending up sounded plenty strange," Jack said.

"What was the trouble?"

"I don't know," Tiger said, "but if we're looking for a biological pattern here, we haven't found it yet as far as I can see."

"No, we certainly haven't," Dal exploded. "I thought I was doing something wrong somehow, because these blood chemistries I've been doing have been ridiculous. I can't even find a normal level for blood sugar, and as for the enzyme systems...." He tossed a sheaf of notes down on the counter in disgust. "I don't see how these people could even be alive, with a botched-up metabolism like this! I've never heard of anything like it."

"What kind of pathology did you find?" Tiger wanted to know.

"Nothing," Dal said. "Nothing at all. I did autopsies on the six that you brought up here and made slides of every different kind of tissue I could find. The anatomy is perfectly clear cut, no objections there.

These people are very similar to Earth-type monkeys in structure, with heart and lungs and vocal cords and all. But I can't find any reason why they should be dying. Any luck with the cultures?"

Jack shook his head glumly. "No growth on any of the plates. At first I thought I had something going, but if I did, it died, and I can't find any sign of it in the filtrates."

"But we've got to have _something_ to work on," Tiger said desperately.

"Look, there are some things that always measure out the same in _any_ intelligent creature no matter where he comes from. That's the whole basis of galactic medicine. Creatures may develop and adapt in different ways, but the basic biochemical reactions are the same."

"Not here, they aren't," Dal said. "Take a look at these tests!"

They carried the heap of notes they had collected out into the control room and began sifting and organizing the data, just as a survey team would do, trying to match it with the pattern of a thousand other living creatures that had previously been studied. Hours pa.s.sed, and they were farther from an answer than when they began.

Because this data did not fit a pattern. It was _different_. No two individuals showed the same reactions. In every test the results were either flatly impossible or completely the opposite of what was expected.

Carefully they retraced their steps, trying to pinpoint what could be going wrong.

"There's _got_ to be a laboratory error," Dal said wearily. "We must have slipped up somewhere."

"But I don't see where," Jack said. "Let's see those culture tubes again. And put on a pot of coffee. I can't even think straight any more."

Of the three of them, Jack was beginning to show the strain the most.

This was his special field, the place where he was supposed to excel, and nothing was happening. Reports coming up from the planet were discouraging; the isolation techniques they had tried to inst.i.tute did not seem to be working, and the spread of the plague was accelerating.

The communiques from the Bruckians were taking on a note of desperation.

Jack watched each report with growing apprehension. He moved restlessly from lab to control room, checking and rechecking things, trying to find some sign of order in the chaos.

"Try to get some sleep," Dal urged him. "A couple of hours will freshen you up a hundred per cent."

"I can't, I've already tried it," Jack said.

"Go ahead. Tiger and I can keep working on these things for a while."

"No, no, it's not that," Jack said. "Without a diagnosis, we can't do a thing. Until we have that, our hands are tied, and we aren't even getting close to it. We don't even know whether this is a bacteria, or a virus, or what. Maybe the Bruckians are right. Maybe it's a curse."

"I don't think the Black Service of Pathology would buy that for a diagnosis," Tiger said sourly.

"The Black Service would choke on it--but what other answer do we have?

You two have been doing all you can, but diagnosis is _my_ job. I'm supposed to be good at it, but the more we dig into this, the farther away we seem to get."

"Do you want to call for help?" Tiger said.

Jack shook his head helplessly. "I'm beginning to think we should have called for help a long time ago," he said. "We're into this over our heads now and we're still going down. At the rate those people are dying down there, we don't have time to call for help now." He stared at the piles of notes on the desk and his face was very white. "I don't know, I just don't know," he said. "The diagnosis on this thing should have been duck soup. I thought it was going to be a real feather in my cap, just walking in and nailing it down in a few hours. Well, I'm whipped. I don't know what to do. If either of you can think of an answer, it's all yours, and I'll admit it to Black Doctor Tanner himself."

It was bitter medicine for Blue Doctor Jack Alvarez to swallow, but that fact gave no pleasure to Dal or Tiger now. They were as baffled as Jack was, and would have welcomed help from anyone who could offer it.

And, ironically, the first glimpse of the truth came from the direction they least expected.

From the very beginning Fuzzy had been watching the proceedings from his perch on the swinging platform in the control room. If he sensed that Dal Timgar was ignoring him and leaving him to his own devices much of the time, he showed no sign of resentment. The tiny creature seemed to realize that something important was consuming his master's energy and attention, and contented himself with an affectionate pat now and then as Dal went through the control room. Everyone a.s.sumed without much thought that Fuzzy was merely being tolerant of the situation. It was not until they had finally given up in desperation and Tiger was trying to contact a Hospital Ship for help, that Dal stared up at his little pink friend with a puzzled frown.

Tiger put the transmitter down for a moment. "What's wrong?" he said to Dal. "You look as though you just bit into a rotten apple."

"I just remembered that I haven't fed him for twenty-four hours," Dal said.

"Who? Fuzzy?" Tiger shrugged. "He could see you were busy."

Dal shook his head. "That wouldn't make any difference to Fuzzy. When he gets hungry, he gets hungry, and he's pretty self-centered. It wouldn't matter what I was doing, he should have been screaming for food hours ago."

Dal walked over to the platform and peered down at his pink friend in alarm. He took him up and rested him on his shoulder, a move that invariably sent Fuzzy into raptures of delight. Now the little creature just sat there, trembling and rubbing half-heartedly against Dal's neck.

Dal held him out at arm's length. "Fuzzy, _what's the matter with you?_"

"Do you think something's wrong with him?" Jack said, looking up suddenly. "Looks like he's having trouble keeping his eyes open."

"His color isn't right, either," Tiger said. "He looks kind of blue."

Quite suddenly the little black eyes closed and Fuzzy began to tremble violently. He drew himself up into a tight pink globule as the fuzz-like hair disappeared from view.

Something was unmistakably wrong. As he held the shivering creature, Dal was suddenly aware that something had been nibbling at the back of his mind for hours. Not a clear-cut thought, merely an impression of pain and anguish and sickness, and now as he looked at Fuzzy the impression grew so strong it almost made him cry out.

Abruptly, Dal knew what he had to do. Where the thought came from he didn't know, but it was crystal clear in his mind. "Jack, where is our biggest virus filter?" he asked quietly.