"They must have! Maybe they only came a few years ago, maybe only months ago. But when they tried to invade the unintelligent creatures the exploratory ship found here, they discovered that the new host's body couldn't tolerate them. His body reacted as if they were parasitic invaders, and built up antibodies against them. And those body defenses were more than the virus could cope with."
Dal pointed to the piles of notes on the desk. "Don't you see how it adds up? Right from the beginning we've been assuming that these monkey-like creatures here on this planet were the dominant, intelligent life-forms. Anatomically they were ordinary cellular creatures like you and me, and when we examined them we expected to find the same sort of biochemical reactions we'd find with any such creatures. And all our results came out wrong, because we were dealing with a combination of two creatures—the host and a virus. Maybe the creatures on 31 Brucker VII were naturally blank-faced idiots before the virus came, or maybe the virus was forced to damage some vital part just in order to fight back—but it was the virus that was being killed by its own host, not the other way around."
Jack studied the idea, no longer scornful. "So you think the virus-creatures called for help, hoping we could find some way to free them from the hosts that were killing them. And when Fuzzy developed a powerful antibody against them, and we started using the stuff—" Jack broke off, shaking his head in horror. "Dal, if you're right, we were literally slaughtering our own patients when we gave those injections down there!"
"Exactly," Dal said. "Is it any wonder they're so scared of us now? It must have looked like a deliberate attempt to wipe them out, and now they're afraid that we'll go get help and really move in against them."
Tiger nodded. "Which was precisely what we were planning, if you stop to think about it. Maybe that was why they were so reluctant to tell us anything about themselves. Maybe they've already been mistaken for parasitic invaders before, wherever in the universe they came from."
"But if this is true, then we're really in a jam," Jack said. "What can we possibly do for them? We can't even repair the damage that we've already done. What sort of treatment can we use?"
Dal shook his head. "I don't know the answer to that one, but I do know we've got to find out if we're right. An intelligent virus-creature has as much right to life as any other intelligent life-form. If we've guessed right, then there's a lot that our intelligent friends down there haven't told us. Maybe there'll be some clue there. We've just got to face them with it, and see what they say."
Jack looked at the viewscreen, at the angry mob milling around on the ground, held back from the ship by the energy screen. "You mean just go out there and say, 'Look fellows, it was all a mistake, we didn't really mean to do it?'" He shook his head. "Maybe you want to tell them. Not me!"
"Dal's right, though," Tiger said. "We've got to contact them somehow. They aren't even responding to radio communication, and they've scrambled our outside radio and fouled our drive mechanism somehow. We've got to settle this while we still have an energy screen."
There was a long silence as the three doctors looked at each other. Then Dal stood up and walked over to the swinging platform. He lifted Fuzzy down onto his shoulder. "It'll be all right," he said to Jack and Tiger. "I'll go out."