Читать книгу The City of the Sun - Brian Stableford - Страница 5

CHAPTER THREE

Nathan told the rest what had happened. He told it neatly and economically—but there really wasn’t all that much to tell. When he asked me if I had anything to add all I could say was: “It wasn’t exactly the greatest first contact in history.”

“You were in on it,” he pointed out. “I didn’t notice your telling contribution.”

I smiled, sweetly.

“This parasite...,” said Conrad.

“Ah,” I said, turning to him. “The matter in hand.”

It really wasn’t an appropriate time for levity, but I felt the need of a little levity to lighten my mood. I hadn’t seen much of Arcadia so far, but what little I had seen I hadn’t liked.

“It’s obviously not debilitating,” said Conrad. “The man who spoke to you seemed perfectly fit and healthy.”

“Well,” I said—and now I abandoned the levity—“if it was a man, I’d have to be cautious about guaranteeing certain aspects of his health. But if it was a woman, she was probably okay. A flat chest doesn’t count as a debility.”

“You really don’t know whether it was a man or a woman?” asked Karen.

I shook my plastic-sheathed head. “I wouldn’t even be prepared to make a statement about the archers,” I said. “And they were naked. They were too far away, and they were riding some rather hairy beasts bareback.”

“Why should they be naked?” Linda wanted to know. “You say that the people in the fields wore clothing.”

That particular guess fell into Nathan’s field of competence. I let him take it. “At a guess,” he said. “The clothing wasn’t so much for protection from the elements as a designation of rank. The one who spoke to us had a garment made out of very distinctive cloth. He obviously had some authority.”

“But not all that much,” I commented. “He had to report back. To the Ego, and to the Self...which may be the same person or organization, or two different ones.”

“Curious names,” observed Conrad.

“Ominous names,” Nathan corrected him.

I knew what he meant. We could have shrugged off “king,” or “master” or “parliament” or almost anything else familiar. Even “metaphysicus” wouldn’t have bothered us, because we’d looked up The City of the Sun and knew that that was what the top man in the romance was called. But “Self” and “Ego” weren’t words you’d normally associate with government, and it had seemed to me that the dark man—or woman—had such a precise way of speaking that it wasn’t safe to assume that the terms weren’t in some way specifically meaningful.

“It might just be a case of Utopian pretentiousness,” said Karen. “These people seem to have gone in for pretentiousness, judging by your description of the city.”

“This is a weird one,” I said, meditatively, inspecting my fingernails beneath the plastic gauntlet. “I think it might be weirder than we yet imagine.”

“Suppose they come back and tell us that they’ve decided to refuse our application,” said Linda. “What then?”

“Well,” I said. “It’ll be nothing new. We don’t exactly seem to be welcome wherever we go. The colonies haven’t rolled out a single red carpet so far, although they did give us a good dinner on Floria before they started shooting.”

“We’ve got to find out what’s happening here,” said Nathan. “Whether they appreciate our being here or not.”

“That plastic suit won’t stop an arrow,” I said, flatly.

“Never mind that,” said Conrad. “There’s no point in wasting time in speculative meandering when there’s real work to be done. For one thing, we have to try to identify this parasite. The survey team probably recorded its presence as a parasite of the herbivores, or some other local species. If we must speculate, let’s speculate as to why they weren’t infected.”

“They were only here fourteen months,” I reminded him. “And not precisely here, either—we’re several hundred miles from site prime...over a thousand, I think. There are any number of versatile parasites among the communal protozoa.... This particular one was probably a good deal rarer where the survey team spent the greater part of their time than it is here. But you’re right about identifying it.... Linda—can you feed in the data we have and get the computer to check against the classification tables? Get it to sort out data cards on anything that fits the basic description.”

Linda nodded, and went into the lab to start work on the problem. Once we had the cards codifying the survey team’s reports on various suspects we’d be able to get a better idea of what we were dealing with.

The computer didn’t take long to do the sort, and it finally belched forth four cards printed with abbreviated jargon. Linda tossed them to me, and I skimmed through them rapidly.

“I was afraid of that,” I murmured.

“What?” asked Nathan.

“Here we have four parasites which form black dendritic webs on the outer skin of their hosts. But all four hosts are small mammals of no economic importance or ecological interest. Rabbits and field mice, as near as damn it.”

“So?”

“They didn’t find it in association with the oxen,” I said, patiently. “If they had, they’d have taken a lot more interest in it. The oxen are useful, valuable animals. Their diseases were a matter of considerable import in assessing the potential of a colony here—their presence provided a possible source of meat, transport and farm labor. But who’s interested in rabbits and field mice? The survey team did no more than a routine bioscan on this lot, whereas if they’d found it among the oxen—from which the people here presumably caught it—they’d have looked at it much more closely.”

“Didn’t they realize it might infect humans?” asked Mariel.

I shook my head as I studied the cards more carefully, one by one. “They noted that the parasite was probably capable of infecting a range of compatible hosts. They didn’t realize how wide a range. But even if they had, they might not have considered it important. Most people, remember, don’t just sit back and let things grow all over them. They try to do something about it.”

That, of course, was one of the most worrying things. If the people of the city were all infected by this thing then they obviously hadn’t put up much of a fight. One of the first things the colonists would have done would have been to prepare some biotic defenses against their new environment. Simple medical technology is the first priority of any colony.

The cards told me that the dendrites ramified internally as well as externally, but only to a limited extent. The bulk of the biomass lay on the surface, with only thin threads—chains of potentially independent cells—linking it to the circulatory system and the nervous system of the host. The parasite was careful not to damage its hosts by too much disruption of the tissues. It didn’t feed on tissues—just leeched what it required from the bloodstream. A very considerate vampire, if appearances were to be believed. The surveyors reported that infected animals were at least as healthy as uninfected ones.

Then I saw something on one of the cards that made me put the others aside.

“If anyone wants to bet,” I said, “I’ll lay six to four on this one as the culprit.”

There were no takers, but they all wanted to know why.

“It’s the special one,” I told them. “It has a footnote that the survey team didn’t think was especially significant. It says here that this particular species goes in for inductive cellular mimicry. Especially with respect to nervous tissue.”

“Which means?” Nathan prompted.

“These communal protozoans are versatile,” I said. “It’s the key to their success. Some protozoan species on Earth are versatile enough to choose whether to be plants or animals—they can grow chloroplasts and dispose of them as circumstances dictate. The whole essence of communal aggregation is that it’s the beginnings of division of labor—some cells specialize in reproduction, others in energy fixation, others in defense. It happens in the colonial algae and in the colonial polyps. The point about communal aggregations, though, is that the cells retain their potential independence—and their potential choices. Organisms—multicellular organisms, that is—go in for a much more precise kind of specialization. Once a cell grows to its destined function it remains specialized. Once a liver cell, always a liver cell—the versatility of each individual cell is lost at an early stage in the development of an embryo when cells become fixed into their permanent function. This process of specialization is involved with a mechanism called induction, which causes different tissues to develop in the right places within the embryo in response to the stimuli provided by other tissues developing in the immediate environment.

“These parasites, being communal pseudo-organisms, retain essential versatility in each and every cell. Most of the species don’t make a lot of use of that versatility—parasitism is a relatively simple way of life, which doesn’t demand a great deal of differentiation of functions. But this one is a very highly developed parasite...a super-parasite. You can think of the others as plant-like things, sending tap roots down into the flesh of their hosts to soak up moisture and nourishment. It’s essentially a crude business, like drilling oil wells. The parasites are fairly discreet—they use thin drills, strands of cells only two or three thick—but what they do is nevertheless a fairly straightforward job of boring and mining.

“The odd man out is cleverer than that. His cells make use of their versatility by mimicking the cells of the host. Thus, when he sends a tap root down through skin tissue to the wall of a blood vessel, the strand cells take on many of the characteristics of dermal cells, and the cells which actually do the thieving take on many of the characteristics of blood-vessel-wall cells. This parasite then has a much higher degree of integration with his host. The host no longer recognizes him as an invader, and thus he becomes immune to the body’s natural tendency to reject foreign matter. The extra functions fulfilled by these cells—the parasite functions—are masked by the apparent conformity of the cells to their immediate tissue environment.

“I can’t tell from this report how far the mimicry goes. But if this parasite is really clever—and we have grounds to suspect that it is—then the mimic cells might actually carry out the functions of the tissues they mimic, so that as well as the tap root cells being indistinguishable from host-tissue cells by the host’s bodily defenses, they actually do the job they ought to be doing if they were host-tissue cells. That way, this particular parasite could maintain a much more extensive internal network than its relatives. It wouldn’t have to limit itself to a few discreet strands of cells—it could ramify much more extensively inside its host. And that would mean that it could support a much greater biomass all told—something like the formations we could see on these people, instead of just a little thing like a spider web on the back of a rabbit.

“Also, of course, this could explain why the colonists might have been unable to muster any kind of medical defense against this parasite. If its internal ramifications can mimic host cells well enough to fool the host body itself, no external antibiotic would get close to it...not without attacking the host tissues too. The external dendrites—the black cells—are probably fairly easy to dispose of...but if the colonists dispose of them they simply grow back from inside. The roots can’t be touched by any normal methods.

“In brief, I suspect that this is the most efficient parasite I’ve ever come across. Maybe it’s so efficient that it doesn’t deserve to be called a parasite—maybe just a commensal. It really cooperates with the host body, taking the nourishment it needs with the absolute minimum of biotic vandalism. Maybe the only thing we can say against it is that it isn’t very pretty. Maybe...I think I’ll reserve judgment on that until I get a much closer, much longer look.”

There was a respectful pause.

“You may applaud,” I told them.

They didn’t. Not that it mattered. I hadn’t planned an encore.

“If you’re right,” said Nathan, “then the obvious question is...can we find any way to attack such a parasite?”

“Oh yes,” I assured him. “Genetic engineering gives us much more subtle routes of attack than any antibiotic drug. We can actually attack the thing in its genes—the very genes which give it its versatility and its ability to mimic specialized cells. The parasite cells can only mask their real nature...and we have the means to get behind the mask. It probably won’t pose much of a problem to us, if only....”

“...if only we can persuade them that it’s a problem,” Nathan finished for me. I hated him pinching my punch line like that.

I shrugged. “People do get used to things,” I said. “They may not see this stuff quite as we see it. They may like black stripes growing all over them.”

“Well,” said Linda, with commendable pragmatism, “if the parasite really doesn’t do them any harm, they can afford to like it, can’t they? And we can afford to let them.”

“I think,” I said, “that I’d like to reserve judgment on that issue too. Until I’ve had a much longer and much closer look. I’ve got this strong suspicion, still, that there’s a lot more to this than we’ve so far guessed.”

“Isn’t there always?” put in Karen.