“The Terries-Terrestrial Bureau of Investigation,” said Dr. Powell. He polished his panes unhappily.

“They cause more trouble than-” muttered the nurse.

“Still, best to take no chances. If the girl is in a bad way, it could cause trouble with the Spacers-there’s enough bad blood between us already.”

Derec thought swiftly, appalled. The “Terries” would find no record of them, would query whatever Spacer representation there might be on Earth, find no record there, and the reactor would flash over. But he couldn’t think of a thing to say.

“Look-”

Ariel moaned and turned partly on her side; only the straps kept her from falling. If she’d been listening, she couldn’t have timed it better. All three Earthers leaped to her, and Derec pocketed the ID tag the nurse had put down.

He thought quickly. The doctors were concerned and totally focused on Ariel. Derec looked around. As he recalled R. David’s work, the ID tag merely gave name and ID workup. Not address. Medical care was on an as-needed basis, not rationed, so nobody cared about place of residence, and in fact they hadn’t been required to enter that. (Or was that because Ariel’s tag gave her rating as Transient? He needed to know a lot more about Earth.)

In any case, he thought, the only thing they knew about Ariel was what the computer recorded from the ID tag.

Leaving them working over her, he slipped out and strolled around, speaking to no one, trying to look like a worried, expectant father pretending to be nonchalant. A couple of people looked at him sympathetically, but most didn’t seem to notice him at all, for which he was grateful.

There it was. An office. He slipped in, looked at the terminal. It was probably dedicated to a single function, but he could try. He had watched R. David coding ID tags of a dozen kinds, and had a good grasp of what was implied. And frankly, these computers were simple after programming positronic brains and restructuring the programming of the central computer of Robot City. It took him a mere half hour to get through the programming, retrieve the record on Ariel, and erase it.

Now let’s hope there isn’t a backup memory somewhere,he thought gloomily.

They caught up with him in the interior waiting room, standing aimlessly about and unobstrusively slipping toward the outer waiting room, where he supposed he belonged.

“There you are,” said the nurse. For the first time, he noted that her jacket had a name label imprinted Korolenko, J. “Why didn’t you wait in the Friends’ Lounge?”

He didn’t bother to tell her they hadn’t shown him to it. “Had to go to the Personal,” he said, not knowing if Earthers could mention the Personal so openly.

She got ideas, frowned, put something warm from her pocket against his head. Apparently his temperature was all right. “Very well. But come in here. The doctors will need to speak to you.”

Within ten minutes Dr. Li entered the room briskly, sat down, exhaled heavily. “She had us worried, but it was mostly exhaustion of the body’s resources. Starvation, to put it crudely. She must have been going on nerves and caffeine for weeks.”

“She hasn’t been eating well,” Derec admitted. He’d been blind not to see how little she’d been eating. “What does she have?”

“We’ll know for sure in a day; we’ve done a culture. But our best guess is amnemonic plague.”

“Ay…nuhmonic…?”

“From medieval mnemonic, meaning memory. Amnemonic means no memory. It’s a mutation of an old influenza virus, first reported on one of the Settler worlds-sometimes called Burundi’s Fever, after the discoverer.” She looked at him sharply, but clearly that name meant no more to Derec than the first.

“Will she-get better?”

Dr Li sighed. “When Burundi ‘s crosses the blood-brain barrier, it isn’t good. We’re giving her support-nourishment and so on-and antibiotics that eventually will cure the disease. Our anti-virals are fairly effective, except where the virus has crossed the blood-brain barrier. Antibodies will help a little,” and we’re administering them. We’ll be able to stop the infection in all but her brain within a day or two.”

Derec had the illusion that his chest had turned into a block of wood. His heart pushed once, hard, against its unyielding surroundings, and gave up. He felt it stop moving. “Her…brain?”

Dr. Li sighed and looked four hundred years old. “There’s hope. It’s by no means over. I do wish we’d gotten at her sooner…Well, try not to feel guilty; and I’m sorry if I made you feel worse. You couldn’t have known. All kids are heedless, think they’ll live forever…” She brooded on her capable hands for a moment. “Then you think she’ll live?”

“Let’s say, I have a good hope of it. Saul-Dr. Morovan -is a specialist on viruses and has treated amnemonic plague three times, twice successfully-and the third time was a patient whose disease had advanced much farther than your wife’s.”

Derec suspected that the symptoms of the other two had been much less advanced than Ariel’s, but said nothing. It was something, he acknowledged, that they knew the disease, had a cure for it, and had hope for her. Of course, he thought, we were fools-chauvinistic fools-to assume that the Spacer worlds were the only ones that knew anything about medicine. Who but Earth, incubator of virtually every disease known to mankind, would know more about medicine? Among the Spacer worlds, he supposed, amnemonic plague was invariably fatal when it crossed the blood-brain barrier…

Derec felt his knees shaking and was glad he wasn’t standing.

“What?” He’d missed some of what she’d been saying.

“Need a sample,” she repeated. “We can’t give you the vaccine if you have the disease, at least in its later stages.”

The Key to Perihelion affected the stomach like this: a sudden drop as one went from gravity to free-fall instantly. Derec nearly threw up. Gulping, he said, “Y-yes, Ma’am,” and held out his arm.

Disease!

The possibility had always been there, associating with Ariel. But it was obvious that what she had wasn’t easily contagious. She had only mentioned once, more or less directly, howshe had contracted her illness, as a warning to him. But that was the only time they had come close to more than accidental physical contact. Now that he thought about it, she had kept her distance, even when she had clearly wanted and needed to be hugged. His Spacer’s horror of disease had not been as greatly allayed as he had thought, he realized, shaky. The prophylactic treatment R. David had given them had reassured him, Ariel’s attitude and his worry over her had reassured him, and the heedlessness of youth…

His eyes must have mirrored some of his horror, for Dr. Li looked at him sharply and said, “Don’t worry! You’re obviously in a very early stage, if you have it at all. And we’re going to give you a thorough going-over, to make sure you aren’t coming down with something else.”

They did that for the next half hour. The Human Medical Team would have been faster. but no less thorough. he thought.

“Good, you’re totally free of disease, so far as we can tell,” said Dr. Powell. “Fortunately, your intestinal microorganisms are not markedly different from the Terrestrial strains, and there’s as yet nothing else to worry about. Dr. Li, the vaccine…”

“Incidentally, we detected antitoxins to Burundi’s in your system,” said Dr. Li. “You may have had a mild case of the fever earlier; it may even still be latent in your system. However, the vaccine will immunize you totally.”

“Uh-” said Derec, as a thought took him. “Have I been a carrier all this time?”

Uneasily, he visualized Ariel and himself spreading disease all over Rockliffe Station, where they had crashlanded after escaping the pirate Aranimas. Any human who subsequently entered the station might contract the disease