"Four weeks ago," said Haroche. "At the all-departments briefing."

"About a week before that, actually," said Miles. "According to my informant."

Haroche gave him a sharp look. "Really."

Illyan stirred, as if about to add something, but then kept his peace.

"Hm. The prokaryote does not reproduce very rapidly. Much depends on how large a dose was initially introduced."

"Yes, and how was it done?" Miles put in. "For that matter, how is this stuff stored and transported? What's its shelf life? Does it require any special conditions?"

"It's stored dry, in an encapsulated form, at room temperature, though it would not be harmed by mild freezing. Shelf life—heavens. Years. Though it's obviously less than a decade old. It is activated by wetting, presumably upon administration, which requires moist contact. Through mucous membranes—it could have been inhaled as a dust—injected as a solution, or introduced as a contaminant into a scratch. Broken skin and moisture would do it. It wouldn't have to be a large scratch."

"Swallowed?"

"Most of the prokaryotes would be destroyed by stomach acids. It could be done, but would require a larger initial dose, to be certain enough entered the bloodstream to be carried to the chip."

"So . . . when? What's the maximum possible time-window for exposure? Can't you use its reproductive rate to calculate when it was administered?"

"Only crudely. That's one of the several variables, I'm afraid, my lord. Administration must have been between ten weeks and one week before the appearance of the first symptoms."

Miles turned to Illyan. "Can you remember anything like that?"

Illyan shook his head helplessly.

Haroche said, "Is there any way . . . could it . . . is it possible the exposure might have been accidental?"

Weddell screwed up his mouth. "Possible? Who can say? Likely? That's the question." And he looked as if he was glad he didn't have to answer it.

"Have there been"—Miles turned to Haroche—"any reports of anyone else on Barrayar who possesses related chip technologies undergoing a mysterious breakdown?" For that matter, did anyone else on Barrayar possess a related chip?

"Not that I know of," said Haroche.

"I would like ImpSec to double-check that, please."

"Yes, my lord." Haroche made a note.

"The jump-pilots' neural implants use an altogether different system," put in Avakli. "Thank God." He blinked, presumably at an inner vision of the chaos that would result from some sort of pilot-plague.

"This prokaryote is not communicable by ordinary means," Weddell assured them, rather offhandedly, Miles thought.

"We must assume a worst-case scenario, I think," said Miles.

"Indeed," sighed Haroche.