Jorani's lips turned upward, as close to a real smile as his dour face could master. "Chemistry," he said. "The study of plants, of animals, of snakes, and of insects. There is my most treasured possession.

Be careful. Do not touch it."

Ilsabet peered into a blown-glass bubble hanging from one of the room's crossbeams, but it seemed to be filled with cobwebs, nothing more.

"Look closely," Jorani said.

Ilsabet did, squinting, finally making out the form of a tiny spider. It had spun its web so thickly that Ilsabet could hardly see it in the center of its container.

"Though the exit is uncovered, the spider is a lazy beast that has no inclination to leave the comfort of its home so long as I drop a fly into its web every day or so. No! Don't touch even the web, and don't put your face too close to the top of the bubble. It might think you are prey and attack."

As Ilsabet studied it, she had to admit it was a marvelous creature. Silver gray with white crisscross markings on its body and white bracelets at the end of each leg, it would practically disappear on a background of old wood or rotting fabric.

"It's the most dangerous specimen in this collection," Jorani told her. "A brush against its web will make a man ill. Put a pinch of the web in a man's food and he will have convulsions, mental confusion, fever. A bit more, and the victim falls into a coma and dies. Needless to say, the sting of the spider itself is lethal."

If it had moved in any way, Ilsabet would have fled the chamber in a moment. "Is there an antidote?"

"None, though it is believed that a person may build an immunity to the poison by touching or ingesting small pieces of the web. One of your ancestors experimented on prisoners with no success. They all died."

Ilsabet stared at the creature, so small, so retiring, its web gray like the fog that rose every night from the river.