"When you think about it," Leavitt said, "we've faced up to quite a planning problem here. How to disinfect the human body—one of the dirtiest things in the known universe—without killing the person at the same time. Interesting.

He wandered off. Dripping wet from the shower, Hall looked around for a towel but found none. He entered the next room and blowers turned on from the ceiling in a rush of hot air. From the sides of the room, UV lights clicked on, bathing the room in an intense purple light. He stood there until a buzzer sounded, and the dryers turned off. His skin tingled slightly as he entered the last room, which contained clothing. They were not jumpsuits, but rather like surgical uniforms—light-yellow, a loose-fitting top with a V-neck and short sleeves; elastic banded pants; low rubber-soled shoes, quite comfortable, like ballet slippers.

The cloth was soft, some kind of synthetic. He dressed and stepped with the others through a door marked EXIT TO LEVEL II. He entered the elevator and waited as it descended.

Hall emerged to find himself in a corridor. The was here were painted yellow, not red as they had been on Level I. The people wore yellow uniforms. A nurse by the elevator said, "The time is 2:47 p.m., gentlemen. You may continue your descent in one hour."

They went to a small room marked INTERIM CONFINEMENT. It contained a half-dozen couches with plastic disposable covers over them.

Stone said, "Better relax. Sleep if you can. We'll need all the rest we can get before Level V." He walked over to Hall. "How did you find the decontamination procedure?"

"Interesting," Hall said. "You could sell it to the Swedes and make a fortune. But somehow I expected something more rigorous."

"Just wait," Stone said. "It gets tougher as you go. Physicals on Levels III and IV. Afterward there will be a brief conference."

Then Stone lay down on one of the couches and fell instantly asleep. It was a trick he had learned years before, when he had been conducting experiments around the clock. He learned to squeeze in an hour here, two hours there. He found it useful.

The second decontamination procedure was similar to the first. Hall's yellow clothing, though he had worn it just an hour, was incinerated.

"Isn't that rather wasteful?" he asked Burton.

Burton shrugged. "It's paper."

"Paper? That cloth?"

Burton shook his head. "Not cloth. Paper. New process."

They stepped into the first total-immersion pool. Instructions on the wall told Hall to keep his eyes open under water. Total immersion, he soon discovered, was guaranteed by the simple device of making the connection between the first room and the second an underwater passage. Swimming through, he felt a slight burning of his eyes, but nothing bad.

The second room contained a row of six boxes, glass-walled, looking rather like telephone booths. Hall approached one and saw a sign that said, "Enter and close both eyes. Hold arms slightly away from body and stand with feet one foot apart. Do not open eyes until buzzer sounds. BLINDNESS MAY RESULT FROM EXPOSURE TO LONG-WAVE RADIATION."