Then he undressed down to his underwear, turned out the light and lay on the narrow iron bed. John rustled in his cage for a minute, then there was only the faint hum of the blower and sucker motors in the ventilating system. The incoming and outgoing air was baffled and trapped to kill sounds, and spring-loaded sliding doors poised to jam shut and seal off the room if anyone tampered with the exterior grilles in the roof. The fans hummed softly and Erd Neff slept. _Sleck-thud, sleck-thud!_ * * * * * He was awake pawing the wall for the light switch, but even as his hand found it, and his eyes discovered the closed ventilator doors, a reddish vapor sank over his body. A single gasp and Neff was clawing his throat. Sharp, brown-tasting, acid-burning, eye-searing, nose-stinging! He fell to his knees and clawed to the far corner, fighting for air, but the acrid stink stained his throat and nose. His eyes kept burning. The whole room must be full! The door-lever! No, that's what they wanted. Blind! Gun's no good now. God, for a breath of air! Damned tears! Can't open my eyes! Air! _Got to have it!_ His throat refused to open. The stink, a little like iodine, a lot like a hospital smell but a million times stronger--raked at the tender tissues of his throat. Icepicks stabbed from his soft palate, up into his brain, his temples. He swayed against the door, caught the lever and heaved convulsively. The door fell away slowly. He stumbled forward, gashing his knee against the sharp jamb. A light struck redly through his clenched, tear-soaked eye-lids. "That did it. Get the gun!" The voice was high, almost girlish. A young boy? A slightly heavier voice said, "Got it. Keep an eye on him while I find out why the fan stopped working." "He's going no place. You were right. That bromine stuff really did the business. Lookit his face. Sure it won't kill him?" "Don't care if it does now. We got the door open." "What is this bromine, anyhow? Boy it sure stinks!" "It's a chemical element like chlorine, only it's a liquid. It fumes if you don't keep it covered with water, and the fumes really get you. They used it in gas bombs in the war." "That was chlorine." "They used bromine, too. I read it." "Air!" Neff rasped. "Help yourself if you call this stinkin' stuff in your warehouse air." From the vault the deadened voice came. "This must be the switch. The other switch is for the lights." "Look out! When you turn it on don't get dosed yourself." "I only dumped a few drops in. There. It'll blow out in a few--phew, let me outta here. That stuff does--God, it's worse than the dose I got in the chem lab!" The voice grew, coughing and cursing. "Better wait a minute or two. How's our big brave dog-killer doing?" On his hands and knees, Neff was on the verge of passing out, but doggedly he tried to place the voices. Highschool kids? _Bromine._ Sounded like a chemical they might filch from the highschool laboratory.