He was quick on the draw, but Bull had his gun already out. The bullet thundered against Tex's skull. The world exploded into fiery darkness, through which he heard Breska say, "Sure, Bull. Why should I stay here to die for nothing?" Tex tried to cry out, but the blackness drowned him. He came to lying on the catwalk. His head was bandaged. Frowning, he opened his eyes, blinking against the pain. Breska hunched over the nearest gun, whistling softly through his teeth. "The Lone Prairee." Tex stared incredulously. "I--I thought you'd gone with the others." Breska grinned. "I just wasn't as dumb as you. I hung behind till they were all outside, and then I barred the door. I'd seen you weren't dead, and--well, this cough's got me anyway, and I hate forced marches. They give me blisters." They grinned at each other. Tex said, "We're a couple of damn fools, but I reckon we're stuck with it. Okay. Let's see how long we can fool 'em." He got up, gingerly. "The Skipper had some books in his quarters. Maybe one of 'em would tell what this dry stuff is." Breska coughed and nodded. "I'll keep watch." Tex's throat burned, but he was afraid to drink. If the water evaporated in his mouth as it had in Kuna's.... He had to try. Not knowing was worse than knowing. A second later he stood with an empty cup in his hand, fighting down panic. Half the water had vanished before he got the cup to his mouth. The rest never touched his tongue. Yet there was nothing to see, nothing to feel. Nothing but dryness. He turned and ran for Captain Smith's quarters. Hertford's _Jungles of Jupiter_, the most comprehensive work on a subject still almost unknown, lay between Kelland's _Field Tactics_ and _Alice in Wonderland_. Tex took it down, leafing through it as he climbed to the parapet. "Here it is," he said suddenly. "'Dry Spots. These are fairly common phenomena in certain parts of the swamplands. Seemingly Nature's method for preserving the free oxygen balance in the atmosphere, colonies of ultra-microscopic animalcules spring up, spreading apparently from spores carried by animals which blunder into the dry areas. "'These animalcules attach themselves to hosts, inanimate or otherwise, and absorb all water vapor or still water nearby, utilizing the hydrogen in some way not yet determined, and liberating free oxygen. They become dormant during the rainy season, apparently unable to cope with running water. They expand only within definite limits, and the life of each colony runs about three weeks, after which it vanishes.'" "The rains start in about a week," said Breska. "Our relief can't get here under nine days. They can pick us off with snakes and beetle-bombs, or let us go crazy with thirst, let the first shower clear out the ani--the whatyoucallits, and move in. Then they can slaughter our boys when they come up, and have the whole of Jupiter clear."