The little motor purred briskly. The plastic rods turned against fur brushes, while a wiper cleared off any dust they picked up. There was no dust he could see; the traps had done their work. Some plant irritant, like poison ivy? No, he'd always worn his suit--Mars had an atmosphere, but it wasn't anything a man could breathe long. The suit was put on and off with automatic machine grapples, so he couldn't have touched it. The rash seemed to get worse on his body as he looked at it. This time, he tore one of the tissues in quarters as he sneezed. The little supply was almost gone; there was never space enough for much beyond essentials in a spaceship, even with the new atomic drive. As he looked for spots, the burning in his nose seemed to increase. He dropped back to the pilot seat, cursing. Two months of being cramped up in this cubicle, sweating out the trip to Mars without knowing how the new engine would last; three weeks on Mars, mapping frantically to cover all the territory he could, and planting little flags a hundred miles apart; now a week on the trip back at high acceleration most of the way--and this! He'd expected adventure of some kind. Mars, though, had proved as interesting as a sandpile, and even the "canals" had proved to be only mineral striations, invisible from the ground. He looked for something to do, but found nothing. He'd developed his films the day before, after carefully cleaning the static traps and making sure the air was dust-free. He'd written up the accounts. And he'd been coasting along on the hope of getting home to a bath, a beer, and a few bull sessions, before he began to capitalize on being the first man to reach another planet beyond the Moon. He cut on full acceleration again, more certain of his motors than of himself. He'd begun to notice the itching yesterday; today he was breaking out in the rash. How long would whatever was coming take? Good God, he might die--from something as humiliating and undramatic as this! It hadn't hit him before, fully. There was no knowing about diseases from other planets. Men had developed immunity to the germs found on Earth; but just as smallpox had proved so fatal to the Indians and syphilis to Europe when they first hit, there was no telling how wildly this might progress. It might go away in a day, or it might kill him just as quickly. He was figuring his new orbit on a tiny calculator. In two days at this acceleration, he could reach radar-distance of Earth; in four, he could land. The tubes might burn out in continuous firing. But the other way, he'd be two weeks making a landing, and most diseases he could remember seemed faster than that. Bill wiped the sweat off his forehead, scratched at other places that were itching, and stared down at the small disk of Earth. There were doctors there--and, brother, he'd need them fast!