The guard hesitated. "Okay then. Make us do it the hard way," he said. They got in the car and drove off, Piggie making inarticulate sounds of protest and having to be dragged. Scat's eyes followed them. "Get out the truck," he told Len. "You're going to Manford to buy groceries. Click-Click, can your visitors. Fast." "Underground?" Len asked with a look. Scat nodded. About the time Len was ready to roll, the bug guards came jetting back, accompanied by a policeman who looked and acted exactly like them, except for the uniform. "Got a warrant to search your place for fugitive bugs," he told Scat. "Hold on there!" he called to Len, who was starting the truck. "Let's have a look before you get away." The bug guard led Piggie to the truck. She was making anxious, eager noises. Unexpectedly Click-Click came out from behind the truck, so that they almost collided. Piggie squealed and backed off, flapping her arms. The guard grabbed at his squirt gun, but Scat interposed. "Your bug done that on purpose," the guard blustered threateningly. "He knows Piggie's no good for as much as ten minutes after she gets that close to a bug." They searched the truck thoroughly. The body was empty except for some boxes of tape scrap and three medium sized cannisters conspicuously labeled in red: CAUTION! BEAM REFUSE GAS Standard Container Len's hand hovered over one of the cocks. "Want a sniff?" he asked pleasantly. The guard gave him a sour look. Beam refuse gas was so deadly a poison that it could not safely be disposed of by any ordinary methods. It had to be shipped to a reconditioning plant in containers that were seamless--supposedly. And these three cannisters actually contained beam refuse gas under standard pressure--they'd have to, in order to pass the minute inspection made at the regional border. But the shell of a Martian is one of the most impermeable armors ever developed by organic evolution, and when quiescent he can go upwards for an hour without breathing. This is because he is built for an extremely rarified atmosphere--his physiology is typical of a depleted-planet economy. On Mars his inhalation/exhalation ratio is about 100/1. The chief problem in acclimitizing him to Earth is teaching him to inhale as infrequently as he exhales--otherwise oxygen-drowning occurs. A Martian's lungs are really oxygen accumulators. He has 100 per cent utilization of inhaled oxygen, and he exhales pure carbon dioxide freighted with other respiratory excretions--hence the "bad breath" so obnoxious to human beings. * * * * *