He offered the blaster. Calhoun jumped when he saw it in Murgatroyd's paw. The blaster jerked, and Murgatroyd's paw tightened to hold it. He pulled the trigger. A blaster-bolt crashed out of the barrel. It was a miniature bolt of ball-lightning. It went into the floor, vaporizing the surface and carbonizing the multi-ply wood layer beneath it. The Med Ship suddenly reeked of wood smoke and surfacer. Murgatroyd fled in panic to his cubbyhole and cowered in its farthest corner. But there was a singular silence in the Med Ship. Calhoun's expression was startled; amazed. He was speechless for long seconds. Then he said blankly: "Damnation! How much of a fool can a man make of himself when he works at it? Do you smell that?" He shot the question at the grid operator. "Do you smell that? It's wood smoke! Did you know it?" Murgatroyd listened fearfully, blinking. "Wood smoke!" said Calhoun between his teeth. "And I didn't see it! Men have had fires for two million years and electricity for half a thousand. For two million years there was no man or woman or child who went a full day without breathing in some wood smoke! And I didn't realize that it was so normal a part of human environment that it was a necessary one!" There was a crash. Calhoun had smashed a chair. It was an oddity because it was make of wood. Calhoun had owned it because it was odd. Now he smashed it to splinters and piled them up and flung blaster-bolt after blaster-bolt into the heap. The air inside the Med Ship grew pungent; stinging; strangling. Murgatroyd sneezed. Calhoun coughed. The grid operator seemed about to choke. But in the white fog Calhoun cried exultantly: "Aromatic olefines! Acetone! Acetic acid radicals and methyl submolecular groups! And smoke has unsaturated hydrocarbon gases. This is the stuff our ancestors have breathed in tiny quantities for a hundred thousand generations! Of course it was essential to them! And to us! It was a part of their environment, so they had to have a use for it! And it controlled the population of certain molecules...." The air system gradually cleared away the smoke, but the Med Ship still reeked of wood-smoke smells. "Let's check on this thing!" snapped Calhoun. "Murgatroyd!" * * * * * Murgatroyd came timidly to the door of his cubbyhole. He blinked imploringly at Calhoun. At a repeated command he came unhappily to his master. Calhoun petted him. Then he opened the chest in which a container held living scavengers which writhed and swam and seemed to seethe. He took out that container. He took off the lid. Murgatroyd backed away. His expression was ludicrous. There was no question but that his nose was grievously offended. Calhoun turned to the grid operator. He extended the sample of scavengers. The grid man clenched his teeth and took it. Then his face worked. He thrust it back into Calhoun's hand.