Calhoun's hands clenched. Automatically, he moved toward the other still figure, to act as a medical man does when somebody is hurt. The grid operator seized his arm. As Calhoun jerked to get free, that second man stirred His blaster lifted and rasped. The little pellet of ball-lightning grazed Calhoun's side, burning away his uniform down to the skin, just as there was a grating roar of blaster fire. The second man died. "Are you crazy?" demanded the grid operator angrily. "He was a para! He was here to try to kill you!" The police head snapped: "Get that car sprayed! See if it had equipment to spread contagion! Spray everything it went near! And hurry!" There was silence as men came from the spaceport building. They pushed a tank on wheels before them. It had a hose and a nozzle attached to it. They began to use the hose to make a thick, foglike, heavy mist which clung to the ground and lingered there. The spray had the biting smell of phenol. "What's going on here?" demanded Calhoun angrily. "Damnation! What's going on here?" The Minister for Health said unhappily: "Why ... we've a public-health situation we haven't been able to meet. It appears to be an epidemic of ... of ... we're not sure what, but it looks like demoniac possession." II "I'd like," said Calhoun, "a definition. Just what do you mean by a para?" Murgatroyd echoed his tone in an indignant, "_Chee-chee!_" This was twenty minutes later. Calhoun had gone back into the Med Ship and treated the blaster burn on his side. He'd changed his clothing from the scorched uniform to civilian garb. It would not look eccentric here. Men's ordinary garments were extremely similar all over the galaxy. Women's clothes were something else. Now he and Murgatroyd rode in a ground car with four armed men of the planetary police, plus the civilian who'd been introduced as the Minister for Health for the planet. The car sped briskly toward the spaceport gate. Masses of thick gray fog still clung to the ground where the would-be assassins' car lay on its back and where the bodies of the two dead men remained. The mist was being spread everywhere--everywhere the men had touched ground or where their car had run. Calhoun had some experience with epidemics and emergency measures for destroying contagion. He had more confidence in the primitive sanitary value of fire. It worked, no matter how ancient the process of burning things might be. But very many human beings, these days, never saw a naked flame unless in a science class at school, where it might be shown as a spectacularly rapid reaction of oxidation. But people used electricity for heat and light and power. Mankind had moved out of the age of fire. So here on Tallien it seemed inevitable that infective material should be sprayed with antiseptics instead of simply set ablaze. "What," repeated Calhoun doggedly, "is a para?" The Health Minister said unhappily: