But his hands were steady as he drew a sample of a few drops from the vaccine bottle. He lowered a wall panel and behind it there was a minute but astonishingly complete biological laboratory. It was designed for microanalysis--the quantitative and qualitative analysis of tiny quantities of matter. He swung out a miniaturized Challis fractionator. He inserted half a droplet of the supposed vaccine and plugged in the fractionator's power cable. It began to hum. The grid operator ground his teeth. "This is a fractionator," said Calhoun. "It spins a biological sample through a chromatograph gele." The small device hummed more shrilly. The sound rose in pitch until it was a whine, and then a whistle, and then went up above the highest pitch to which human ears are sensitive. Murgatroyd scratched at his ears and complained: "_Chee! Chee! Chee!_" "It won't be long," Calhoun assured him. He looked once at the grid operator and then looked away. There was sweat on the man's forehead. Calhoun said casually: "The substance that makes the vaccine do what it does do is in the vaccine, obviously. So the fractionator is separating the different substances that are mixed together." He added, "It doesn't look much like chromatography, but the principle's the same. It's an old, old trick!" It was, of course. That different dissolved substances can be separated by their different rates of diffusion through wetted powders and geles had been known since the early twentieth century, but was largely forgotten because not often needed. But the Med Service did not abandon processes solely because they were not new. Calhoun took another droplet of the vaccine and put it between two plates of glass, to spread out. He separated them and put them in a vacuum drier. "I'm not going to try an analysis," he observed. "It would be silly to try to do anything so complicated if I only need to identify something. Which I hope is all I do need!" He brought out an extremely small vacuum device. He cleaned the garments he'd just removed, drawing every particle of dust from them. The dust appeared in a transparent tube which was part of the machine. "I was sprayed with something I suspect the worst of," he added. "The spray left dust behind. I _think_ it made sure that anybody who left Government Center would surely be a para. It's another reason for haste." The grid operator ground his teeth again. He did not really hear Calhoun. He was deep in a private hell of shame and horror. The inside of the ship was quiet, but it was not tranquil. Calhoun worked calmly enough, but there were times when his inwards seemed to knot and cramp him, which was not the result of any infection or contagion or demoniac possession, but was reaction to thoughts of the imprisoned para in the laboratory. That man had gobbled the unspeakable because he could not help himself, but he was mad with rage and shame over what he had become. Calhoun could become like that--