Jon Akars, petty officer of the Sun Line freighter Cinnabar , backed away from the jimmied manifold of the air circulators and hastily felt for the emergency mask at his belt. Any moment now the Venusian kui-knor he had filched from the ship's medicine cabinet and dropped into the circulators would take effect. Without warning men would drop at their posts, apparently insensible, rigid of muscle, eyes staring fixedly. Actually, they would be keenly aware of everything about them, their senses sh