The black-masked figure dipped the nozzle of the thing into the tub and worked a plunger, then turned to the struggling life-form shackled to the altar. Deftly, he stabbed the snout of the tool into a spot below the creature's breast-bone. The captive tried to jerk away, to no avail. With smooth precision, the primitive in black pressed home the plunger. A gusty sigh ran through the throng about the platform. It came to Jarl that he was cold as ice despite the heat and blazing sun. The musty, sweetish smell he'd caught before swirled about him, even stronger. The black-masked figure straightened. With quick, sure movements, he twisted at a fitting, then lifted away the tool. The nozzle he left sticking in the creature on the altar. It thrust up from the hollow below the breast-bone like the hilt of a deep-plunged dagger. The two primitives by the wheeled tub let the lid fall back. Turning, one darted to the bulkhead door. When he came out, he bore a flaring torch. New silence fell upon the crowd, so complete that the altar-crewman's footsteps rang and echoed in the stillness. He passed the torch to his black-masked fellow. Black-Mask swung the flaming brand on high and, turning, faced Jarl Corvett. His voice thundered, harsh and guttural. Jarl stood rock-rigid. The words he could not understand. But the threat, the menace--they needed no translator. * * * * * Pivoting, the primitive stepped back from the altar; thrust out the torch till its flame touched the tip of the nozzle protruding out of the shackled prisoner's chest. Of a sudden Jarl's whole body was drenched with icy sweat. He could not move; he could not breathe. The tales of horror he'd heard so many times swirled through his brain. For an instant, nothing happened. Then, all at once, there was a puff of sound, a flash of flame above the captive. A great black jet of smoke shot high into the air, out of the nozzle. The life-form on the altar gave one shrill cry that was agony, incarnate. Its body jerked and twisted, lashing against the shackles in a frenzy. The primitives went mad. The huge room rocked with their howls and screamings. But Jarl Corvett hardly heard them. He'd seen cruel death before, on a dozen far-flung planets. But this.... For while he watched, thin lines of fire were racing along the doomed sacrifice's writhing body. In a spreading network, the flesh itself was bursting open, flames leaping up in a thousand places. In a searing flash, the truth came to Jarl: _The creature's blood was burning!_ He sagged in his escort's grip, and retched--shock-stunned, sick with horror. But the primitives who flanked him jerked him upright. An open hand stung his face with brutal slaps. The spell that gripped Jarl broke. Numb, tight-jawed, he forced himself to look again upon the altar. The shackled creature lay there still, a charred, contorted horror.