Floating in the brilliant violet liquid that filled the crystal tube was a gray mass, wrinkled and corrugated. This was divided by deep clefts into right and left hemispheres, which, in turn were separated into larger upper and smaller lower segments. White filaments ran through the violet liquid from its base toward the three rings or bands of green metal that encircled the cylinder. In an instant, Larry realized that the gray mass was a human brain. The larger, upper part the cerebrum, the smaller mass at the back the cerebellum. And the white filaments were nerves, by means of which this brain controlled its astounding, mechanical body! A brain in a machine! The violet liquid, it came to Larry in his trance of wonder, must take the place of blood, feeding the brain-cells, absorbing waste. An eternal mind, within a machine! Free from the ills and weaknesses of the body. And devoid, too, of any pity, of any tender feelings. A cold and selfish mind, without emotion--unless it might worship itself or its mechanical body. It was this monster that had spilt the pool of blood drying on the floor, near the door. And it was these glistening, green, snake-like tentacles that had crumpled the revolver into a broken mass of steel! Abruptly the machine-monster darted forward, running swiftly upon its four legs of green metal. Slender tentacles reached out toward the shuddering girl at Larry's shoulder. "Run!" Agnes gasped to him, quickly. "It will kill you!" The girl tried to push him back. As she touched him, Larry recovered from his daze of wondering fear. Agnes was in frightful danger, and facing it with quiet courage. He must find a weapon! * * * * * Wildly, he looked about him. His eyes fell upon the tall, heavy wooden stool, upon which Agnes had been sitting. "Get back!" he shouted to her. He snatched up the stool, and, swinging it over his head, sprang toward the machine of violet-filled crystal and glittering green metal. "Stop!" Agnes screamed, in a terrified voice. "You can't--" She had run before him. He seized her arm and swung her back behind him. Then he advanced warily toward the machine-monster, which had paused and seemed to be regarding him with sinister intentness, through its glistening crystal eye-lenses. With all his strength, Larry struck at the crystal cylinder, swinging the stool like an ax. A slender, metallic green tentacle whipped out, tore the stool from his hands, and sent it crashing across the room, to splinter into fragments on the opposite wall. Larry, sent off his balance, staggered toward the glittering machine. As he stumbled against the transparent tube that contained the brain, he clenched his fist to strike futilely at it. A snake-like metal tentacle wrapped itself about him; he was hurled to the floor, to sprawl grotesquely among broken apparatus.