"Dondara!" he shouted in elation. "Dondara--it responds!" He ran out of the dome, and came back pulling a girl by the hand. And I knew, through the wonder of that perception, that she was Dondara Keradin, the gifted research assistant of this man, and his dearly beloved. But a blade of agony cleft my heart. For her slim beauty was terribly familiar. Her dark hair had that glint of red I knew so well, and her eyes were the true violet I had seen only in my dead wife, and in that crystal vision. She _was_ Dona Carridan, and the woman in the crystal! * * * * * A bright flame of hope burned at my old skepticism of reincarnation. Was Dona born again? Had I slept these thousand centuries to find her? A weary despair quenched that hope. For if she had been reborn, so had I, in this eager experimenter beside her. "Come, Dondara, darling!" Bari Horn was gasping. "All the others were mere machines. But this responds--_intelligently_! Watch the needle. It spells a message--a request for different food-chemicals!" The lovely girl looked unwillingly at the black, faintly quivering mass in the crystal vessel. A slow horror widened and glazed her eyes. "I don't like it, Bari," she whispered. "It's--_bestial_!" "The others were," said the flushed experimenter. "But this is an actual brain. Its cells and fibers are of metal colloids, sheathed in synthetic myelin. A robot brain--finer and quicker than a man's!" Her face was white. "I don't like it," she insisted. "Why make a mechanical brain better than a man's, Bari--when the brains of men have already done so much?" "Because there is so much yet to be done," Bari Horn told her. "Men have no more than explored the Galaxy--Nature is not yet and perhaps never will be fully conquered. My robot technomatons will be a powerful ally. "A man's brain is stupid. It learns slowly and with effort. It fumbles. It is clogged or diverted with emotion. It forgets. And finally, when it has acquired a little learning and a little skill, it dies altogether. "But this brain--I'm going to name it Malgarth, from the first letters the needle spelled out--is quick. No emotion will disturb its delicate processes. It will never tire, never forget--never die! Barring accident, it can survive a million years, always growing, gaining knowledge, solving problems that would baffle a whole race of men. It will be itself a library and museum of all knowledge, stored up to aid mankind. "There are fine machines, already. Now my robot brains can tend them, and men will be set free." "Free?" The girl stared at him, a horror in her eyes. "Or enslaved--to your robots?" She pointed at the black, pulsating mass in the beaker. "It often seems to me, Bari," she breathed, "that man is already the slave of his machines! He toils to build them, to repair them, to find fuel for them. Now, if you put a brain in a space ship, will it not think of men merely as servants, transported that they might care for it?"