artificial nature of his memory blocks and trace them to their source. A battery of electronic brains has more efficiency than emotion. Even primed as he was by a visit to the outlawed auto-hypnotic devices hidden in the old native quarter of Castarona, there was no real chance of deceiving the robot brains. He did not expect that, but he did hope to confuse the issue long enough, cause enough delay, to give him his one chance of escape. His plan was carefully worked out. Not foolproof, but a matter of extremely delicate timing. It could work. But now....

By a supreme effort, he tried to banish all thought of escape from his thought-patterns, tried to smudge out the record of all recent emotion, tried to forget everything that had happened to him in the Tihar Forest. Especially....

At first Alston answered in words, speaking aloud from habit. Vocal response was not required, meant nothing to the machine. The sounds were noted and filed for future reference. Precise brain-wave pattern measurements and analysis of physiological reactions combined into far more exact information about him than any word or thought formed consciously by the subject. The robot psychograph was a lie detector, encephalograph, and electronic calculator. Its prying fingers reached into the human soul and came forth with stark truth.

Sharp, incisive, implacable, the psychograph probed with its mechanical voice. Alston responded, his mind dulling, drifting on the vagaries of memory stream, lulled by the drone of heating tubes, the rustling hiss of his own breathing, the click of relays. Naked danger lay in this state for Alston, yet he dared not brace himself against the questioning. Synthetic memories would serve better if he yielded to his subconscious. His voice descended to wordless mumbling, then died away in cushioned silence.

Above all, no thought of escape, of dying or disappearance.

Alston was no different from other men except for the dogtag. He was cast in the same mold of common humanity, but the identification dogtag fastened on an impervium wire round his neck made the difference.

A man with the VE convict dogtag broadcasting its invisible and inaudible signal cannot escape, cannot merely disappear. At any time, wherever he was, its signal could be tuned in and his exact position located. If the tag were forcibly removed by breaking the wire, almost an impossibility with impervium, the signal automatically became an alarm to summon patrol fliers from Castarona or Quanta City. The escapee would be picked up within a 

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