Under the mask, the face had a perfectly natural look. The features were relaxed and vacuous, but there was no flowing, no unnatural distortion at all. And it was quite a different face--the face of a man who had worn a disguise and was now so completely a stranger to Corriston that he might just as well have been any one of the Station's thirty-seven Security Guards. Corriston could see where the hook attachments had gone into the flesh in at least thirty places on the man's face: on his brow, his cheekbones, on both sides of his face clear down to the base of his neck. The tiny punctures made by the hooks were faintly rimmed with blood, perhaps because Corriston had torn the mask away too abruptly. Undoubtedly the skin had been anaesthetized, the hooks inserted skillfully by someone familiar with just what should be done to prevent scarring. He hoped that the guard would not carry tiny scars on his face for the rest of his natural life. He arose and examined the mask. He had a complete false face. The thing was ingenious beyond belief. It was no mere Halloween assemblage of papier-maché flimflammery, but an elaborate and flexible mask of very thin plastic, or possibly metal. A prosthetic mask--if one could use that term in connection with a mask. It was certainly more complex in structure than any prosthetic leg or arm he had ever seen on a handicapped man, or would ever be likely to see. He had a pretty good idea as to how it worked. A general idea. Apparently when the hooks were attached to the muscular structure of the human face underneath, every aspect of the wearer's face would be instantly controlled and altered to conform to the configuration of the false face. In that sense the mask could be said to actually mold itself to the wearer's face and transform it into a completely new and different face. And yet, in some subtle way, the emotions felt by the owner of the real face would be conveyed to the mask, so that it would express with different features very much the same kinds of emotion. Ingenious was scarcely the word for it. It was a miracle of technological science, almost beyond belief. But he could not doubt the reality of what he saw, for he held the evidence in his hand. No hallucination could possibly be _that_ real. The way the mask's surface coloration could change when the wearer's emotions changed was perhaps the most amazing miracle of all. He had seen the guard's color come and go, had watched him redden with anger and then grow pale.