His nerves tingled at the eerie thing that was happening there. He didn't know whether to feel afraid of it or hopeful. Man was stumbling toward ultimate mastery of his own flesh and the forces of the universe. But the distance remained enormous, though technical science was moving forward, perhaps too swiftly, on all fronts. Part of Ed's fear before the unknown was like the stage fright of an inexperienced actor. You never quite knew what was ahead or how to judge anything strange that you saw. "_Nippe...._" At the end of the line which made the "e" there was a tiny speck of blue ink. Almost imperceptibly, like the minute hand of a clock, it crept on, curving and looping to form another letter. "_Nipper_" the word was now. This could be somebody's funny gag, Ed thought. Somebody with a gadget. The world is full of gadgets these days. Maybe too full. It occurred to him that a pal might be playing a joke with some simple device bought in a novelty store. But probability leaned toward something deeper and more costly. Who knew? Someone might have invented a way to make a man invisible. You didn't deny that anything could be, any more. "Speak up!" he ordered softly. But no answer came, and his wondering gaze found nothing unusual in the room around him. He froze. "_Nipper._" It could be part of a message, an honest attempt to convey vitally important information. Or it could be the forerunner of violence aimed in his direction. Through no fault of his own, he had had enemies for ten years. Tonight they might really act. To die was still possible. In spite of vitaplasm. Or the more tedious method that employed natural flesh. Or the tiny cylinders hidden away in vaults. Lives were now in danger again. Human, and almost human.... For a moment Ed wanted to give a warning and to call others into consultation. He wanted to shout, "Dad! Mom! Come here!" He didn't do so. Between him and the precise, benign personality that he called Dad there was a gradually growing barrier. And for his mother, beautiful and young by art and science, he had that feeling of male protectiveness that takes the form of keeping possible dangers hidden. Ed decided to work on his own. Being essentially careful and slow moving when it came to delicate processes, he had not touched that creeping droplet of ink. Its secret might thus be destroyed. No, he'd never do a thing so foolish. Swiftly he folded the paper and fastened the writing under his microscope. The ink speck was almost dry now, and nothing was hidden in it. The line of the writing itself was odd under magnification. Here and there it showed tiny, irregular dots at spaced intervals, connected by fine, dragging marks. That was all. Of course he realized that _Nipper_ might be only the first cryptic word of a message and that he had only to wait and see what would follow. Until he began to wait, however, the significance of the word itself eluded him. A child's nickname was all that it suggested.