A prosperous Philadelphia plumber, a man of exemplary habits and seemingly in good health, left his home one day to take a short walk. From that moment he disappeared as completely as though the earth had opened and swallowed him. There was no reason why he should abscond or commit suicide, and the general belief was that he had met with foul play. Rewards were offered, and detectives employed, but no trace of him could be found. His wife, giving him up for dead, sold his business and removed with their children to Chicago. Nearly two years later, the workmen in a tin-shop in a Southern city were startled one morning by the conduct of one of their number, who, dropping his tools and pressing his hand to his head in a bewildered way, sprang to his feet, and cried: "My God! Where am I? How did I get here? This isn't my shop!" The foreman, thinking he was drunk, or had gone insane, ran forward to pacify him. "Steady, Smith, steady!" he exclaimed. "You'll be all right in a minute." The other only stared at him wildly. "Why do you call me Smith?" he demanded. "That isn't my name." "That's the name you've gone by since you came among us six months ago." "Six months ago! You're crazy, man. It isn't half an hour since I left my wife and little ones to get a breath of fresh air before dinner." "Look here," said the foreman, pressing him gently into a seat, "where do you suppose you are, anyway?" "Why, in Philadelphia, of course." It was indeed the Philadelphia plumber, whose missing self had returned to him as suddenly and as mysteriously as it had vanished. A few days more and he was happily reunited with the family that had so long believed him to be among the dead.[46] [46] Boris Sidis's "Multiple Personality," pp. 365-368. This book, by one of the foremost American psychopathologists, should be read by all students of abnormal psychology. Where, it may well be asked, was this man's original self during these two years? What had become of his normal ego, the ego of which alone he had formerly been aware? Yet at no time throughout the period when he lacked knowledge of his identity, and was without memory for his earlier life and social relationships, did he display the slightest sign of mental aberration. He was as sane and real to himself and to those with whom he came into contact, and was as able to take care of himself and earn a sufficient living, as he had ever been in the years before he experienced the remarkable psychical upheaval that had substituted an alien, a "secondary" self in the place of the self he had always been and known.