I have told elsewhere of my first acquaintance with Martin Hewitt, of his pleasant and companionable nature, his ordinary height, his stoutness, his round, smiling face--those characteristics that aided him so well in his business of investigator, so unlike was his appearance and manner to that of the private detective of the ordinary person's imagination. Therefore I need only remind my readers that my bachelor chambers were, during most of my acquaintance with Hewitt, in the old building near the Strand, in which Hewitt's office stood at the top of the first flight of stairs; where the plain ground-glass of the door bore as inscription the single word "Hewitt," and the sharp lad, Kerrett, first received visitors in the outer office. Next door to this old house, at the time I am to speak of, a much newer building stood, especially built for letting out in offices. It happened that one day as Hewitt left his office for a late lunch, he became aware of a pallid and agitated Jew who was pervading the front door of this adjoining building. The man exhibited every sign of nervous expectancy, staring this way and that up and down the busy street, and once or twice rushing aimlessly half-way up the inner stairs, and as often returning to the door. Apprehension was plain on his pale face, and he was clearly in a state that blinded his attention to the ordinary matters about him, just as happens when a man is in momentary and nervous expectation of some serious event. Noting these things as he passed, with no more than the observation that was his professional habit, Hewitt proceeded to his lunch. This done with, he returned to his office, perceiving, as he passed the next-door building, that the distracted Jew was no longer visible. It seemed plain that the person or the event he had awaited with such obvious nervousness had arrived and passed; one more of the problems, anxieties or crises that join and unravel moment by moment in the human ant-hill of London, had perhaps closed for good or ill within the past half-hour; perhaps it had only begun. A message awaited Hewitt at his office--an urgent message. The housekeeper had come in from next door, Kerrett reported, with an urgent request that Mr. Martin Hewitt would go immediately to the offices of Mr. Denson, on the third floor. The housekeeper seemed to know little or nothing of the business, except that a Mr. Samuel was alone in Mr. Denson's office, and had sent the message. With no delay Hewitt transferred himself to the next-door offices. There the housekeeper, who inhabited a uniform and a glass box opposite the foot of the first flight of stairs, directed Hewitt, with the remark that the gentleman was very impatient and very much upset. "Third floor, sir, second door on the right; name Denson on the door. There's no lift."