The doctor lived down criticism, lived down suspicion, and got together a remunerative practice. He had the largest flat in the building, one room of which was fitted up as a laboratory, for he had a passion for research. The mysterious murder of John Millinborn had given him a certain advertisement which had not been without its advantages. The fact that he had been in attendance on the millionaire had brought him a larger fame. His theories as to how the murder had been committed by some one who had got through the open window whilst the two men were out of the room had been generally accepted, for the police had found footmarks on the flowerbeds, over which the murderer must have passed. They had not, however, traced the seedy-looking personage whom Mr. Kitson had seen. This person had disappeared as mysteriously as he had arrived. Three months after the murder the doctor stood on the steps of the broad entrance-hall which led to the flats, watching the stream of pedestrians passing. It was six o'clock in the evening and the streets were alive with shop-girls and workers on their way home from business. He smoked a cigarette and his interest was, perhaps, more apparent than real. He had attended his last surgery case and the door of the "shop," with its sage-green windows, had been locked for the night. His eyes wandered idly to the Oxford Street end of the thoroughfare, and suddenly he started. A girl was walking toward him. At this hour there was very little wheeled traffic, for Lattice Street is almost a cul-de-sac, and she had taken the middle of the road. She was dressed with that effective neatness which brings the wealthy and the work-girl to a baffling level, in a blue serge costume of severe cut; a plain white linen coat-collar and a small hat, which covered, but did not hide, a mass of hair which, against the slanting sunlight at her back, lent the illusion of a golden nimbus about her head. The eyes were deep-set and wise with the wisdom which is found alike in those who have suffered and those who have watched suffering. The nose was straight, the lips scarlet and full. You might catalogue every feature of Oliva Cresswell and yet arrive at no satisfactory explanation for her charm. Not in the clear ivory pallor of complexion did her charm lie. Nor in the trim figure with its promising lines, nor in the poise of head nor pride of carriage, nor in the ready laughter that came to those quiet eyes. In no one particular quality of attraction did she excel. Rather was her charm the charm of the perfect agglomeration of all those characteristics which men find alluring and challenging. She raised her hand with a free unaffected gesture, and greeted the doctor with a flashing smile. "Well, Miss Cresswell, I haven't seen you for quite a long time." "Two days," she said solemnly, "but I suppose doctors who know all the secrets of nature have some very special drug to sustain them in trials like that."