Thus musing, he walked on, taking, without noting it, the most frequented turnings, and soon he found himself in the Strand. It was that middle time of evening, after the theatres and restaurants have sucked in their crowds, when the frequenters of the streets have some reserve in their vivacity, before reckless roisterers have begun to taste the lees of pleasure, and to shout and jostle on the pavements. He was walking on the side of the way next the river, when, near the Adelphi, he became aware of a man before him, wearing a slouch-hat and a greatcoat--a man who appeared to choose the densest part of the throng, to prefer to be rubbed against and hustled rather than not. There was something about the man which held Lefevre's attention and roused his curiosity--something in the swing of his gait and the set of his shoulders. The man, too, seemed urged on by a singular haste, which permitted him to be the slowest and easiest of passengers in the thick of the crowd, but carried him swiftly over the less frequented parts of the pavement. The doctor began to wonder if he was a pickpocket, and to look about for the watchful eye of a policeman. He kept close behind him past the door of the Strand Theatre, when the throng became slacker, and the man turned quickly about and returned the way he had come. Then Lefevre had a glimpse of his face,--the merest passing glimpse, but it made him pause and ask himself where he had seen it before. A dark, foreign-looking man, with a haggard appeal in his eye: he tried to find the place of such a figure in his memory, but for the time he tried in vain. Before the doctor recovered himself the man was well past, and disappearing in the throng. He hurried after, determined to overtake him, and to make a full and satisfying perusal of his face and figure. He found that difficult, however, because of the man's singular style of progression. To maintain an even pace for himself, moreover, Lefevre had to walk very much in the roadway, the dangers of which, from passing cabs and omnibuses, forbade his fixing his attention on the man alone. Yet he was more and more piqued to look him in the face; for the longer he followed him the more he was struck with the oddity of his conduct. He had already noted how he hurried over the empty spaces of pavement and lingered sinuously in the thronged parts; he now remarked further that those who came into immediate contact with him (and they were mostly young people who were to be met with at that season of the night) glanced sharply at him, as if they had experienced some suspicious sensation, and seemed inclined to remonstrate, till they looked in his face.