The mysterious Hernando went on his way, by the southern sweep of Trafalgar Square and Cockspur Street, to the Haymarket, and Lefevre followed with attention and curiosity bent on him, but yet with so little thought of playing spy that, if Hernando had gone any other way or had returned along the Strand, he would probably have let him go. And as they went on, the doctor could not but note, as before, how the object of his curiosity lingered wherever there was a press of people, whether on the pavement or on a refuge at a crossing, and hurried on wherever the pavement was sparsely peopled or whenever the persons encountered were at all advanced in years. Indeed, the farther he followed the more was his attention compelled to remark that Hernando sharply avoided contact with the weakly, the old, and the decrepit, and wonder why the young people of either sex whom he brushed against should turn as if the touch of him waked suspicion and a something hostile. Thus they traversed the Haymarket, the Criterion pavement, and, flitting across to the Quadrant, the more popular side of Regent Street, among pushing groups, weary stragglers, and steady pedestrians. Lefevre had a mind to turn aside and go home when he was opposite Vigo Street, but he was drawn on by the hope of observing something that might give him a clue to the Courtney mystery. When Oxford Circus was reached, however, Hernando jumped into a cab and drove rapidly off, and Lefevre returned to his own fireside. He sat for some time over a cigar and a grog, walking in imagination round and round the mystery, which steadfastly refused to dissolve or to be set aside. His own honour, and perhaps the peace of his mother and sister, were involved in it. He was resolved to ask Julius for an explanation as soon as he could come to speech with him; but yet, in spite of that assurance which he gave himself, he returned to the mystery again and again, and beset and bewildered himself with questions: Why was Julius estranged from his father? What was the secret of the old man's life which had left such an awful impress on his face? And why was he nightly haunting the busiest pavements of London, in the crowd, but not of it, urged on as by some desire or agony?