"O'Brien comes from Dublin, you see," put in Marsden, "so you must make allowances for a touch of bitterness." He pulled forward a chair, and, thrusting his hand into his pocket, produced a large rubber pouch. "Make yourself comfortable and try a pipe of this tobacco, doctor," he added. "It was given to me by a ship's captain, and they don't generally go far wrong--not from what I've seen of them." Colin took the proffered seat, and, drawing out his briar, proceeded to fill it carefully with the fragrant brown flakes. "I'm rather interested in 'Ginger Dick,'" he remarked. "One would hardly take him for a Napoleon of crime, judging by his appearance." "No, his looks aren't anything to shout about," agreed Marsden. "All the same, he's a dangerous little devil if ever there was one. As I told you the other day, he's in with all the lowest scum of the Turf, and, thanks to him and his crowd, there are several of our boys on the retired list, and likely to remain there." "It never occurred to me before," said Colin, "but I suppose there are healthier occupations than being a detective on a racecourse." "You can back on that," was O'Brien's rejoinder. "I've had some of it myself, and, though I'm partial to what you may call an active life, I wasn't exactly sorry when they shifted me to another department." "Tell him some of your experiences, Pat," suggested Inspector Marsden. "It's no use having a distinguished guest if you don't try to entertain him." The Irishman, who apparently only needed this encouragement, plunged at once into a series of reminiscences, all dealing with that dark underworld of ruffianism which lurks furtively beneath the brilliant surface of racing. He told his stories well, and Colin, who knew little or nothing about the Turf, listened to him with absorbed interest. It was not, indeed, until the hands of the office clock were pointing to the half-hour that he reluctantly knocked out his pipe into the fireplace and rose from his chair. "I hate to break up this cheerful party," he said truthfully, "but I've promised to be down in Shadwell by four, and I've got an unpleasant sort of feeling that I must be keeping you both from your work." "Oh, you needn't worry about that," replied Marsden, smiling. "I'm fixed here until midnight anyway, and, no matter how busy Pat is, he can always find time to talk." "I want to hear some more of his reminiscences," said Colin, "and yours, too. Perhaps if you could both get away together the same evening you would come out and feed with me? We could go to the Cheshire Cheese or somewhere like that. I can't ask you to my place, because at present I'm acting as bottle-washer to Professor Carter." "The Cheshire Cheese sounds all right to me," said O'Brien approvingly. "You give us a ring when you've got a spare night, and we'll try and fix it up."