"I owe something both to you and to this young lady," he continued. "If you hadn't come along just when you did I'd probably have got my head kicked in." "You needn't thank me," protested Colin. "There's nothing I enjoy better than a good scrap." He glanced round the late field of battle with a certain amount of amused curiosity. Three fresh and energetic-looking policemen had already appeared. One of them was grasping the arm of the now handcuffed prisoner, a second knelt beside the body of his injured comrade, while the third, with that scant ceremony which distinguishes the Metropolitan force, was thrusting back a rapidly increasing throng of interested spectators. "What's it all about?" asked Colin. Rummaging in his waistcoat pocket, the big man produced a dilapidated card. "You'll see my name there," he said. "Inspector Marsden of the C.I.D." He jerked his head in the direction of the captive--a short, sandy-haired individual with a face like a rather disagreeable ferret. "You've helped us to get hold of a gentleman we've been wanting badly at the Yard for the last two months. That's 'Ginger Dick,' the leader of the toughest race-course gang in England." "He must be fairly popular with his friends," observed Colin. "At least, they seemed quite anxious not to lose his society." The Inspector smiled grimly. "You don't know 'em, sir. You can take it from me that all they're worrying about is whether he's going to split on 'em. There isn't a man in that crowd who wouldn't sell his own mother." He moved over to the second constable, who was still busy with his unconscious mate. "What's the damage?" he asked. "Anything serious?" Colin stepped across after him. "You'd better let me have a look," he said. "I'm a doctor." The two men at once made way, and, kneeling down in the gutter, he rapidly examined his patient's condition. "You must get him to hospital as quick as you can," he said, looking up at the Inspector. "He's had a pretty bad crack on the head, and the sooner he's under treatment the better." He rose to his feet and brushed off the dust from his trousers. "Take him along to St. Christopher's," he added. "Tell them that Doctor Gray sent you, and that it's a case which requires immediate attention." The Inspector nodded, and, having despatched one of his assistants to fetch an ambulance, turned back and addressed himself to the girl. "You'll pardon me for not having thanked you before, miss," he said. "I never saw anything pluckier in my life than the way you chipped in and blew that whistle. There's not one young lady in a thousand who'd have had the nerve to do it." The recipient of his praises coloured delicately. "If you don't mind," he continued, "I'll make a note of your name and address. We might be glad of your evidence, and I know the commissioner would like to write you a little letter to send you his official thanks."