The mystery had now reached its climax. First, the man had been undoubtedly murdered. Secondly, it was absolutely certain that no conceivable person had done it. It was therefore time to call in the great detective. He gave one searching glance at the corpse. In a moment he whipped out a microscope. "Ha ha " he said, as he picked a hair off the lapel of the dead man's coat. "The mystery is now solved." He held up the hair. "Listen," he said, "we have...