THE great detective sat in his office. He wore a long green gown and half a dozen secret badges pinned to the outside of it. Three or four pairs of false whiskers hung on a whisker-stand beside him. Goggles, blue spectacles and motor glasses lay within easy reach. He could completely disguise himself at a second's notice. Half a bucket of cocaine and a dipper stood on a chair at his elbow. His face was absolutely impenetrable.