Cautiously he pressed it. Nothing seemed to happen. But when he grasped the bedpost so that he could swing his feet back down to the floor, the top came away in his hand. Beneath it was an empty cavity with a flat, unvarnished wooden base, in the centre of which, so small as to be barely noticeable, was a tiny wooden knob. He grasped it between thumb and forefinger, pulled, and slowly withdrew a plain wooden case. There was a wonderful exactness to how it fitted.
