“Now, Watson, now!” cried Holmes with frenzied eagerness. All the demoniacal force of the man masked behind that listless manner burst out in a paroxysm of energy. He tore the drugget from the floor, and in an instant was down on his hands and knees clawing at each of the squares of wood beneath it. One turned sideways as he dug his nails into the edge of it. It hinged back like the lid of a box. A small black cavity opened beneath it. Holmes plunged his eager hand into it and drew it out with a bitter snarl of anger and disappointment. It was empty.

“Quick, Watson, quick! Get it back again!” The wooden lid was replaced, and the drugget had only just been drawn straight when Lestrade’s voice was heard in the passage. He found Holmes leaning languidly against the mantelpiece, resigned and patient, endeavouring to conceal his irrepressible yawns.