He stood quite still for a moment, peering round as though listening. After a minute or two, seemingly satisfied, he switched on a torch he carried, and turned it rapidly round the room. Apparently he saw nothing unusual. The three watchers held their breath.

He went over to the same bit of panelled wall he had been examining the night before.

And then a terrible knowledge smote Bill. He was going to sneeze! The wild race through the dew-laden park the night before had given him a chill. All day he had sneezed intermittently. A sneeze was due now, and nothing on earth would stop it.

He adopted all the remedies he could think of. He pressed his upper lip, swallowed hard, threw back his head and looked at the ceiling. As a last resort he held his nose, and pinched it violently. It was of no avail. He sneezed.

A stifled, checked, emasculated sneeze, but a startling sound in the deadly quiet of the room.