One thought that flew across my mind was that Doctor Roycroft was very intimate with the Ryleys, and had doubtless somehow informed them of my aunt's death. This explained Fred Ryley's strange words and attitude to me on the way from the station. The young man had been too timid to stop me. The matter was a trifle, but another idea that struck me was not a trifle, though I strove to make it so. My aunt had died about midnight, and it was at midnight that Diaz and I had heard the mysterious knock on his sitting-room door. At the time I had remarked how it resembled my aunt's knock. Occasionally, when the servants overslept themselves, Aunt Constance would go to their rooms in her pale-blue dressing-gown and knock on their door exactly like that. Could it be that this was one of those psychical manifestations of which I had read? Had my aunt, in passing from this existence to the next, paused a moment to warn me of my terrible danger? My intellect replied that a disembodied soul could not knock, and that the phenomenon had been due simply to some guest or servant of the hotel who had mistaken the room, and discovered his error in time. Nevertheless, the instinctive part of me--that part of us which refuses to fraternize with reason, and which we call the superstitious because we cannot explain it--would not let go the spiritualistic theory, and during all my life has never quite surrendered it to the attacks of my brain. There was a long pause. 'No,' I said; 'I will go upstairs alone;' and I went, leaving my cloak and hat with Rebecca.