I had only just let myself into the hall of the quiet house in the respectable street beside the British Museum when my ear was startled by the subdued shrilling of the telephone bell overhead. Whether this was the first time it had sounded, or whether that alarming call was being repeated for the second or third time, I had no means of knowing, as I turned hurriedly to fasten the front door behind me. Cautiously, and yet as swiftly as I dared, I shot the bolts and began speeding on tiptoe up the two flights of stairs between me and safety from detection. The night telephone was placed beside my bed on the second floor, but Sir Frank Tarleton slept on the same landing; and unless I could reach my room and still that persistent ringing before it penetrated through his slumber I ran the risk of meeting him coming out to find why it was not answered. And not for much, not for very much, would I have had the great consultant see me returning to his house at an hour when daylight was already flooding the deserted streets of the still sleeping city. There was something ominous in the continuous peal that sounded louder and louder in my ears with every step I made towards it. It seemed as though the unknown caller must know of my predicament and be bent on exposing me. I clutched the rail of the banisters to steady myself as I panted up those interminable stairs in the darkness, and my feet felt clogged like those of one in a nightmare as I lifted them from step to step; all the while racking my brains for some excuse to offer for the breach of duty I had been guilty of in spending the night elsewhere. For my real excuse, the only one that could