'I had had a sharp run,' Mr. Cupples reminded him. 'Well, approaching the hotel from the back I could see into the writing-room through the open window. There was nobody in there, so I climbed over the sill, walked to the bell and rang it, and then sat down to write a letter I had meant to write the next day. I saw by the clock that it was a little past eleven. When the waiter answered the bell I asked for a glass of milk and a postage stamp. Soon afterwards I went up to bed. But I could not sleep.'
Mr. Cupples, having nothing more to say, ceased speaking. He looked in mild surprise at Trent, who now sat silent, supporting his bent head in his hands.
'He could not sleep,' murmured Trent at last in a hollow tone. 'A frequent result of over-exertion during the day. Nothing to be alarmed about.' He was silent again, then looked up with a pale face. 'Cupples, I am cured. I will never touch a crime-mystery again. The Manderson affair shall be Philip Trent's last case. His high-blown pride at length breaks under him.' Trent's smile suddenly returned. 'I could have borne every-
