It was long past Dr. Stuart's hours of consultation when I arrived at his house, and the servant showed me into a waiting-room, informing me that the doctor would join me in a few minutes. Directly she had gone out I took from the pocket of my tunic the sealed envelope which I had intended to lodge with the doctor. Pah! it was stained with blood which had trickled down from the wound in my scalp! Actually, you will say, there was no reason why I should place a letter in the hand of Dr. Stuart; my purpose would equally well be served by _pretending_ that I had done so. Ah, but I knew that I had to deal with clever people--with artists in crime--and it behooved me to be an artist also. I had good reason to know that their system of espionage was efficient; and the slipshod way is ever the wrong way. The unpleasantly sticky letter I returned to my pocket, looking around me for some means of making up any kind of packet which could do duty as a substitute. Beyond a curtain draped over a recess at one end of the waiting-room I saw a row of boxes, a box of lint and other medical paraphernalia. It was the doctor's dispensary. Perhaps I might find there an envelope. I crossed the room and looked. Immediately around the corner, on a level with my eyes, was a packet of foolscap envelopes and a stick of black sealing-wax! _Bien!_ all that I now required was a stout sheet of paper to enclose in one of those envelopes. But not a scrap of paper could I find, except the blood-stained letter in my pocket-- towards which I had formed a strong antipathy. I had not even a newspaper in my possession. I thought of folding three or four envelopes, but there were only six in all, and the absence of so many might be noted. Drawing aside a baize curtain which hung from the bottom shelf, I discovered a number of old card-board boxes. It was sufficient. With a pair of surgical scissors I cut a piece from the lid of one and thrust it into an envelope, gumming down the lapel. At a little gas jet intended for the purpose I closed both ends with wax and-- singular coincidence!--finding a Chinese coin fastened to a cork lying on the shelf, my sense of humour prompted me to use it as a seal! Finally, to add to the verisimilitude of the affair I borrowed a pen which rested in a bottle of red ink and wrote upon the envelope the number: 30, that day being the thirtieth day of the month. It was well that the artist within me had dictated this careful elaboration, as became evident a few minutes later when the doctor appeared at the head of a short flight of stairs and requested me to step up to his consulting-room. It was a small room, so that the window, over which a linen blind was drawn, occupied nearly the whole of one wall. As Dr. Stuart, having examined the cut on my scalp, descended to the dispensary for lint, the habits of a lifetime asserted themselves.