surgical appliance—at least it was not like any surgical instrument that was known to me.
I turned it over and over and cudgeled my brains; and then I had a brilliant idea. Was it a reed pen of which the point had been broken off? I knew that reed pens were still in use by draughtsmen of decorative leanings with an affection for the "fat line." Could any of our friends be draughtsmen? This seemed the most probable solution of the difficulty, and the more I thought about it the more likely it seemed. Draughtsmen usually sign their work intelligibly, and even when they use a device instead of a signature their identity is easily traceable. Could it be that Mr. Graves, for instance, was an illustrator, and that Thorndyke had established his identity by looking through the works of all the well-known thick-line draughtsmen?
This problem occupied me for the rest of the day. My explanation did not seem quite to fit Thorndyke's description of his methods; but I could think of no other. I turned it over during my solitary lunch; I meditated on it with the aid of several pipes in the afternoon; and having refreshed my brain with a cup of tea, I went forth to walk in the Temple gardens—which I was permitted to do without breaking my parole—to think it out afresh.
The result was disappointing. I was basing my reasoning on the assumption that the pieces of reed were parts of a particular appliance, appertaining to a particular craft; whereas they
