In glancing over the somewhat incoherent series of memoirs with which I have endeavoured to illustrate a few of the mental peculiarities of my friend, Mr. Sherlock Holmes, I have been struck by the difficulty which I have experienced in picking out examples which shall in every way answer my purpose. For in those cases in which Holmes has performed some tour-de-force of analytical reasoning, and has demonstrated the value of his peculiar methods of investigation, the facts themselves have often been so slight or so commonplace that I could not feel justified in laying them before the public. On the other hand, it has frequently happened that he has been concerned in some research where the facts have been of the most remarkable and dramatic character, but where the share which he has himself taken in determining their causes has been less pronounced than I, as his biographer, could wish. The small matter which I have chronicled under the heading of “A Study in Scarlet,” and that other later one connected with the loss of the Gloria Scott, may serve as examples of this Scylla and Charybdis which are forever threatening his historian. It may be that, in the business of which I am now about to write, the part which my friend played is not sufficiently accentuated; and yet the whole train of circumstances is so remarkable that I cannot bring myself to omit it entirely from this series.

It had been a close, rainy day in October. Our blinds were halfdrawn, and Holmes lay curled upon the sofa, reading and re-reading a letter which he had received by the morning post. For myself, my term of service in India had trained me to stand heat better than cold, and a thermometer of 90 was no hardship. But the paper was uninteresting. Parliament had risen. Everybody was out of town, and I yearned for the glades of the New Forest or the shingle of Southsea. A depleted bank account had caused me to postpone my holiday, and as to my companion, neither the country nor the sea presented the slightest attraction to him. He loved to lie in the very centre of five millions of people, with his filaments stretching out and running through them, responsive to every little rumour or suspicion of unsolved crime.