The second most dangerous man in London.

“This is astonishing,” said I, as I handed back the volume. “The man’s career is that of an honourable soldier.”

“It is true,” Holmes answered. “Up to a certain point he did well. He was always a man of iron nerve, and the story is still told in India how he crawled down a drain after a wounded man-eating tiger. There are some trees, Watson, which grow to a certain height, and then suddenly develop some unsightly eccentricity. You will see it often in humans. I have a theory that the individual represents in his development the whole procession of his ancestors, and that such a sudden turn to good or evil stands for some strong influence which came into the line of his pedigree. The person becomes, as it were, the epitome of the history of his own family.”

“It is surely rather fanciful.”