Circumstantial evidence is occasionally very convincing, as when you find a trout in the milk, to quote Thoreau's example.

I think that I had better go, Holmes." "Not a bit, doctor. Stay where you are. I am lost without my Boswell.

Detection is, or ought to be, an exact science and should be treated in the same cold and unemotional manner. You have attempted to tinge it with romanticism, which produces much the same effect as if you worked a love-story ... Some facts should be suppressed, or, at least, a just sense of proportion should be observed in treating them. The only point in the case which deserved mention was the curious analytical reasoning from effects to causes, by which I succeeded in unravelling it.'' —Sherlock Holmes on John Watson's "pamphlet", "A Study in Scarlet".

Beyond the obvious facts that he has at some time done manual labour, that he takes snuff, that he is a Freemason, that he has been in China, and that he has done a considerable amount of writing lately, I can deduce nothing else.

I should dearly love that the world should be ever so little better for my presence. Even on this small stage we have our two sides, and something might be done by throwing all one's weight on the scale of breadth, tolerance, charity, temperance, peace, and kindliness to man and beast. We can't all strike very big blows, and even the little ones count for something.

All other men are specialists, but his specialism is omniscience.

No violence, gentlemen — no violence, I beg of you! Consider the furniture!