I think there are certain crimes which the law cannot touch, and which therefore, to some extent, justify private revenge.

My uncle, Mr. Stephen Maple, had been at the same time the most successful and the least respectable of our family, so that we hardly knew whether to take credit for his wealth or to feel ashamed of his position.

He [Professor Moriarty] is the Napoleon of crime, Watson. He is the organizer of half that is evil and of nearly all that is undetected in this great city. He is a genius, a philosopher, an abstract thinker. He has a brain of the first order.

I have heard, Mr. Holmes, that you can see deeply into the manifold wickedness of the human heart.

Living, as I do, in an educated and scientific atmosphere, I could not have conceived that the first principles of zoology were so little known. Is it possible that you do not know the elementary fact in comparative anatomy, that the wing of a bird is really the forearm, while the wing of a bat consists of three elongated fingers with membranes between?

A man always finds it hard to realize that he may have finally lost a woman's love, however badly he may have treated her.

It’s every man’s business to see justice done.