Violence is sometimes a duty.

I rose to go, but Holmes caught me by my wrist and pushed me back into my chair. 'It is both, or none,' said he. 'You may say before this gentleman anything which you may say to me.

The world is full of obvious things which nobody by any chance ever observes.

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.

In the year 1878 I took my degree of Doctor of Medicine of the University of London, and proceeded to Netley to go through the course prescribed for surgeons in the army. Having completed my studies there, I was duly attached to the Fifth Northumberland Fusiliers as Assistant Surgeon.

If my future were black, it was better surely to face it like a man than to attempt to brighten it by mere will-o’-the-wisps of the imagination.

Let me run over the principal steps. We approached the case, you remember, with an absolutely blank mind, which is always an advantage. We had formed no theories. We were simply there to observe and to draw inferences from our observations.