A dog reflects the family life. Whoever saw a frisky dog in a gloomy family, or a sad dog in a happy one? Snarling people have snarling dogs, dangerous people have dangerous ones.

Ex-Professor Moriarty of mathematical celebrity... is the Napoleon of crime, Watson.

I followed you.' I saw no one.' That is what you may expect to see when I follow you.

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.

There are always some lunatics about. It would be a dull world without them.

I think you want a little unofficial help. Three undetected murders in one year won't do, Lestrade. But you handled the Molesey Mystery with less than your usual - that's to say, you handled it fairly well.

Nothing clears up a case so much as stating it to another person.