Sherlock Holmes: [a portrait that he has just seen fascinates him] You must - you must dine with us before you sail.
Sir Henry Baskerville: Well, there's the old boy himself - Sir Hugo, the Beast of the Baskervilles.
Dr. Watson: Done by Ransome, one of the minor painters.
Sir Henry Baskerville: I don't imagine it's very valuable.
Sherlock Holmes: I can't quite agree with you, Sir Henry.
[ominously]
Sherlock Holmes: One day, it might prove to be of the greatest value.

Sherlock Holmes: Do you remember that missing boot, Watson? Why do you suppose the brown one, the one that had never been worn, was so mysteriously replaced and the black one taken?
Dr. Watson: Why?
Sherlock Holmes: Because the brown one would never have had the scent of the owner - and the black one had!

Sherlock Holmes: The only way to nab our man is to catch him in the act - catch him so that there's no escape, no alibi. And that means gambling with Sir Henry's life.
Dr. Watson: [horrified] But...
Sherlock Holmes: Gambling to save his life. But we've got to take that chance.

Sherlock Holmes: There are still some gaps to be filled, but all in all, things are becoming a little clearer.
Dr. Watson: Not to me, I assure you; it's all a hopeless jumble. Stapleton, Franklin, the Barrymans - put it all together and what have you got?
Sherlock Holmes: Murder, my dear Watson. Refined, cold-blooded murder.
Dr. Watson: Murder?
Sherlock Holmes: There's no doubt of it in my mind. Or perhaps I should say, my imagination. For that's where crimes are conceived and they're solved - in the imagination.

Dr. Watson: It's a pity you didn't think about bringing that infernal violin of yours - to regale me with some of your music!
Sherlock Holmes: I DID, my dear Watson! Anything to oblige!
[he whips out the violin and begins to play]

Dr. Watson: Then, why are we rushing up to London, leaving Sir Henry entirely alone and unprotected?
Sherlock Holmes: We're not, my dear Watson. We're just giving the impression of rushing up to London.

James Mortimer, M.D.: Mr. Holmes, we've admired you in the past as does every Englishman. Your record as our greatest detective is known throughout the world. But this - seeing how you work - knowing that there is in England such a man as you gives us all a sense of safety and security. God bless you, Mr. Holmes!

James Mortimer, M.D.: Mr. Holmes, you're the one man in all England who can help me... I am in mortal fear that Sir Henry's life will be snuffed out.

[last lines]
Sherlock Holmes: Oh, Watson - the needle!