- Athelney Jones: It's quite simple, really. The two brothers have a quarrel over the inheritance. Then, one kills the other so as to claim the whole of it for himself, leaving the body here! Quite simple!
- Sherlock Holmes: And the dead man gets up to lock the door from the inside?
- Athelney Jones: ...There's a flaw there... Somewhere...
- Sherlock Holmes: Watson, how often have I said, "When you have eliminated the impossible, whatever remains, howeever improbable, must be the truth"?
- Sherlock Holmes: [Last lines] Love is an emotional thing. I shall never marry, lest I bias my judgment.
- Dr. Watson: I trust my judgement shall survive it. You are weary, Holmes. You don't ask much of life, do you?
- Sherlock Holmes: Work, my dear Watson, a problem to solve is all I ask. I cannot live without brainwork. Give me the pleasure of finding a field for my own peculiar powers. Give me work. This is my reward. And I am content.
- Sherlock Holmes: Don't tell me too much, Watson. Women are never to be trusted... even the best of them.
- Thaddeus & Bartholomew Sholto: As you can see, I am a refined man, and there is nothing more unaesthetic than a policeman.
- Thaddeus & Bartholomew Sholto: [as Watson, Holmes, and Miss Marston enter his room] Your servant, Miss Marston. Your servant. gentlemen. Pray, step into my sanctum, a small place of my own, an oasis of art in the howling desert of South London.