Continuity mistake: In the scene where Mary is eating her oatmeal while Martha is talking to her, take a look at Martha. While talking to Mary she spits out a piece of bread she was eating and this causes the little girl who plays Mary to momentarily slip out of character and smile (almost ready to laugh).
Colin Craven: You don't even care how I won't live to grow up.
Mary Lennox: Stop it. You'll live as long as I will. You just say that to make people feel sorry for you and do what you say.
Colin Craven: Don't you dare say that! Don't you dare say how I won't die.
Mary Lennox: Why, you're proud of it. It makes you feel important.
Mary Lennox: What's that?
Dickon: A fox cub. His name's Captain.
Mary Lennox: Dickon, are you still angry with me?
Dickon: When was I ever angry with thee?
Mary Lennox: Oh, good. Dickon, I've got so many secrets I'm just dying.
Dickon: Thou seems most healthy.
Mary Lennox: Dickon, I need you. All you have to do is listen. What good is a secret if there's no-one to tell it to?