For his pivotal scene, Ronald Reagan researched extensively, meeting with amputees and doctors to find out how they reacted in similar situations. He deliberately had little sleep the night before the scene was shot. Sam Wood didn't let him rehearse the scene either, so he could tackle it fresh. The scene was captured in one take.
When Parris is speaking to his instructor in Vienna, Dr. Kendell strikes a match to light his pipe. In the next shot, the match has disappeared and there is no evidence that he lit the pipe.
Col. Skeffington: [Referring to the dying Madame von Eln]
When she passes, how much passes with her! - a whole way of life, a way of gentleness and honor and dignity. These things are going, Henry, and they may never come back to this world.
Drake McHugh, as a boy: [to Parris, as Dr. Gordon operates on a friend's father]
Let's get out of here! I never heard a grown man scream and holler like this before, did you?