N2: Watson and Holmes are taking Helen to her aunt’s house.
Helen: Mr. Holmes, I must know. How did you solve it?
Holmes: With the doors and windows locked, the danger had to come from Roylott’s room.
Watson: How did you know Roylott had a snake?
Holmes: He kept wild animals. A snake was a logical guess. And its poison is hard to trace.
Helen: But how did he do it?
Holmes: The seat of his chair looked like someone had been standing on it. That’s how he pushed the snake through the hole.
Helen: Then it slithered down the bell rope to the bed.
Holmes: When Roylott whistled, the snake returned.
Watson: Ah, he used the milk to train it!
Holmes: Yes. The clanging sound was the doctor shutting the snake in the safe.
Watson: How did he know the snake would kill?
Holmes: He sent the snake in night after night until it found its victim.
Helen: But you were waiting this time.
Holmes: Indeed. I hit it with my cane, making it angry.
Watson: Then it went back through the hole . . .
Holmes: And bit the first person it saw: Roylott.
Helen: So many little clues, Mr. Holmes! You added them up and saved my life.
Holmes: My dear, to a great mind, nothing is little!