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The Mystery of the Yellow Room · Chapter

An Act of Mademoiselle Stangerson explained

Rouletabille reveals his secret preparations to catch the murderer, positioning Sainclair as a hidden observer in a triangular closet near Arthur Rance's room.

What happens

Rouletabille reveals his secret preparations to catch the murderer, positioning Sainclair as a hidden observer in a triangular closet near Arthur Rance's room. During dinner, they witness Mademoiselle Stangerson secretly pour the contents of a phial into her father's glass. Arthur Rance, an old American friend of the Stangersons, joins them at the Donjon Inn and expresses his own theories about the crime, hinting at suspicion toward Robert Darzac. Rouletabille remains indifferent to Rance's presence and spends the afternoon exploring the grotto of Sainte-Geneviève, avoiding discussion of the case until nightfall.

Themes in this chapter

  • Secrecy and Silence

    Rouletabille keeps his preparations secret from Sainclair until nightfall, and Mademoiselle Stangerson secretly administers a substance to her father's drink.

  • The Outsider as Detective

    Rouletabille, a young reporter, orchestrates a trap and positions his friend as a hidden observer, acting outside official police methods.

Characters to notice

  • Joseph Rouletabille

    Reveals his trap for the murderer, positions Sainclair in a hidden closet, and shows indifference to Arthur Rance's presence.

  • Sainclair

    Reluctantly agrees to spy from the triangular closet, feeling like a common policeman but driven by curiosity and a desire to help.

  • Mr. Arthur W. Rance

    An old American friend of the Stangersons, a phrenologist and inebriate, who suspects Robert Darzac of the crime and speaks with irony about Rouletabille's investigation.

  • Mademoiselle Stangerson

    Secretly pours the contents of a phial into her father's glass during dinner, observed by Rouletabille and Sainclair.

  • Professor Stangerson

    Dines with his daughter in the drawing-room; unknowingly receives a doctored drink from her.

  • Frédéric Larsan

    Mentioned as having provided background information about Arthur Rance's history with the Stangersons.

Key passages

  • I expressed some doubt on this, reminding him of his disappearance in the gallery, and suggested that the same phenomenon might occur again. He answered that he hoped it would. He desired nothing more.

    Sainclair questioned Rouletabille's confidence, recalling his earlier vanishing act in the gallery, but Rouletabille said he actually wanted that to happen again.

    Rouletabille's cryptic confidence suggests he expects the murderer to repeat his strange escape.

  • As the door remained open, we distinctly saw Mademoiselle Stangerson, taking advantage of the steward's absence, and while her father was stooping to pick up something he had let fall, pour the contents of a phial into Monsieur Stangerson's glass.

    With the door ajar, Rouletabille and Sainclair watched Mademoiselle Stangerson secretly empty a small bottle into her father's drink while he was distracted.

    This act raises questions about Mademoiselle Stangerson's motives and her possible role in the mystery.