The Count of Monte Cristo returns Madame de Villefort's call, and the whole house stirs because the man who saved Edward is now a guest as well as a debt. Edward is brought in out of curiosity, not gratitude. He plucks feathers from a parrot, calls Valentine melancholy, and says she is under the chestnut tree instead of with Noirtier. Later he tears pages from an album until his mother sends him away and the Count notes whether she closes the door behind him.
The Count pretends to remember meeting the family in Perugia at Corpus Christi, in the garden of the Hôtel des Postes. He describes the heat, the waiting horses, and a talk about poisons, especially aqua Tofana. Madame de Villefort grows uneasy but admits she recalls the conversation. Valentine enters looking pale, as if she has been crying, and is introduced with grave courtesy. When the clock strikes six, Madame de Villefort sends her to feed old Noirtier his dinner.
With Valentine gone, the Count keeps Madame de Villefort alone and turns the visit into a chemistry lesson. He speaks of Mithridates taking poison in small doses, of brucine and gradual doses that make a victim seem to die of natural illness, and of Eastern women who know how to kill without leaving a trace. He tells grim stories about the Abbé Adelmonte, who poisoned a cabbage, a rabbit, a hen, a vulture, and finally fish that could kill a dinner guest on the fifth remove.
Madame de Villefort listens with frightening interest. They discuss arsenic, conscience, Richard III, Lady Macbeth, and how a crime can be dressed as fate if the poisoner keeps calm and calls the act an elimination rather than murder. When she praises the drop that revived Edward, the Count explains how powerful his remedy is and gently mocks her own lozenges. He offers her his secret medicine, warning that one drop heals and several kill.
He refuses dinner because he has promised to escort a Greek princess to the opera. The next morning he sends the prescription she asked for. Madame de Villefort is left thinking he may be Adelmonte himself. The house that thanked him for saving a child has just received a manual for murder without trace.
Edward is the first poison in the room, and he is only a child. He boasts of pulling feathers from a parrot and of finding Valentine under the chestnut tree instead of beside Noirtier. The Count watches whether the mother shuts the door on him. Then the Perugia memory does its work. A man in a woollen mantle, a medical stranger at the Hôtel des Postes, a talk of aqua Tofana: Madame de Villefort admits the afternoon, and the Count admits he was the stranger.
What he teaches after Valentine is sent to feed her grandfather is a ladder, not a secret. Cabbage, rabbit, hen, vulture, fish, and a guest who dies on the fifth remove while doctors name a liver or a fever. Her eyes take fire at the Eastern women who can stupefy a doctor and amaze a confessor. When she asks for the drop that woke Edward, he gives her the shape of a cure that is also a weapon, and he smiles while he says prudence. The prescription arrives the next morning. She is left holding a manual and a suspicion that the man who saved her son may be Adelmonte under a Paris name.
