The Mysterious Affair at Styles: Chapter 9: Dr. Bauerstein Summary & Analysis

Hastings walks outside and sees Lawrence playing croquet, so he approaches him and delivers Poirot’s message. He explains that Poirot wanted him to wait until they were alone before saying, “Find the extra coffee cup, and you can rest in peace.” Lawrence has no idea what he’s talking about. He asks him to say it again, but hearing it a second time doesn’t help him make any sense of the words. 

That afternoon, Hastings goes for a walk through the woods. He lies underneath a tree at a certain point and drifts to sleep. When he awakes, he realizes that John and Mary Cavendish are having an argument in the woods. They don’t know he’s nearby, and though he doesn’t necessarily want to, he can’t help but listen to their conversation. John asks Mary if she’s going to keep seeing Dr. Bauerstein even though John himself doesn’t want her to. Mary says she will do whatever she wants, adding that John shouldn’t act like he doesn’t have his own secret acquaintances. Just before she leaves, he catches her arm and asks if she’s in love with Bauerstein. “Perhaps,” she says before walking away.

Once Mary is gone, Hastings emerges as if he’s just walking through the woods. John doesn’t seem to suspect that he overheard anything, merely greeting him and starting to complain about the publicity that the murder has attracted to the family. He also expresses distress about the murderer’s identity—if it’s not Alfred Inglethorp, he says, then it must be somebody else in the house. As soon as he says this, Hastings has an idea, which he blurts out: the murderer must be Dr. Bauerstein. He even tells John that Poirot suspects Bauerstein, citing Poirot’s excitement after hearing that Bauerstein visited the house on Tuesday evening. Hastings himself thinks Bauerstein must have poisoned the coffee when Alfred let him into the house.

John Cavendish—whom Hastings has previously suggested is somewhat slow and unimaginative—is hesitant to go along with Hastings’s theory. He points out that Bauerstein wouldn’t have known whose cup he was poisoning. Hastings takes a moment and then suggests that the coffee wasn’t what killed Mrs. Inglethorp. Instead, Bauerstein must have poisoned her cocoa, which is why Poirot took it to be analyzed. But John points out that Bauerstein himself had already had the cocoa analyzed—a point Hastings latches onto, insisting that Bauerstein probably substituted the sample for one without poison. But then John reminds Hastings that cocoa isn’t bitter enough to mask the taste of strychnine. 

Hastings is no longer sure of his theory. But then he realizes that Dr. Bauerstein might have had an accomplice—someone, perhaps, like Mary Cavendish. He hopes John hasn’t just thought the same thing. He also suddenly remembers the conversation he overheard between Mary and Mrs. Inglethorp, thinking that maybe Mrs. Inglethorp found out about her feelings for Bauerstein and threatened to tell John, ultimately giving Mary a motive to kill her. What’s more, he realizes that Miss Howard’s reluctance to admit her true suspicions supports the idea of Mary being the murderer. Evelyn Howard, after all, wouldn’t want to accuse Mary, and even Mrs. Inglethorp herself probably wouldn’t want to see the Cavendish name fall into disgrace, even if that meant letting her own death go “unavenged.”

Not wanting John to think too much about the matter anymore, Hastings changes the subject. They return to Styles Court, where everyone is gathering for tea. Cynthia says she wants to talk to Hastings afterwards, so they go for a walk. She tells him that Mrs. Inglethorp promised to leave her money—but she didn’t do it, and now Cynthia doesn’t know what she should do. She wants to know if Hastings thinks she should leave Styles Court, and when he insists that everyone would be sad to see her go, she says that Mary Cavendish hates her. She also thinks Lawrence hates her.

As she complains about everyone at Styles Court hating her, Cynthia throws herself on the grass. Hastings realizes she’s quite attractive and suddenly finds himself asking her to marry him. She can’t believe her ears, and instead of giving him a straight answer, she starts laughing hysterically. He’s offended, but she tries to assure him that he shouldn’t be—he clearly doesn’t mean what he says. She jokes that he should be careful about proposing to people out of nowhere; somebody might actually say yes sometime! She then thanks him for cheering her up and walks back.

Dissatisfied with his interaction with Cynthia, Hastings decides to go into town to check on Bauerstein, thinking that somebody should be keeping tabs on him. When he goes to Bauerstein’s apartment, though, a woman downstairs tells him that the police took him away. Before asking any other questions, Hastings sprints off to find Poirot.