I pondered the matter.

“It seems a little unfair on Mary Marvell. She has lost her diamond through no fault of her own.”

“Bah!” said Poirot brutally. “She has a magnificent advertisement. That is all she cares for, that one! Now the other, she is different. Bonne mère, très femme! ”

“Yes,” I said doubtfully, hardly sharing Poirot’s views on femininity. “I suppose it was Rolf who sent her the duplicate letters.”