I was watching him closely as I gave the message, and I fancied that I saw a momentary flicker of discomposure. If so, it passed almost immediately.

“She is absolutely positive they are not brown?”

“Absolutely.”

“Ah!” said Poirot regretfully. “That is a pity.”

And he seemed quite crestfallen.

He entered into no explanations, but at once started a new subject of conversation.

“The housekeeper, Miss Russell, who came to consult you on that Friday morning⁠—is it indiscreet to ask what passed at the interview⁠—apart from the medical details, I mean?”

“Not at all,” I said. “When the professional part of the conversation was over, we talked for a few minutes about poisons, and the ease or difficulty of detecting them, and about drug-taking and drug-takers.”