"Nothing at all, of course," replied Poirot, smiling. "But we were speaking of the arrest of Dr. Bauerstein."

"Well, he is arrested for the murder of Mrs. Inglethorp----"

"What?" cried Poirot, in apparently lively astonishment. "Dr. Bauerstein arrested for the murder of Mrs. Inglethorp?"

"Yes."

"Impossible! That would be too good a farce! Who told you that, my friend?"

"Well, no one exactly told me," I confessed. "But he is arrested."

"Oh, yes, very likely. But for espionage, mon ami."

"Espionage?" I gasped.

"Precisely."

"Not for poisoning Mrs. Inglethorp?"

"Not unless our friend Japp has taken leave of his senses," replied Poirot placidly.

"But--but I thought you thought so too?"

Poirot gave me one look, which conveyed a wondering pity, and his full sense of the utter absurdity of such an idea.

"Do you mean to say," I asked, slowly adapting myself to the new idea, "that Dr. Bauerstein is a spy?"

Poirot nodded.

"Have you never suspected it?"

"It never entered my head."