"Oh, really?" he said, calmly. "And why?"
"Why? Because the incident has occurred before, seventy or eighty years ago. Edgar Allan Poe made it the subject of one of his finest tales. In those circumstances, the key to the riddle was easy enough to find."
Arsène Lupin took my arm, and walking away with me, said:
"When did you guess it, yourself?"
"On reading your letter," I confessed.
"And at what part of my letter?"
"At the end."
"At the end, eh? After I had dotted all the i's. So here is a crime which accident causes to be repeated, under quite different conditions, it is true, but still with the same sort of hero; and your eyes had to be opened, as well as other people's. It needed the assistance of my letter, the letter in which I amused myself—apart from the exigencies of the facts—by employing the argument and sometimes the identical words used by the American poet in a story which everybody has read. So you see that my letter was not absolutely useless and that one may safely venture to repeat to people things which they have learnt only to forget them."
Wherewith Lupin turned on his heel and burst out laughing in the face of an old monkey, who sat with the air of a philosopher, gravely meditating.