"Good. One, two, three, four, five--but where, then, is the cup
of Mr. Inglethorp?"

"He does not take coffee."

"Then all are accounted for. One moment, my friend."

With infinite care, he took a drop or two from the grounds in
each cup, sealing them up in separate test tubes, tasting each in
turn as he did so. His physiognomy underwent a curious change.
An expression gathered there that I can only describe as half
puzzled, and half relieved.

"Bien!" he said at last. "It is evident! I had an idea--but
clearly I was mistaken. Yes, altogether I was mistaken. Yet it
is strange. But no matter!"

And, with a characteristic shrug, he dismissed whatever it was
that was worrying him from his mind. I could have told him from
the beginning that this obsession of his over the coffee was
bound to end in a blind alley, but I restrained my tongue. After
all, though he was old, Poirot had been a great man in his day.

"Breakfast is ready," said John Cavendish, coming in from the
hall. "You will breakfast with us, Monsieur Poirot?"

Poirot acquiesced. I observed John. Already he was almost
restored to his normal self. The shock of the events of the last
night had upset him temporarily, but his equable poise soon swung