I pricked up my ears. For the last three days the papers had been full of the strange disappearance of Mr. Davenheim, senior partner of Davenheim and Salmon, the well-known bankers and financiers. On Saturday last he had walked out of his house, and had never been seen since. I looked forward to extracting some interesting details from Japp.

“I should have thought,” I remarked, “that it would be almost impossible for anyone to ‘disappear’ nowadays.”

Poirot moved a plate of bread and butter the eighth of an inch, and said sharply:

“Be exact, my friend. What do you mean by ‘disappear’? To which class of disappearance are you referring?”

“Are disappearances classified and labelled, then?” I laughed.

Japp smiled also. Poirot frowned at us both.