Jones

X. Jones is the story where midget-hating tycoon Andre Marceau is found strangled to death in the middle of a freshly rolled croquet lawn. His dying words are "The Babe from Hell!" The only footprints, other than Marceau's own, are some tiny, baby-sized footprints. These do not lead out to the body but merely describe a small arc around it. No wonder the police suspect a Flying Stranger-Baby! Keeler supplies several handsome maps of the scene of the crime.

To all appearances, X. Jones is an "impossible crime" story of the type then popular, one in which the reader is challenged to solve the puzzle through deduction. I would bet that very few readers guessed this one.

The culprit is Napoleon Bonaparte. It turns out that Napoleon seduced an ancestor of the victim and passed on a (hypothetical) gene that causes people to die suddenly with symptoms that medical examiners cannot distinguish from strangulation asphyxia. The same gene also causes hallucinations -- in the victim's case, of a demonic baby.