On Dec. 28, 1885, London grocer Edwin Bartlett was discovered dead in his bed. In his stomach was a fatal quantity of chloroform, but, strangely, his throat and larynx showed no signs of the burning that liquid chloroform should have caused.

Bartlett’s wife, Adelaide, was having an open romance with George Dyson, a local minister. It transpired that she had induced him to buy chloroform at local pharmacies in quantities too small to provoke suspicion, ostensibly to help treat Edwin, who was undergoing painful dental surgeries.

At trial, Adelaide’s defense was simply that she had no way to get the chloroform into Edwin’s stomach without passing it down his throat. The jury let her go.

“Now that Mrs. Bartlett has been acquitted,” remarked pathologist Sir James Paget afterward, “she should tell us, in the interests of science, how she did it.” Adelaide made no response. The puzzle of Edwin’s death has never been solved.