`The Adventure of the Cardboard Box' was written in 1893, but Sir Arthur Conan Doyle left this case out of many versions of the second collection of cases of Sherlock Holmes, The Memoirs of Sherlock Holmes.
Holmes is called on the case by Inspector Lestrade, who was contacted by Susan Cushing because she received a gruesome packet in the mail. Ironically, it was not the gruesome nature of the packet but the inference behind the crime that made this case controversial.
Doyle hinted at adultery early on in the case, when Sherlock Holmes used a painting of Henry Ward Beecher to deduce the thoughts of Dr. Watson. Beecher was the pastor of the Plymouth Church in Brooklyn Heights who was involved in a highly publicized trial for adultery in 1875. Beecher was also a notable abolitionist whose sister, Harriet Beecher Stowe, wrote the novel Uncle Tom's Cabin.
Readers may notice the same anecdote in `The Resident Patient' of The Memoirs of Sherlock Holmes. The original version of The Resident Patient published in Strand did not contain the Gordon/Beecher anecdote. When Doyle decided that the Cardboard Box was too controversial for younger readers, he omitted the case in The Memoirs and wove the anecdote into the version of 'The Resident Patient' that was published in The Memoirs of Sherlock Holmes.
Holmes used the tarred twine and knot used to secure the package, as well as the course salt used as filler, to deduce the nature of the criminal. There was also something in the profile of Susan Cushing, the lady who received the gruesome packet, which helped Holmes discover a detail regarding the contents of that package.
The inference of adultery becomes clear when one reads the testimony of Jim Browner to Inspector Montgomery, furnished at the end of the case. `The Cardboard Box' is the second case of the eight cases published in His Last Bow, a collection of Sherlock Holmes short stories published in 1917.