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The Adventure of the Cardboard Box is one of the 56 short Sherlock Holmes stories written by Sir Arthur Conan Doyle. It is the second of the twelve Memoirs of Sherlock Holmes in most British editions of the canon, and the second of the eight stories from His Last Bow in most American versions. 

Miss Susan Cushing of Croydon receives a parcel in the post that contains two severed human ears packed in coarse salt. Inspector Lestrade of Scotland Yard suspects a prank by three medical students whom Miss Cushing was forced to evict because of their unruly behaviour. The parcel was sent from Belfast, the city of origin of one of the former boarders. Upon examining the parcel himself, Holmes is convinced that it is evidence of a serious crime.