Final answer:
Julia Stoner's final words in Doyle's mystery were 'Oh, my God! Helen! It was the band! The speckled band!' They are crucial for Sherlock Holmes to solve the case in 'The Adventure of the Speckled Band', pointing to the true nature of the murder weapon.
Step-by-step explanation:
In the mystery novel by Sir Arthur Conan Doyle, the final words of the character Julia Stoner, the murder victim, were: 'Oh, my God! Helen! It was the band! The speckled band!' This declaration occurs in one of Doyle's most famous Sherlock Holmes stories titled 'The Adventure of the Speckled Band'.
The story is a classic locked-room mystery, a subgenre of detective fiction. Julia Stoner's last words are a critical clue that leads the astute detective, Sherlock Holmes, to solve the case. The phrase 'the speckled band' is the pivotal hint that eventually connects to the method and the perpetrator of the crime, which is ultimately revealed to be an exotic snake owned by Dr. Grimesby Roylott, Julia's stepfather, whom she was referring to indirectly.
The enigmatic phrase is an excellent example of Doyle's use of red herrings and narrative misdirection, common elements in mystery fiction. It incites the reader's curiosity and misleads both the protagonist and the reader before the truth is uncovered. Such details enhance the engagement with the text and prove Doyle's mastery of the mystery genre.