These entries are crucial to the plot for several reasons:
* They introduce the legend of the hound: Sir Charles's entries detail the history of the Baskerville family and the curse of the hound, setting the stage for the mystery.
* They reveal Sir Charles's fear: His entries show his growing terror, making him a more sympathetic character and adding to the suspense.
* They provide clues for Holmes: The entries contain details about Sir Charles's activities and observations that help Holmes piece together the events leading to his death.
The entries are presented as primary source material within the story, giving the reader a glimpse into the mind of the victim and the nature of the threat. This allows Doyle to create a sense of authenticity and immerse the reader in the world of the story.
Instead of simply telling the reader about the legend and the fear, Doyle shows it through the lens of the victim's own words, making the story more impactful and engaging.