Mortimer presents Holmes and Watson with a manuscript which the always observant Holmes had already noticed and dated at 1730. The document, dated 1742, Baskerville Hall, reveals the myth of the Baskerville curse. At the time of the "Great Revolution," Mortimer reads, Hugo Baskerville lorded over the Baskerville mansion in Devonshire. Sex crazed and lecherous, the infamous Hugo became obsessed with a local yeoman's daughter, whom he kidnapped one day. Trapped in an upstairs room, hearing the raucous drinking and carousing going on downstairs, the girl escaped with the help of an ivy-covered wall. She fled across the expansive moorlands outside. Enraged at finding that his captive escaped, Hugo made a deal with the devil and released his hounds in pursuit of the young girl. Hugo's companions had followed their drunken friend across the moorland, and came upon the bodies of both Hugo and his girl. Hugo had just had his throat ripped out by "a foul thing, a great, black beast." Ever since, Mortimer reports, the supernatural hound has haunted the family. The hound just recently killed Sir Charles Baskerville, the latest inhabitant of Baskerville Hall.
Mortimer unfolds the Devon County Chronicle of May 14, reading about Sir Charles' philanthropy and the circumstances surrounding his death. Having remade his family fortune in South African colonial ventures, Charles returned two years ago to the family estate and gave extensively to the local population. The chronicle mentions the myth only to discount it, citing the testimony of Sir Charles' servants, Mr. Barrymore and Mrs. Barrymore, and that of Mortimer himself. Charles was found dead, the paper reports, at the site of his nightly walk down the so-called Yew Alley, which borders the haunted moorlands. Suspicious facts include Charles' apparent dawdling at the gate to the alley, and his footsteps down the alley itself, which indicated tiptoeing or running. But the paper points out Charles' poor health and the coroner's conclusion that the man died of a heart attack. The article goes on to insist that the next of kin, Sir Henry Baskerville, should come to take his uncle's post and continue his philanthropy.
Mortimer interrupts the account, however, to indicate that those are the publicly-known facts. Off the record, he admits that Sir Charles' poor health was a result of his fear of the family curse, and that he himself had suggested a sojourn in London to ease Sir Charles' nerves. Finally, Mortimer announces that the scene of the crime contained, in addition to Sir Charles' tiptoeing steps, "the footprints of a gigantic hound."
The curse of the Baskervilles establishes many of the themes that will run throughout the rest book—the contrasting pairs of natural and supernatural, and myth and reality. Even as Doyle relates the deeds of a lecherous libertine—in the tradition of the Marquis de Sade—he invokes the Gothic tradition that is popular at the time. The ideas of an ancient curse, a hound of hell, and a kind of divine retribution all recall stories like those of Edgar Allan Poe, who imagined the most macabre situations and the most otherworldly explanations.
This chapter also presents several sources of information about the case—the manuscript, the paper, and Mortimer's reading of each one make it difficult to know which source to believe. An ancient curse, a modern piece of journalism, and a doctor's counsel all conspire to bewilder the detectives and the audience. Ultimately, however, the interplay of multiple perspectives only serves to emphasize the accuracy of our original source of all knowledge: Sherlock Holmes himself. Each source is set against the master's logical techniques for gathering and analyzing clues, both in form and in function.
The manuscript is notable both for its tone, which is radically different from the novel's no-nonsense, direct tone, and for its content, which points to the easy, but unrealistic, supernatural answers to a perplexing problem, rather than the more complicated scientific explanations. In the final analysis, Holmes is able to gleam the valid facts from what would otherwise be a shadowy, ancient myth. Dating the document at 1730, and analyzing the print and the paper, Holmes brings the elusive myth into his realm by using the careful deductive reasoning.