Excellent news: Your X-rated Sherlock/Watson slashfic now has the blessing of the American legal system!
Well, sort of. A US district court has ruled that, with the exception of a few stories published after 1923, the material from Arthur Conan Doyle’s Sherlock Holmes series is in the public domain.
A New York Times article from earlier this year reports on the details of the legal battle—some of which are more sordid than you might guess (“a prominent Holmes scholar who was found garroted with a shoelace shortly before a controversial auction of Conan Doyle papers”?!).