Something most of us probably don’t know about Sherlock Holmes: his first long-term theatrical incarnation made his bow in the role in Buffalo in 1899. Yes, Buffalo.

The actor’s name was William Gillette and, except for one very brief Holmes play in Glasgow five years earlier, Gillette’s rendition of Holmes on stage came before everybody else’s.

And now we have Robert Downey Jr. as a singularly funky and Bohemian version of Holmes. He seems to disdain soap when not working, keeps his crib at 221 B Baker Street very untidy and likes to test his pugilistic skills in sweaty outlaw bare-knuckle fights against opponents 50 pounds heavier.

This Holmes can’t actually play the violin, he just plucks it like a ukulele every now and then when he’s bored — or thinking. When he’s really bored, he shoots the walls of his rooms or crawls on all fours across the floor. If he weren’t visibly titillated by proximity to Irene Adler (played enticingly by Rachel McAdams), you’d guess gay overtones to his relationship to Jude Law’s Dr. Watson, especially his jealousy at Watson’s announced plans to marry a beautiful and spirited young woman (played by Kelly Reilly who responds to Holmes’ rudeness at dinner with a full glass of red wine emptied on Holmes’ cheekbones at high velocity.)

But there’s a case afoot. There always is.

This time, it’s about a serial killer named Lord Northwood (Mark Strong, hair slicked down like Max Schreck in F. W. Murnau’s “Nosferatu”), who comes back from the dead after being hanged. And when all is said and done, proves to be bent on world domination.

There are lots and lots of Bondian action sequences, all taking place in a filthy, gray unhealthy version of Victorian London. Though there’s no actual horse dung shown on camera, the way director Guy Ritchie films the place, you’ll swear you can smell it on the screen.

To be blunt, it seems to me this movie should have been a lot more fun than it turns out to be. Here is yet another dumb-down current film version of some supreme intellectual of yore on film who is turned into a breathless James Bondian action master to keep 12-year-old boys everywhere happy. (For the definitive idiocy in this manner, see Hugh Jackman as “Van Helsing” in which “Dracula’s” wise, scholarly vampire fighter turns into a super hero in chaps.)

I’m fine with revisionist burlesque of oft-filmed movie characters. What Robert Altman and Elliott Gould did to Philip Marlowe in “The Long Goodbye” is far more disrespectful than what Downey and Ritchie do to Sherlock Holmes here. It was also a lot more impudent and radical fun too.

This is largely mechanical pseudo-Bond entertainment from the British Isles. A sequel is practically assured, despite the near-universal lack of standing ovations.

For those who might wonder if Ritchie gets in any sly underground digs at ex-wife Madonna, carefully note that the secret texts of the would-be world-dominating secret society are written, in part, in Hebrew. And then remember that Madge is, among other things, a devotee of the study of Kabbalah, the mystical part of Judaism.

Such is this movie that even a secret dig at the director’s ex doesn’t seem as much fun as it ought to be.

SHERLOCK HOLMES

Two and a half stars

STARRING: Robert Downey Jr., Jude Law, Mark Strong and Rachel McAdams

DIRECTOR: Guy Ritchie

RUNNING TIME: 128 minutes

RATING: PG-13 for thematic material including violence.

THE LOWDOWN: Holmes fights a secret society bent on world domination.