One of the real treasures from the Pre-Code Era, “Red Dust” (Metro, 1932), is quite possibly the raciest picture Metro ever released during the twenty-seven years that Louis B. Mayer ran the place — I can’t think of another that even comes close. Clark Gable plays Dennis “Fred” Carson, the hard-driving, hard-drinking, womanizing overseer on a rubber plantation in Indochina. Harlow plays an on-the-lam whore named Vantine, who fetches up at the plantation one night. Here’s how they meet.

The passed-out drunk is Donald Crisp, cast against type: in this one, he’s a thoroughgoing swine. He’s not very good in the part, but it’s a relief to see him do something different from the insufferably dignified gentlemen he usually played. Gable’s partner, McQuarg, is played a fine old character actor named Tully Marshall.

Before I saw “Red Dust” for the first time, I never really understood Harlow’s appeal. In “Dinner at Eight,” for instance, the dumb broad she plays is so spoilt and bad-tempered and shrill, I find her far more irritating than amusing. (It doesn’t help that most of her scenes are with horrible Wallace Beery.) But she’s tremendously appealing and funny in “Red Dust,” and she steals every scene she’s in. In his own quiet way, however, Tully Marshall in this next scene gives her a run for her money. (Willie Fung is the racist cartoon of a houseboy. The ugly Asian stereotypes in “Red Dust” are pretty breathtaking by today’s standards.)

Whenever I’m in a bad mood, Tully Marshall’s performance — especially his reading of “If it was the summer of eighteen hundred and ninety-four, I’d play games with you, sister” — is always enough to chase the blues away. Marshall is the sort of old pro that makes me love old movies. Two years before he made this picture, he appeared with John Wayne in Raoul Walsh’s “The Big Trail,” which was shot in Mexico. During the shoot, Wayne was afflicted with a dose of la turista so terrible that he lost eighteen pounds in a single week; for the rest of his life, the memory of that awful week made him shudder involuntarily. When he was well enough to return to work, the first scene he shot involved Tully Marshall and a big jug of liquor. He entered with Marshall slung over his shoulder. According to Wayne, “I set him down and we have a drink with another guy. They passed the jug to me first, and I dug back into it. It was straight rotgut bootleg whiskey. I’d been puking and crapping blood for a week and now I just poured that raw stuff right down my throat. After the scene, you can bet I called him every kind of an old bastard.” Despite his notoriety as a world-class booze-hound, Marshall was in constant demand; he appeared in almost two hundred pictures, including “Ball of Fire” and “Grand Hotel.” Every time I see him, I think of how the old soak and his jug of San Juan possum juice almost turned “The Big Trail” into “The Last Run” for young Duke Wayne. Over the past year, it has become abundantly clear to me that good supporting performances like Tully Marshall’s are very often what I like best about the pictures that give me the most pleasure.

But in this particular case, it’s Harlow who owns the picture. Her combination of vulgarity, street smarts and sunny good-nature has never been surpassed. Like so many movie stars of the Studio Era (and unlike so many of today’s stars), her voice is as unmistakable as her face, but it’s also notable — especially for that era — for its foghorn ugliness. The advent of talking pictures ruined the careers of so many Silent Era glamour queens, yet Harlow’s career didn’t really take off until audiences got a load of the strident clamor that issued from her milk white throat. She rarely sounds perfectly natural — overemphasis and sing-song are two hallmarks of her vocal style — but her commitment to the material is absolute; her facial expressions and body language are so spontaneous and lively that her overtly artificial vocal mannerisms work in her favor (at least, they do in “Red Dust”). In her scenes with Gable, she’s clearly acting — putting on a show — but she’s not acting for us: she’s showing off for the guy she’s trying to hook. Look at how deftly she warms him up and wins him over in this next scene. He’s irritable and she’s exhausted, but she’s so attracted to him that she can’t stop flirting. The more she chatters, the madder he gets, but the more violently he tells her to shut up, the hornier she becomes — she’s impossible to insult. His steely hostility hasn’t a chance against her saucy vivaciousness. She and Gable make a brilliant team, but she’s the one who drives the scene, and she does it with great wit and verve.

This next clip is the best-known scene in the picture: Harlow takes a bath in a rain barrel. She did it topless. We don’t get a peek, but Gable sure did. At one point between takes, she stood up, gave the crew below a good look and said, “This is for the boys in the lab!” The film never left the set, however: Victor Fleming had it removed from the camera. He didn’t want it to turn up on the black market.

“Red Dust” certainly looks like a Metro high-gloss picture of the era: the glamorous lighting for Gable and Harlow, the familiar indoor jungle settings and the backlot shores of Metro’s Lot One Lake (where the early Tarzan pictures were shot) — everything about its look is unmistakably Metro. But it sure doesn’t act or think like a high-gloss Metro picture. The randy banter between Gable and Harlow is breezy and fun-loving, not passionate and earnest — and their complacence about sex is completely at odds with Metro’s fastidious primness. In fact, I can’t think of another American picture of its era in which adult sexuality, promiscuity and marital infidelity are treated with such buoyant nonchalance. Before the picture’s over, jealousy will lead to gunfire, but nobody gets killed or is even seriously hurt. The whole point of view is radically different from Metro’s strict moral code. In this picture, Gable has sex with Harlow the day they first meet; he carries on with her for a month, and when he’s ready to try a new flavor, he gives her a big wad of cash, slaps her on the ass and puts her on the boat back to Saigon. Then he promptly forgets about her — until her boat runs aground and she comes back for more. But when Harlow returns, Gable’s already busy seducing his new employee’s wife (Mary Astor), and treats Harlow badly. Gable carries on with Astor until he discovers that her husband (Gene Raymond) is a decent guy. Angry with himself and disgusted with her, he sends her back to her husband and tells them both to get lost: “You two pack your tennis racquets and go back where ya belong.” It’s hardly what one expects from Metro-Goldwyn-Mayer. And through it all, we root for Gable. It’s not only the sexiest picture Metro ever made, it’s also the most subversive.

There’s something else that sets the sexuality in “Red Dust” far apart from other pictures of its era: sex looks like a lot of fun. Garbo, John Gilbert, Joan Crawford, Jack Barrymore and all the other famous screen lovers of the era made lust look horrible and serious — their idea of wantonness looks like my idea of a hanging judge as he pronounces sentence. But there’s nothing brooding or terrifying about the sexiness in “Red Dust”: it’s happy and fun; it’s a romp. Lust doesn’t make Gable, Harlow and Astor frown and smolder, it makes them light of heart and full of laughs. Me too.