By the early 1950s, the screwball generation, and the first generation of sound actors, were starting to come of age. Few films captured that generational shift quite as acutely as Monkey Business, which plays as a late riff on Bringing Up Baby, one of the most iconic releases of the screwball era. Both films star Cary Grant, both films were directed by Howard Hawks, and both films revolve around an animal that rehabilitates a relationship. In Bringing Up Baby, that animal was a leopard named Baby, and in Monkey Business it’s a chimp named Esther.

This time around, Grant plays Barnaby Fulton, a scientist who is experimenting on an elixir of youth. His wife Edwina, played by Ginger Rogers, feels his work is putting a strain on their relationship, while his boss Oliver, played by Charles Coburn, is keen for results. Barnaby and Ginger have no children – the youngest person in the film is Oliver’s assistant, Lois Laurel, played by Marilyn Monroe, who represents the post-screwball generation. When Esther the chimp escapes from her cage, discovers the elixir, and pours it into the laboratory tank, chaos ensues as Barnaby, Edwina, Oliver, and then both Barnaby and Edwina, revert to their youths.

Before we get to the elixir, however, Monkey Business seems curiously and deliberately unformed. Like Barnaby’s progress on the elixir, the film only seems 23% there, forcing Hawks to break the fourth wall in the opening scenes to emphasise the staging and layout of the action. As the credits roll, we see Barnaby open a door a couple of times, and each time Hawks instructs him to wait – “Not yet, Cary!” When Barnaby (or Cary) finally walks through his door, there’s a subliminal shift from non-diegetic to diegetic space, as Edwina, like Hawks, instructs him how to handle the mise-en-scene that unfolds before him (and us). She gives him a series of precise instructions about how to move, stand and look, playing the role of director herself.

The screenplay also feels curiously unformed during this first part of the film. Barnaby continually gets words wrong, miscalculates simple mathematical problems, and pauses, mid-thought, for phrases that never quite come to him. He wears thick glasses, but they seem to impede his vision, and narrow his focus, so that he’s always squinting at everything. He also has bad bursitis in one arm, which gives every scene an off-kilter awkwardness as he rehearses different positions to figure out the most comfortable posture and body language.

In other words, Hawks paints Barnaby and Edwina as a middle-aged screwball couple. Their dialogue exhibits the same cross-purposes and conversational play as classical screwball films, but it’s now milder, slower and closer to absent-mindedness: “the language is confusing, but the actions are unmistakeable.” The hesitant tone of this opening scene is enhanced when we find out that they were both on the cusp of leaving for a party, but decided to stay home when Barnaby was hit by a flash of scientific inspiration. Last time they stayed home, Edwina recalls, it was for carnal reasons, not for intellectual reasons. Nevertheless, there’s still some residual screwball synergy here. When Edwina heats up some soup for Barnaby, it sparks an idea about how to use heat for the elixir formula, which briefly heats up their romance too.

Even so, you feel that this screwball couple needs a reboot – and that the film needs a burst of energy to become fully-formed as a screwball vehicle. This is where Esther, the monkey, comes in. In chemistry, an ester is a reactive compound, and Esther plays a similar role here, driving all the major plot points after she discovers the elixir, and introduces it into the laboratory drinking supply. She’s a monkey ex machina – and the film is fascinated by the monkey in the machine, by our own inner monkey. Only by completely reverting to a simian body, Hawks suggests, can these two characters hope to recapture their screwball heydays.

Barnaby is the first person to take the potion, and it immediately restores his sex drive, along with his lust for life. He describes the first symptoms as “a sensation not unlike a series of small electric shocks – a sensation of extreme wellbeing.” Minutes later, he’s revelling in the word games, double entendres and cross-purposes of classic screwball – and at the pace of classic screwball. He also exhibits the sensuous curiosity of screwball, especially when it comes to Lois, his secretary. In an earlier scene, Lois told Barnaby that she was using one of his patented non-tear stockings, and showed him her legs to prove it. Back then, Barnaby only had eyes for the fabric, but after the elixir he notices her legs in a new and enhanced manner.

It’s not just Lois’ legs that Barnaby sees either – it’s the whole world. As soon as the elixir takes full effect, Barnaby develops 20/20 vision, and discards his glasses. All of a sudden, the film also feels fully awake, fully visualised, fully available for our own eyes. Conversely, at this moment, you realise that the film was half-realised, half-awake, half-there, when nobody was on the elixir. The scenes without elixir tend to be underlit, especially when it’s just Barnaby and Edwina – one of them is always reminding the other to turn on the light – whereas the elixir scenes all take place during the day or in rooms and spaces suffused with artificial light.

Taking the elixir thus restores the pleasure of sight and the pleasures of cinema. Rather than simply go to the movies, Barnaby takes Lois out on a joyride, treating the windscreen as an augmented cinema screen as they embark on one zany escapade after another. In Pursuits of Happiness, Stanley Cavell notes that classic screwball comedies typically had a pastoral interlude, in which the main couple retreated to the country (usually New England) to restore their relationship. Two decades later, we have a suburban interlude more than a pastoral interlude, as Barnaby and Lois chart a crazy circular motion around their local neighborhood, taking in all the thrills suburbia has to offer, from roller skating to diving in a municipal pool.

During these scenes, the pastoral interlude also becomes a more literal pastoral interlude, as Barnaby and then Edwina take on different 30s cinematic modes, quickly expanding out beyond screwball to musical and slapstick comedy. These scenes often pre-empt the mid-life crisis as a later category of middle-aged experience, especially in Grant’s joyrides. Like a generation of boomers who reached middle age in the 90s, he gets a new haircut, buys new clothes, buys a new car, and turns his eye upon younger women to restore his vanished youth.

This refracted and condensed recourse to 30s cinema is most acutely embodied by Edwina, who accidentally ingests the elixir shortly after it wears off on Barnaby. Like Barnaby, she is suddenly struck by the pleasures of watching. Whereas he buys a new car, she spontaneously suggests driving it all the way to La Jolla, where they spent their honeymoon together. She starts the engine before he gets in, and frequently takes her hands off the wheel to gesticulate frantically. Edwina also reverts to a classic screwball persona – an eccentric ichthyologist – again recalling the many convergences of animal and human movement in these comedies.

Yet Edwina also goes beyond screwball to embody slapstick and musical comedy. As the potion starts to take effect, she removes a fish from a laboratory beaker, and puts it down Oliver’s pants, causing him to shudder mechanically, like Chaplin or Keaton. When he finally makes his way to a seat, Edwina puts a pie on it, now recalling Laurel and Hardy more than the mechanised comedy of Chaplin or Keaton. Her own mechanised movements almost turn the film into a musical at this point, especially since there’s virtually no soundtrack until the potion takes hold. Even when she and Barnaby arrive at La Jolla, at 11pm, and they’re making their way to the honeymoon suite, she drags him to the dance floor, where they replay and reconsummate their wedding night before the potion wears off just as they reach their room.

This leads to the central comic bind of the film – both Barnaby and Edwina are sensorily deprived in their marriages, and both of them need the elixir to restore the marriage, but their use of the elixir doesn’t initially cross over. Nor can they make proper use of the elixir – it wears off on Barnaby as he’s driving home after his joyride, and it wears off on Edwina as she arrives at the honeymoon suite. As a result, some of the best comic sequences come when these characters are transitioning out of the elixir. As their youth subliminally decelerates, they return, wilting, to a renewed sense of middle age, and a more exhausted late screwball. For Barnaby, the warning signs come when he doesn’t quite land a swan dive, and opts for an old-timey song on the radio; for Edwina, when she becomes distracted from the honeymoon suite by memories of her mother, who disapproved heavily of the marriage.

When Barnaby and Edwina come off the elixir, the film grows more sensorily deprived too – all of a sudden, you have to squint your eyes and strain your ears to fully process it. While the elixir certainly restores youth, it also intensifies the disorientation of middle-age when it wears off, meaning the film feels a little less formed each time Barnaby and Edwina come down. This doesn’t just disorient the person coming off the elixir, but the other party, and the audience. When Edwina starts to wilt in the honeymoon suite, Barnaby is just as confuddled, since she takes his glasses, and then traps his robe in the door, forcing him to wait, blind, in the corridor, before finally wrenching himself free, and stumbling down a huge laundry chute.

When they do finally take the elixir together, in the third act, the couple actually regress back beyond the screwball era, as Edwina reverts to a toddler, and Barnaby reverts to an ape. At this point, Monkey Business becomes a cautionary tale, warning us that any attempt to return to the screwball past is not just futile but downright dangerous. Screwball now turns manic-demonic, as Hawks creates a truly cacophonous wall of sound, in a kind of double-edged gesture. On the one hand, this certainly serves as a warning about trying to regain the screwball past, but it also feels like Hawks is desperately attempting to recapture the visceral thrill of sound cinema, so central to the screwball project, two decades into the sound era.

What ensues is a kind of exhaustion of screwball – a reduction of screwball to a chaotic and cacophonous sonic field. We start with Esther, who’s tickled under the boardroom table, and responds by throwing lights bulbs off the boardroom chandelier. We then proceed to a paint fight between Edwina and Barnaby, who diverge into their own manic trajectories. Finally, Barnaby comes across a group of children playing Cowboys and Indians, and rallies them to scalp Edwina’s ex-lover, who comes into the picture late in the piece as a corrective to all this inane screwball energy. Barnaby teaches the children a war dance, a nonsensical and caricatured series of abstract sounds that escalates and escalates, drawing all the cacophony of the film into its centrifugal pull, until it collapses in on itself, and the elixir finally wears off.

By this point, Barnaby, Edwina and the film have realised that “you’re only old when you forget you’re young,” assuring us that screwball is a state of mind as much as a historical era. Yet the presence of Marilyn, as Lois, works against this reassurance, and leaves the film with an underlying anxiety. She’s the only character who doesn’t take the elixir, and yet she seems a perfect candidate for it, given how entertaining she is when Barnaby whisks her up into his joyride. That alone would make her an embodiment of the post-screwball generation that the film fears, even if Marilyn herself didn’t usher in a new wave of actresses – blonde bombshells who simply weren’t permitted to luxuriate in the wit, panache and overt intelligence of their screwball ancestors. And the paradox of Monkey Business is that the more it tries to contain Marilyn, the more her post-screwball charisma shines through, as the film affirms the end of screwball almost despite itself – presumably why it feels so unrealised right until the very end.