What a remarkable thing an artist can accomplish in 45 minutes — that’s among the upshots of “Sherlock Jr.” (1924), a film that will be featured for the next two weekends at the Museum of the Moving Image as part of its continuing series “Silents, Please!” Buster Keaton’s rumination on love, cinema, and the love of cinema grows in stature with each passing year. It’s an ingenious film that leaves a poetic afterglow.

Forty-five minutes is an illusion in terms of the creative process. The making of “Sherlock Jr.” went over-schedule, from some accounts twice as long as was Keaton’s norm. Part of this can be traced to physical distress suffered by its leading man. Being thrown from a moving motorcycle was the least of Keaton’s problems. A scene involving a rail-line water spout left him unconscious and prone to severe headaches. X-rays later disclosed that Keaton had broken his neck during the stunt. The auteur could not be daunted.

The primary reason “Sherlock Jr.” took more time than usual in the making was because of its cinematic trickery. Keaton was a tinkerer and became fascinated by the properties and possibilities of the camera upon first stepping onto a movie set. The short comedy “The Playhouse” (1921) is a case in point: Through elaborate staging and precision timing, Keaton confabulated a film in which he played myriad parts, all of whom appeared on the screen simultaneously. Watch it on YouTube and tell me this 100-year-old movie isn’t breathtaking in its seamlessness. Take that, CGI.

The moment in “Sherlock Jr.” much beloved by cineastes is when Keaton’s character — we know him only as “the projectionist” — falls asleep on the job, whereupon a ghostly doppelganger ascends from his corporeal form. Leaving the projection booth, Keaton strolls down the aisle of the theater and steps into the film. Once inside the movie, the background shifts repeatedly, leaving our hero to contend with an array of radically different contexts: a rocky cliff, a city street, and a den of lions. Surrealism with pratfalls, here it is.

“Sherlock Jr.” begins on a relatively straightforward basis: Keaton is a hard-working, if ineffectual, yob eager to court Kathryn MacGuire. The trouble is that our projectionist has competition for the fair maiden’s hand: a towering, gangly, and patently unscrupulous Ward Crane, here playing “the Local Sheik.” After some expert slapstick involving a pile of rubbish and dollar bills, Keaton buys “the girl” a box of chocolates. Not to be outdone, the Sheik buys a bigger box of chocolates, an item he can afford only because he’s stolen and pawned the watch of the lady’s father (Buster’s real-life father, Joe Keaton).

After Keaton is framed for the crime he returns to the theater and walks into the movie. Whereupon he is transformed into the crisply attired Sherlock Jr., a master criminologist out to solve a mystery with circumstances similar to those he’s undergoing in the real world. The set pieces that ensue — a dangerous game of pool, masquerading as an old woman, and the transformation of an automobile into a sailboat — are precisely calibrated, astonishingly executed, and, lest I forget, very funny.

Yet it is the ending of “Sherlock Jr.” that encapsulates everything that makes Keaton special. The boy gets the girl; that’s as it should be. But neither of our leads knows what to make of the emotions they are experiencing or how to put them into motion. 

At a loss, the projectionist takes cues from the film that’s currently unspooling in the theater, a romantic period drama. Here is Keaton’s greatest special effect: the acknowledgment of both the power and limitations of cinema, exquisitely timed and genuinely sweet. Not even Sherlock Jr. can fathom the power of love without a leg up.