NEW YORK, NY.- One moment I am sprawled on a couch in my New Jersey home, lost in another classic old movie. The next, I am falling through the floorboards and tumbling like Alice into the wondrous unknown, only to land in a bunkerlike government structure built into the side of a Virginia mountain.

Yes, I had gone down a rabbit hole, down into the black-hole past. As I plummeted, I learned about “lost” movies, an unlikely box office star, a secure facility where national memories are stored — and a silent film whose comic Irish stereotypes once caused uproars in theaters.

Follow me down, why don’t you?

My descent began as I watched “Dinner at Eight,” a 1933 classic featuring several early MGM luminaries, including Marie Dressler, a stout actor in her early 60s whose impeccable timing and weary resilience had made her the biggest star in Hollywood. Depression-era audiences adored her, sensing that she, too, knew hard times. And she did.

Wanting to know more about Dressler, I opened my laptop and down the hole I went. I learned that Dressler’s success had come after decades of triumph and travail. By 1927 she was nearly broke and considering a housekeeping job when a dear friend, the celebrated screenwriter Frances Marion, offered Dressler a lead role in her next picture: “The Callahans and the Murphys,” a silent comedy so controversial, I read, that it was yanked from circulation and is now considered lost.

Wait. What?

I am a first-generation Irish American who is fairly steeped in the reflections of me and mine in popular culture — from the simian Irish caricatures of Thomas Nast to Christopher’s nightmare in “The Sopranos” that hell is an Irish bar called the Emerald Piper. But my ignorance of “The Callahans and the Murphys” sent me deeper into the well of curiosity.

The plot, I learned from news accounts and MGM records, centered on two tenement Irish families in a place called Goat Alley, where, a title card explained, “a courteous gentleman always takes off his hat before striking a lady.” Mrs. Callahan (Dressler) and Mrs. Murphy (Polly Moran) are quarreling friends with large, commingling broods; the Callahans’ daughter is dating Murphy’s bootlegger son. There are fleas and chamber pots and thumbed noses and a St. Patrick’s Day picnic that — hold on to your shillelagh! — devolves into a drunken brawl.

Released in June 1927, the comedy initially received encouraging reviews, with several critics singling out Dressler’s performance. Her career now revived, she would go on to win the hearts of America — and an Academy Award for best actress (for her role in the 1930 comedy-drama “Min and Bill”) — before dying at 65 in 1934.

But several Irish American organizations lodged complaints about the depiction of Irish life as one long, intoxicated slugfest. MGM blithely defended the film as good-natured fun, only to realize that an intractable Hibernian grudge was taking hold, as this internal studio telegram reflects:

VARIOUS IRISH SOCIETIES HAVE BEEN COMPLAINING DURING LAST WEEK TO VARIOUS BRANCH OFFICES REGARDING NATURE CALLAHANS MURPHYS — STOP — OBJECTIONS NOW HAVE REACHED STAGE WHERE WE MUST DO SOMETHING MEET THEIR DEMANDS.

Worried about its investment, MGM made several cuts and changes to stem the growing outrage among the country’s Irish Catholics — who, it should be noted, already felt under attack by a resurgent and powerful Ku Klux Klan that mocked their faith and questioned their patriotism.

References to Goat Alley and domestic-violence etiquette were cut. No more fleas, either, or comical renderings of the Catholic sign of the cross. And a lot less drinking.

In addition, a title card was added to share the malarkey that the Callahans and Murphys represented the “fast-fading old school families to whom the world is indebted for the richest and rarest of wholesome fun and humor.”

In one desperate public-relations gambit, MGM all but announced that some of its best friends were Irish. Did you know that Marie Dressler had Irish blood on her mother’s side, and had given to Irish causes and Catholic charities? And that her co-star Polly Moran was of fine Irish stock?

By now, Irish eyes weren’t smiling; they were crossed.

Across the country, pressure from Irish newspapers, elected officials and Catholic clergy forced the film’s cancellation. In New York City, moviegoers threw lightbulbs and stink bombs. In one case, a man stood up and shouted, “My mother never acted like that!”

The objections of Cardinal Dennis Joseph Dougherty, the no-nonsense archbishop of Philadelphia, finally forced MGM to surrender. In the fall of 1927, just a few months after the film’s promising premiere, the studio issued an order by telegram to “withdraw ‘Callahans and Murphys’ from circulation immediately.”

With that, “The Callahans and the Murphys” was shelved, destined to be remembered, if at all, as a foreshadowing of the movie industry’s stringent Production Code of standards, later to be zealously enforced by an Irish Catholic, Joseph Breen. Intended to ensure morally acceptable moviemaking, the code’s long list of prohibitions would include homosexuality, interracial relationships, adultery and overly passionate kisses.

“The Callahans” is “legendary” among film scholars, said Farran Smith Nehme, a critic and historian (and Marie Dressler fangirl). “There’s really only been a handful of films that, instead of simply being edited, were pulled altogether because they were considered offensive.”

My free fall continued. I learned that the negatives for “The Callahans” were probably destroyed, that no complete print is known to exist and that it is just one of many thousands of so-called lost films.

To find out more, I contacted David Pierce, a film historian and preservationist at the Library of Congress, who told me that of the nearly 11,000 features released in the United States before 1930, only about 25% have survived in any complete form. “And they’re not necessarily the 25% you want to see,” he said.

The reasons are many. The nitrocellulose — or nitrate — used at the time as a base for filmmaking was quick to decompose and highly flammable; fires were not uncommon. What little worth silent films had after their run vanished with the advent of sound in the late 1920s. Prints were often stripped of their silver content and junked.

Indifference also played a role. Studios tended to categorize movies as business widgets with finite shelf lives, rather than as cultural works deserving of posterity. “By 1935, nothing had less value than a silent movie,” Pierce said.

But the Library of Congress is the keeper of American memory. Its immense collection contains more than 178 million books, manuscripts, recordings, maps, photographs and moving images — including a two-minute trace of “The Callahans and the Murphys.”

Would I like to see it?

So deeper I fell, until finally bottoming out in the foothills of the Blue Ridge Mountains, on the outskirts of Culpeper, Virginia.

Here, in the late 1960s, the federal government built an underground facility into the side of Mount Pony, about 75 miles southwest of Washington, as a secure storehouse for billions of dollars in cash in the event of nuclear war. Responsibility for the structure was eventually transferred to the Library of Congress, expanded and repurposed as the National Audio-Visual Conservation Center, with nearly 90 miles of shelving.

Stored in the side of this mountain are four million scripts, posters, photos and other ephemera; four million sound recordings; and two million moving-image items, including about 140,000 cans of nitrate films kept in specially designed vaults where the temperature is kept at precisely 39 degrees. The vaults are divided by studio and nonstudio films: in one section, Columbia Pictures (say, “It Happened One Night”); in another, Universal Pictures (“Abbott and Costello Meet Frankenstein”).

“It is meant to be a comprehensive representation of American cinema,” said Pierce, the center’s assistant chief and walking film encyclopedia. “It is not our goal, and we don’t have the space or the staff, to collect absolutely everything on film.”

Wherever I looked, staffers were handling, preserving and curating film. A young woman shipping a print of the 1950 musical “Annie Get Your Gun” to a film festival. A laboratory specialist repairing the tears in a fragile negative of “Seed,” a 1931 melodrama that featured a very young Bette Davis.

And, in a darkened room, two technicians waiting to show me a scanned copy of about 135 seconds of “The Callahans and the Murphys.” But where did it come from?

The catalog information indicates only that it was a single-item donation from an Anthony Tarsia of Fairfax, Virginia, on Dec. 4, 2001.

Tarsia, it turned out, was helping to declutter his mother’s home in Rockland County, New York, when he found boxes of film reels that transported him back to his childhood, when his late father would project old movies onto a bedsheet curtain. Many came from a family friend who delivered movie reels to theaters and TV studios.

Rather than head to a landfill, Tarsia contacted the Library of Congress. Soon he was unloading his father’s cache at the institution’s door in Washington.

“And that’s the last I ever heard of them,” Tarsia said recently.

The one true find in the Tarsia donation was the 16-millimeter “Callahans” fragment that at some point had been copied from the 35-millimeter original. Many silent films survive only on inferior 16-millimeter prints made by distributors or buffs or companies that catered to schools, prisons and other nontheatrical clients.

The short treasure was cataloged, processed, placed in a new case and eventually shipped to the Culpeper bunker, where it sat, undisturbed for years, until I inquired. Then, recently, came another inquiry, this one from the Irish Film Institute, in Dublin. An archivist there had discovered a different clip from “The Callahans and the Murphys” in its collection, one that long ago had misleadingly been renamed “An Irish Picnic.”

“It had been sitting there, essentially, for 20 years, without anyone realizing what it was,” said Kasandra O’Connell, who oversees the institute’s film archive. “Huge excitement, as you can imagine.”

This grainy clip, nearly three minutes long, includes a few of the controversial scenes. Mrs. Callahan and Mrs. Murphy go to a St. Patrick’s Day picnic, drink huge mugs of beer and proceed to get pickled. (“This stuff makes me see double and feel single!” says Mrs. Murphy.) A raucous dance leads to a, well, a donnybrook.

The Library of Congress and the Irish Film Institute made plans to share their clips online for St. Patrick’s Day, by which time I hoped to be back above ground. But first: my private screening of the Library of Congress fragment in this memory shelter embedded in a mountain.

A technician tapped on a keyboard, and an uncertain 2024 blurred into the distant 1927.

It seems that the Callahans have run out of sugar. A chubby son is dispatched across the alley to borrow from Mrs. Murphy, who gladly fills a cup to overflowing. But the boy eats most of the sugar on his way home. Handed the nearly empty cup, Mrs. Callahan accuses Mrs. Murphy of being stingy.

Arguments ensue. Misunderstandings abound. The way of the world.

As black-and-white ghosts cavorted across the screen, I could only wonder what my mother from Galway — who never acted like that! — might have said about this silent comedy, Irish stereotypes and a son lost again down another rabbit hole.

This article originally appeared in The New York Times.