Art-loving Americans, now just about unshockable, ought to pause a moment Wednesday to celebrate the day -- 75 years ago -- when, midst trumpet blasts and hoo-ha, "the modern" hit New York.

In the slow, unfolding story of the history of taste, few instants of significance can be located so precisely. The date was Feb. 17, 1913. The place was the 69th Infantry Regiment's turreted new armory between 25th and 26th streets on the East Side of Manhattan. The time was early evening. Bayne's regimental brass band snapped smartly to attention. The uniformed conductor nodded to his trumpeters. The moment had arrived. A fanfare split the air.

Four thousand New Yorkers were about to be confronted with ... well, with what they were not sure. A complicated hoax? A vast and tasteless joke? A cubistic-futuristic vision of the future, or an evil foreign plot designed to subvert Christian morals? The occasion was the opening of the Armory Show, the Association of American Painters and Sculptors' International Exhibition of Modern Art. It all seems a little quaint now, but the sense of scandal was electric. The papers were delighted. Free love and white slavers, alienists and anarchists, and now ... Modern Art.

As the brassy music faded, painter Arthur B. Davies, the association's president, introduced John Quinn, collector and attorney and guiding spirit of the enterprise. Quinn knew how to make the headlines. "This exhibition," he prophesied, "will be epoch-making in the history of American art. Tonight will be the red-letter day in the history not only of American but of all modern art." He may have been right.

The Armory Show has become the stuff of legend. It tends to be remembered as a focused exhibition aimed at Picasso and Matisse, at Brancusi and Duchamp, or as New York's first exposure to strange new art from Europe, or as a daring, artist-organized attack on convention. The truth is more complex.

Focused it was not. It was enormous and chaotic and nearly indigestible. No one knows exactly how many works were shown, but the catalogue suggests there were nearly 1,300, in 18 rooms. Not all of them were new (the show included pictures by Goya, Delacroix and Ingres), and the Europeans represented were outnumbered by Americans more than two to one.

Arthur B. Davies, Walt Kuhn, Elmer MacRae, Jerome Myers and Henry Fitch Taylor, the New York painters most responsible for assembling the show, were hardly revolutionists. Their scenes of Lower East Side urban life, sea gulls and madonnas, nymphs dancing in the woods and little girls in sweet white frocks no longer shock at all. All five are represented in "The New Spirit: Artist-Organizers of the Armory Show," a modest, in-house show at the Hirshhorn Museum and Sculpture Garden.

Nor was the Armory show all that unprecedented. The impressionists of France had begun arranging shows of their own art in the 1870s. The enormous exhibitions of the Salon des Inde'pendants, and, after 1903, the even more audacious Salons d'automne, had long been standard features of the Parisian scene. Similar exhibits had also been arranged in London and Cologne.

Even for Manhattan, the Armory exhibition was not entirely a first. Picasso and Matisse, and Rousseau and Ce'zanne, had already been displayed by Alfred Stieglitz at 291 Fifth Ave. But Stieglitz was in many ways a bit of an elitist; if his audiences were tiny, that was fine by him.

The Armory Show, in contrast, drew vast and eager crowds. "You haven't any idea how this confounded thing has developed," organizer Kuhn wrote his friend Rudolph Dirks (creator of the comic strip the "Katzenjammer Kids"). "Every afternoon Lexington Avenue and the side streets are jammed with private automobiles, old-fashioned horse-drawn equipages, taxi cabs and what not. To give you an idea of what a hit the show has made, I might merely state that the receipts for admission and catalogues last Sunday amounted to $2,000 ... That's going some, isn't it?"

Attendance sometimes reached 10,000 a day. Milton W. Brown, in his book on the exhibit, writes that "Mrs. Astor came every morning after breakfast ... Frank Crowninshield, a devoted advocate of the new art, was in frequent attendance ... Enrico Caruso, the great singing star of the Metropolitan Opera, turned up one Saturday afternoon and thrilled the crowds by doing caricatures of the paintings on Armory Show postcards and distributing them as souvenirs. The scion of the Morgan family was outraged that he had to pay twenty-five cents to see such trash ... Former President Teddy Roosevelt picked March 4, appropriately enough, to visit the Armory Show while President-elect Woodrow Wilson was taking the oath of office."

"A Layman's Account of an Art Exhibition," Roosevelt's report of the pictures he had seen, was published soon thereafter. "It is vitally necessary to move forward and to shake off the dead hand of the reactionaries," wrote TR. "And yet we have to face the fact that there is apt to be a lunatic fringe among the votaries of any forward movement. In this recent exhibition the lunatic fringe was fully in evidence, especially in the rooms devoted to the Cubists and the Futurists, or Near-Impressionists."

The crowds who filled the galleries were not the first Americans to discover the strange new art of Europe. Gertrude and Leo Stein, Stieglitz and Quinn, the Cone sisters of Baltimore and other connoisseurs had been buying it for years. But hardly anyone had noticed. Now everyone was buzzing. The exhibition, observed Myers, "had unlocked the door to foreign art and thrown the key away." What made the Armory show a watershed was the way that it exploded in the press and in the public mind.

The papers had a field day. A diatribe in the Review opened by condemning the "degenerates of art," and went on from there: "The propaganda of the Cubists, the Futurists and Post-Impressionist painters is not only a menace to art, but a grave danger to public morals." A Mrs. Carey Sheffield, quoted in the Journal, clothed her indignation in wilder invective -- "disgorgings of a curdled imagination," "disorders of a feverish brain," "degrading, degenerate and an evil influence," "bilious and lurid canvases of decomposed flesh." "If the bomb thrower is imprisoned, the defamer and lunatic is confined ... why then," asked Art and Progress, "do we so blithely tolerate these same crimes in art?"

While many writers spluttered, others chose to laugh. In Chicago, Harriet Monroe (who was more responsive to modern poetry than to modern painting) told the readers of the Tribune that "if these groups of theorists have any other significance than to increase the gayety of nations, your correspondent {is} unaware of it."

The gibes came thick and fast. Some were told in verse. This one, called "A Post Impression," was published in the Sun.

Awful lack of technique

Awful lot of paint

Makes a Cubist picture

Look like what it ain't.

A number of publications reported that one of the works exhibited was created by a donkey that swished the paint on with his tail. (This story will not die: It was told of the impressionists; Khrushchev used it too, and, in its a-chimp-could-paint-a-Pollock mode, it is with us still.)

Picasso's cubist pictures received a lot of stick, as did Constantin Brancusi's plaster, "Mlle. Pogany," which one wag described as "a hardboiled egg balanced on a cube of sugar."

But of all the works on view, the one that was most noticed, and happily attacked, was "Nude Descending a Staircase" (1912) by Marcel Duchamp.

That Duchamp had abstracted the temple of the body, femininity itself, was thought particularly outrageous. "What contributed to the interest provoked by that canvas," the artist observed later, "was its title. One just doesn't do a nude woman coming down the stairs, that's ridiculous. It doesn't seem ridiculous now, because it's been talked about so much, but when it was new it seemed scandalous. A nude should be respected."

And, in painting, should stay still. But Duchamp had decided to put his nude in motion. "There was something funny there, but it wasn't at all funny when I did it ... I wanted to create a static image of movement ... When you wanted to paint an airplane in flight, you didn't paint a still life."

Jokesters loved the picture. It was variously described as "a lot of disused golf clubs," a "dynamited suit of Japanese armor," and, most famously, as "an explosion in a shingle factory." A cartoon version of the painting, published in the Evening Sun, was called "The Rube Descending a Staircase (Rush Hour at the Subway)."

Duchamp was delighted. He always liked a joke. "The funniest thing is that for at least 30 or 40 years the painting was known, but I wasn't. Nobody knew my name ... Everyone had seen the painting, or reproductions, without knowing who had painted it ... {I lived} without being bothered by the painting's popularity, hiding behind it, obscured. I had been completely squashed by the 'Nude.' "

What pleased him most of all was that the painting sold.

It went for $324. The painting (later acquired by Walter Arensberg and now in the collection of the Philadelphia Museum of Art) was purchased, sight unseen, by one F.C. Torrey, a San Francisco dealer. Torrey's telegram -- "I WILL BUY DUCHAMP NUDE WOMAN DESCENDING STAIRWAY PLEASE RESERVE" -- is among the documents displayed in the Hirshhorn's little show.

Other works were sold as well, 174 in all, 123 by foreigners, 51 by Americans. The total take amounted to $44,148.

Quinn bought the most, works by Redon, Signac, Segonzac and half a dozen others. They cost him $5,808.75. The second largest buyer -- and perhaps the most adventurous -- was Arthur Jerome Eddy, an attorney from Chicago, who paid $4,888.50 or 25 prints and paintings, among them two Duchamps, a Villon and a Picabia. Stieglitz paid $135 for five Archipenko drawings, and an additional $500 for the exhibition's sole Kandinsky. Even Henry Frick of the Frick Collection came to buy a picture, an $87.50 flower piece by Walter Pach. Many young collectors who would later become famous -- among them Dr. Albert Barnes of the Barnes Collection, Arensberg and A.E. Gallatin -- also purchased from the show.

The most important sale, and the highest price, was the $6,700 paid for Paul Ce'zanne's "Colline des Pauvres" by the Metropolitan Museum of Art.

That landscape was the first Ce'zanne to enter the collection of an American museum.

Well, kudos to the Met. But still one can't help thinking of all the other major things that remained unsold.

You could have bought, for instance, plasters by Brancusi at $270 each. Oils by Georges Braque were priced at $202.50. Ce'zanne's "Bathers" was available for $6,500, and paintings by Gauguin cost $4,050 each. There were 18 van Goghs in the show. His painting of his wooden shoes was priced at $2,600. The two unsold Le'gers on view cost $216 each. Matisse was represented by more than 20 pictures. His "Nasturtiums and the Dance, II" was available for $1,080, and his magnificent "Red Studio," now in the collection of the Museum of Modern Art, was listed for $4,050. A sheet of his nude studies was the only Matisse sold. It cost $67.50.

Assembling the Armory Show must have been great fun. The organizing artists went at it with a will.

The idea was set in the summer of 1912, when Arthur Davies saw a catalogue of an international exhibition then on view in Cologne. The German show was vast, and it did its best to place the newest art of Europe in historical perspective. "I wish we could have a show like this," Davis wrote Walt Kuhn.

"In a flash I was decided," Kuhn would recall later. "I wired him to secure steamer reservations for me; there was just time to catch the boat ... His parting words at the dock were, 'Go ahead, you can do it.' "

Kuhn arrived Sept. 30, the last day of the exhibit. One gathers he was stunned. The show included 125 works by van Gogh, 26 Ce'zannes, 25 Gauguins, and 16 pictures by Picasso. Kuhn began arranging loans. He then visited The Hague, Munich and Berlin, dealing with the dealers there, urging them to loan.

From France, he wired Davies, saying he needed help. Davies booked his passage, and arrived Nov. 6. What the visiting Americans -- and their friend Walter Pach, who guided them through Paris -- assembled in the next 10 days would fill a small museum of early modern.

They visited the three Duchamp brothers, Brancusi and Matisse, and such expatriate Americans as Morgan Russell, Elie Nadelman and Patrick Henry Bruce, all of whom agreed to send works to the show. Through the Steins they got in contact with Matisse and the Fauves. Dealer Amrboise Vollard agreed to send New York a group of Ce'zannes and Gauguins. Durand-Ruel came though with the impressionists Monet and Renoir. Henri Kahnweiler agreed to lend Braques and Picassos. The largest loan of all came from dealer Emile Druet, who came up with more than 100 works, including post-impressionist canvases by Seurat and van Gogh, Ce'zanne, Signac, Toulouse-Lautrec, Rouault and Matisse.

When one remembers what they borrowed, it comes as something of a shock to walk into the Hirshhorn and see the sort of pictures, mild, unadventurous, that they produced themselves.

Davies' moody paintings still seem slightly silly. Symbolist in spirit, they make the viewer think of lots of Isadora Duncans dancing through the woods. Kuhn's pictures at the time were even more conservative, though they had a certain toughness he maintained throughout his life. The French paintings he collected must have had some impact. His "The Tragic Comedians" (1916) hints a bit at cubism, and at the usually unhappy acrobats of Picasso. It is the strongest work on view.

Elmer Livingston MacRae, the association's treasurer, kept meticulous records. After his death in 1955, his papers were discovered in an orange crate in a barn behind his house at Cos Cob, Conn. Joseph Hirshhorn bought them. He also bought the art displayed in the current show.

Jerome Myers' street scenes, Henry Taylor's cubist works and the MacRae's oddly varied canvases and carvings are nothing to write home about. Seventy-five years ago these artists were regarded as adventurous progressives determined to escape what then seemed the restrictions of academic art. But nothing they made themselves had an influence so great as the giant exhibition they helped arrange.

The Hirshhorn's exhibition (which closes March 13) was picked by Judith Zilczer. It has an oddly ghostly air.

Zilczer calls attention to a 1913 letter written to MacRae by Flora McDonald Thompson asking "whether, in your opinion, it would be possible to bring the {Armory Show} to Washington?"

The exhibition never reached this city, except by implication. Something of its spirit, its flash and its ambition, is apparent at the Phillips, in the National Gallery's East Building, in almost every one of this city's commercial galleries and on each floor of the Hirshhorn.

The Armory Show evoked bafflement and fury, curiosity and wonder. Like one of Cupid's arrows, it sparked our rocky love affair with avant-garde art.