IT is hard to take seriously a group of grown men and women who submit a store-bought urinal to an art show, declaim meaningless sounds as poetry, stage mock trials of novelists they dislike, wear a string with two empty tin cans as a bra, provide an ax for dissatisfied art connoisseurs, call their movement Dada, and then proclaim proudly, "Dada means nothing."

Yet these artists of shock from World War I and the 1920s have now been taken seriously enough for the National Gallery of Art to mount a striking and didactic exhibition of their work — the first time a major American museum has devoted a show solely to Dada. And Leah Dickerman of the National Gallery, who co-curated the show, has no hesitation in making sense and significance out of the maddening antics of these artists. "Dada," she says, "has arguably had the largest influence of all avant-garde movements on contemporary art."

An expanded version of the exhibition attracted almost 400,000 visitors last fall at the Centre Pompidou in Paris, the home base of the other co-curator, Laurent Le Bon. Although the National Gallery show, which closes May 14, is smaller, it is still extensive, with 450 works from 50 artists, including Jean (Hans) Arp, Otto Dix, Marcel Duchamp, Max Ernst, George Grosz, Francis Picabia, Man Ray and Hans Richter. After Washington, the exhibition goes on to the Museum of Modern Art in New York from June 18 to Sept. 11.

"The idea of Dada as nonsense is commonplace," Dickerman says, "but this exhibition helps us to see it as a very calculated nonsense." The art came out of a revulsion against the horrors of World War I. Many of the Dadaists were draft dodgers, discharged soldiers with wounds, or rejects disqualified from military service for physical or mental problems. All abhorred the war.

Now, after a century of sophisticated and wanton destruction on an unprecedented scale, the horrors of World War I may seem somewhat diminished. But the shock and horror were immense then. Young people had moved into the 20th century persuaded that the inventions of the industrialized age would make modern life more comfortable and exciting. Instead the new inventions — planes, submarines, poison gas, semiautomatic rifles — were used to kill more efficiently and more horribly. Almost 10 million soldiers were killed. More than 20 million were wounded. Many came home without legs or arms, many disfigured or in shell shock.

The horror spawned a crisis of confidence. The French poet Paul Valéry said, "The illusion of a European culture has been lost, and knowledge has been proved impotent to save anything."

Dada began during the war in Zurich, the large German-speaking city in neutral Switzerland. Hugo Ball, a German, started the movement with antiwar performances at the Cabaret Voltaire. He and another German exile, Richard Huelsenbeck, came upon the name by searching a French-German dictionary. They liked the sound of the word "Dada," which means "hobbyhorse" in French. Their group was soon joined by other expatriates such as Arp, a painter from Alsace; Richter, a German artist and filmmaker; and Tristan Tzara, a poet from Romania.

As if he were turning his back on European culture, Ball, dressed in a cardboard costume, would recite what he called sound poetry and poems without words. "Hollaka hollala, anlogo bung, blago bung, blago bung, bosso fataka," he would intone. In another variation, Tzara and two other poets would recite a "simultaneous poem" together, one speaking in German, another in English and the third in French. The jumble would not sound much different from Ball's blago bung, blago bung. The exhibition features recordings of these kinds of performances.

In art, Arp broke with the norm by creating colorfully painted and abstract wood reliefs, while Richter painted what he called "visionary portraits" — painting his subjects while he put himself into a trance-like state at twilight and could barely see them.

The name Dada might have died in Zurich if Tzara had not taken it upon himself to serve as polemicist for the movement, preparing a manifesto and newsletters that he sent to artists in Europe and the U.S. Dada, anchored in Zurich, soon developed in Berlin, Hanover, Cologne, Paris and New York.

Historic rejections

THE best-known Dadaist at the time was probably Duchamp, the French artist who spent the war years in New York. The United States remained neutral during World War I until 1917. Duchamp had already attracted attention with his painting "Nude Descending a Staircase, No. 2." Painted in Cubist style, it creates the illusion of a mechanical figure in motion.

But the entry committee of the Salon des Indépendants in Paris refused to hang the painting when he submitted it in March 1912. Committee members felt the painting showed too much motion for a Cubist painting. A year later, however, the painting was the sensation of the New York Armory Show that introduced the latest European trends in Modern art to many Americans.

Duchamp precipitated another historic rejection in 1917. He bought a porcelain urinal in a store, turned it upside down, signed it "R.Mutt," added the year, titled the piece "Fountain," paid a $6 entry fee, and submitted the work to an American exhibition. The shocked sponsors rejected the entry. But it became an icon of Modern art.

The original "Fountain" disappeared but became renowned through a photograph by Alfred Stieglitz. Duchamp pleased his admirers in 1964 by buying several more porcelain urinals and marking them "R.Mutt 1917." One is displayed in the National Gallery show. (Another, at Centre Pompidou in Paris, was chipped in January when a man attacked it with a hammer, Associated Press reported. A Paris court sentenced the man after rejecting his claim that the action was performance art.)

In 1919, while in Paris, Duchamp took a reproduction of Leonardo da Vinci's Mona Lisa and penciled on a mustache and beard. Then he penciled the title, "L.H.O.O.Q." When these letters are sounded out slowly in French, they seem to say, "She has a hot bottom."

Duchamp's shocking works lend some credence to the Dada contention that its followers reject art. But Dickerman does not agree. "Despite their anti-art rhetoric," she insists, "Dada is hardly a wholesale disavowal of art but a revolution in its rules."

Duchamp, for example, did not shock potential customers when he mounted a bicycle wheel on a stool in 1913, turning the two ready-made pieces into an unusual and pleasant sculpture. In true Dada fashion, with both the urinal and the bicycle wheel, Duchamp was trying to prove that art can be wrought from many kinds of things and is not restricted to the materials used in art academies.

In the past, museums have often tacked Dada on to Surrealism shows as a precursor. It was tempting to do so since André Breton, a Dadaist writer, later became the guru of Surrealism in Paris, and Max Ernst, a Dadaist painter, made his mark a few years later as a Surrealist painter. Ernst's "Submerged by the Waters," painted in 1919 when he was a member of the Dada group in Cologne, is a good example of Dada molding into Surrealism. There is an eerie, dream-like atmosphere as a swimmer stands upside down in a pool, an armless statue guards the scene, and a moon shows the face of a clock. Ernst was so caught up in the movement that he sometimes signed his work "Dada Ernst" and created a poster crying out "DADA siegt! (DADA Triumphs!)" for an exhibition.

The National Gallery show demonstrates that Dada artists also followed other paths than Surrealism. The surest evidence comes in the display of works of the Dada group in Berlin just after the war. There are biting, bitter paintings and drawings by artists who would become great social critics of life in Germany between the world wars. The most dramatic examples are the works of George Grosz and Otto Dix.

In a 1920 work of watercolor, pencil and photomontage called "The Convict," Grosz depicts a broken soldier and revolutionary with a mechanical heart frustrated in a jail cell. The figure is supposed to be Grosz's fellow German Dadaist John Heartfield, but the angry face resembles Grosz far more. In a 1921 painting, "Gray Day," a smug industrialist walks past a crippled veteran without even glancing at him.

Dix paints with even more anger. His 1920 "Skat Players" shows three war veterans playing cards. Two are legless. Two are armless. All have disfigured faces. One holds cards with his mouth, one with his foot. One wears a medal. Dix, who received an Iron Cross for his valor, was wounded several times during the war.

What ties the disparate works of artists like Duchamp, Ernst, Grosz and Dix together is a community of iconoclastic or Dada feeling. This feeling is amply illustrated in the National Gallery show by dozens of posters, books, magazines, newsletters, manifestos, photographs and movies produced by Dada.