He isn't mentioned in its title, but "Els Quatre Gats: Art in the Barcelona Around 1900," now at the Hirshhorn Museum and Sculpture Garden, is a show about Picasso. It tells us less about the master's innovative paintings than it does about his youth and aprenticeship.

"Els quatre gats," in Catalan, means both "the four cats" and "the in group". Els Quatre Gats also was the name of the Barcelona tavern where Picasso, not yet 20, played, learned and hung out.

Perhaps some sociable young scholar should undertake a study of the role of bars in art: How did the dance halls of Montmarte change Toulouse-Lautrec? How much of its seediness did the Cedar Bar give to postwar New York painting? Washington, alas, would not deserve a mention. The painters of this city tend to drink at home.

In Barcelona they hung out. Els Quatre Gats which advertised itself as "an inn for the disillusioned," was more than a mere tavern. Pictures lined the walls, shadow-puppet plays were offered in the evening, and in one session titled "Edison: A Great Man," a new phonograph was played were in 1899. Part gallery, part theater, Els Quatre Gats above all was a mecca for those painters, poets and musicians alled to modernismo , the Catalan avant-garde.

When its pseudo-Gothic portals opened to the public in 1897, Picasso was 15.

The exhibit at the Hirshhorn tells us much about him. He was, as a young man, entertaining, useful. He designed the cafe's menu, made its hanging metal sign, he portrayed the cafe's founders and caricatured their friends.

Also he made doodles. There is one drawing here - it shows flamenco singers, squiggles and a pair of broadhipped nudes - that he signed a dozen times, 10 times at "Picasso," once as "Yo Picasso," and once a "Yo el Rey" ("I the King"). He must have sometimes seemd less a mighty painter than a gifted, cocky kid.

Daily at Els Quatre Gats he listened and looked. It is clear that he learned much there from his older, traveled colleagues. We see it in their pictures. Their affection for the circus, their compassion for the poor, their pleasure in experiment and in la vie boheme , were absorbed ther by Picasso, and remained with him for life.

The artists at Els Quatre Gats - even young Picasso, who came from Malaga - spoke Catalan, not Spannish. They were nationalists all. But their hearts were set on Paris. Their academic portraits, their art nouveau posters, their Degas imitations, frequently appear less Cataland then French.

The cafe had four founders: the painters Ramon Casas, Santiago Rusinol and Miguel Utrillo, and Pere Romeu, who became the bar's proprietor. The name that they selected referred both to their foursome and to Le Chat Noir, to famous French cafe, for France and moved them all. Cases and Rusinol were particularly familiar with its art world and its night life, for they went each year to Paris, where they kept a flat above the wellknown dance hall, Moulin de La Galette.

It is easy to imagine the stories they brought home. They had seen the latest paintings, heard the latest songs. They knew Toulouse-Lautrec and Yvette Gilbert, and also Erik Satie, who often had played piano at Le Chat Noir, and whose portrait, by Casas is included in the show at Els Quatre Gats. Later in that year, Picasso and his artist friend Carles Casagemas left Spain for the first time to see Paris for themselves.

They must have had a wild time. There is a small Picasso here that shows the painter and his friends, apparently all stoned, holding hands and dancing with two women and two dogs just outside the gate of the 1900 Exposition Universelle.

Picasso was a ladies' man - he could take them, he could leave them. Casagemas was less flighty. He fell in love in Paris, unhappily so, with one of those two women, and though he returned home to Els Quatre Gats, his depression deepened. In 1901, he returned to Paris, where he killed himself.

Stories of that sort - part gossip, part art history - energize this show.

On their fateful trip to Paris, Picasso and Casagemas stayed in the apartment of the Barcelona painter Isidro Nonell. That fact seems to be an inconsequential footnote until one discovers an oil painting by Nonell called "Misery: Tow Gypsies." Its mood, and its colors, are heavy, sad and dark. All of us have seen the now world-famous paintings of youngs of young Picasso's Blue Period. But until one looks at "Misery: Two Gypies," one does not appreciate how much the master learned from his older friend, Nonell.

There is a small picasso portrait here of Eveli Torent, the Barcelona painter who escaped wrack and ruin. Torent later made his living painting formal portraits of such well-known figures as President Woodrow Wilson and England's King George V.

Nearby on the wall is a little portrait by Miguel Utrillo, one of the four founders, of the Paris painter Suzanne Valadon. The drawing is inscribed "In memory of the seven-year war." The catalogue tells why.

Suzanne Valadon (c. 1865-1938) began her career in the circus. She then became a model, posing for such painters as Renoir, Toulouse-Lautrec and Puvis de Chavannes. No less a master than Degas taught her how to draw. In 1883, in Paris, Miguel Utrillo met her at the cafe Le Chat Noir. The two painters became friends. In December of that year, Suzanne bore a son whom she named Maurice.In 1891 - when "the seven-year war" ended - Miguel signed an official act of paternal recognition. When the son became a painter, too, it was as Maurice Utrillo, not Maurice Valadon, that he gained his fame.

Edison and Degas, Wilson and Utrillo - wonderful the gossip that runs through this show.

It is only at its end, in Picasso's splendid painting of the "Crouching Woman," that there are glimpses of the marvels yet to come.

The Blue Period Picasso was made in 1902, when the Spanish economy was reeling from the loss of the Spanish-American War, and the government in Madrid was becoming increasingly repressive. Picasso moved to Paris, as did many of his friends. Things in Barcelona would never be the same. In July of 1903, six years after it opened, Els Quatre Gats closed its doors.

"Els Quatre Gats: Art in Barcelona Around 1900" was organized at Princeton UNiversity by Marilyn McCully, a member of her students there helped with the research. The byways of art history are often quite as interesting as the major highways. McCully and her students offer a moving, though didactic, show. It closes at the Nirshhorn on June 26.