The paper cutouts of Henri Matisse at the National Gallery of Art are works of healing glory. The bedridden old master made them in dark days.

His surgeons had nearly killed him. His France had been invaded, his daughter tortured, his wife imprisoned. Matisse was in his 70s when, in 1941, he put down the brush and took up his sharp scissors. He had, he said, prepared for death. But unlike Goya, or Rothko, he did not paint its picture.

As dying stars burst into light, so did the aged Matisse. Matisse took his stiff sheets of white hand-pained paper, cut color "signs" and glued them to a backround in precisely the right place.

In them is distilled the learning of a lifetime. Classical, prophetic, they rank, as this show demonstrates, with the most distinguished masterworks of 20th-century art.

They will be on view six weeks, from Saturday through Oct. 23. Because their true significance has not before been gauged, this, the first full survey of the cutouts of Matisse, is the most important modern show yet offered by the National Gallery of Art.

Beginning with small studies from the 1930s, and ending with his huge designs for the stained-glass windows of the Chapel of the Rosary of the Dominicans at Vence, the exhibition surveys the master's exploration of the medium to which he devoted the last years of his life.

There are 55 works on view, among them "La Negresse," a set of the "Blue Nudes," the "Large Composition With Masks," and "The Swimming Pool," on loan from the Museum of Modern Art. The cutouts range in size from studies that are post-card small to room-size environments. The exhibit is not huge, but in beauty these collages take the breath away.

Most collages jar, juxtaposing images that are strident and combatant. Much modern art disorients, trying the viewer's spirit with its challenges and shocks.The cutouts of Matisse give peace. He knew his art could heal.

"On several occasions, believing his paintings capable of emanating their own light, he endeavored to perk up sick friends by surrounding their beds with his canvases," notes the 304-page monograph accompanying this show.

"I dream," he wrote in 1903, when he was still a Fauve, a "Wild Beast," "of an art of balance, of purity and serenity, an art which could be . . . something like a good armchair which provides relaxation from physical fatigure."

He achieved that through his colors, harmonies and rhythms, and his mastery of "signs."

"Color tones you up," he said, but his colors, unlike those employed by the hard-edge painters of the '60s, are never merely bands or stripes. They serve pictorial ends.

He called his villa near Vence "The Dream." He dreamed, and he here shows us, the lovliest of things - nymphs in pools and gardens, the tales of Scheherazade, the bacchanal, the winepress, the sky, the Christ, the sea.

Though color field painting, the miunimalist esthelic, the '60s art of Motherwell, Youngerman and Kelly and much more were predicted by his cutouts, the "radical" Matisse was a traditionalist as well.

Matisse (1869-1954), was at first a 19th-century painter. A law student, a bourgeois, he was already in his 20s when he turned to art. He drew from plaster casts, made copies in the Louvre and trained in the academies. Though he later would perfect his "genius for omission," his work always celebrated the goddesses and myths of Mediterranean art.

"The importance of an artist," he believed, "is measured by the number of new signs he had introduced in to the language of art." He knew that "one must study an object a long time to know what its sign is." The signs he cut so beautifully - those flat forms of one color in which volumes, weights and swellings are not seen, but implied - still startle with their radical simplicity, economy, and newness. But the iconic things they conjure - pomegranates and ponies, acrobats and dancers, stars, seabirds, and heroes - are ancient.

There is, in this exhibit, a sense of soaring in time as well as space. The bedridden Matisse, in his studio in Nice, would surround himself with doves. "Doves, their spheres, their curves, glide in one as in a large interior space," he wrote. "When I am doing the cutouts, you cannot imagine to what degree the sensation of flight which comes to me helps me to adjust my hand as it guides the path of my scissors. It's hard to explain . . ."

Though in the '20s and '30s Matisse had used cut paper as an aide to composition while working up his oils, it was not until the war, and his "terrible" operation (for a blocked in testines followed by debilitating infections) that he realized the full potential of the medium. The technique, he explained, "is not a starting point, but a culmination."

"The cutout paper allows me to draw in color. It is a simplification. Instead of drawing an outline and filling in the color - in which case one modifies the other - I am drawing directly in color." Matisse had not abandoned drawing, painting, sculpting. Instead he'd learned at last to do all these things at once.

No longer was Matisse confined to the scale of the easel. Now his signs could capture whole walls or whole rooms. Of the cutouts at the Gallery, some are book-size, some enormous. "La Negresse," his jungle goddess, is tall as a giant. "La Piscine" ("The Swimming Pool"), his joyous flowing frieze of water sprites and starfish, is 54 feet long.

The cutouts of Matisse, especially the ones he made for the book that he called "Jazz," have frequently been reproduced on small, flat-colored posters. One great virtue of this show is that it reminds us how much these handmade pictures lose from reproduction.

"These works," the artist warned us, "cannot be reproduced in multiple copies because, as with a tracing, they would lose the sensibility that my hand brought to them."

"Here we see his process (the thumbtacks, too), his trials and adjustments. Along their curving edges the glued paper casts shadows. The thigh of "Blue Nude" is not just one piece of paper, but three or six or 10.

And no machine, no printing press, could reproduce the rightness, or the brushed striations, of his perfect colors.

Two yellows dancing side by side, change, as the eye moves, from two tones into one. "The Large Composition With Masks," a garden of bright reds, blues, oranges and yellows, is suddenly perfected by four small spots of brown.It was Van Gogh who said, in 1888, that "the painter of the future will be a colorist such as never yet existed." He might have been predicting the late art of Matisse.

But no sooner does one start to feel that color is the key, that one discovers, as in the late "Blue Nudes," that Matisse could somehow draw comparable beauty from shades of blue alone.

Five of the best cutouts, shown among them "La Negresse," were purchased a few years ago by the National Gallery, Director Carter Brown, who bought them (with funds provided by the late Ailsa Mellon Bruce) had his priorities in order.

The show, as usual is well-installed. The scheme is chronological. The cutouts have been placed so that their colors are not in combat, and so that each work breathes.

The exhibition was organized by Jack Cowart of the St. Louis Art Museum and John Hallmark Neff of the Detroit Institute of Arts. The firstrate monograph they wrote illustrates more than 200 cutouts, not just the 55 on view.

Some masters fade with age. Matisse, like Beethoven and Milton, Titian and Le Corbusier, soared highest at the end.