Events on stage come through once. You're told, perhaps, about Ethel Merman shattering lorgnettes in the balcony with a leftover note from "Girl Crazy" or about Tallulah Bankhead with a feather duster in "The Skin of Our Teeth" or Victor Moore scurrying around in a cutaway in "Of Thee I Sing." Those performances are gone, stage ghosts fled, and without a tale by which we can retrieve them. We love our movies; they can visit us nights and on weekends. But when a beloved performance passes through on the stage all you can do is get it once and then pass it along, like a smoke signal, to other generations.

On 43rd Street, in New York, there's an old theater newly renovated called the New Apollo. It is after 8 and the curtain is up on a lit stage for Lanford Wilson's "Fifth of July." Suddenly there is this blazing apparatus on stage, a young woman with mad-frizzed orange hair -- shooting in two definite directions, stage left and stage right, from the part in the middle of her level head -- a sloped rubbery nose, unfathomed depths of dimples, cheeks of puckered potatoes, an overbite that ledges over a chin that is either no chin or too much chin, but at any rate juts down like a dropped lemon. It's Swoozie Kurtz who is some of all those independent pieces of kinetic sculpture, and the sum of it all is beauty -- real beauty -- and a performance that you might want to see and save for your old age.

She stands on the stage and owns a piece of it, nearly dominating a play she was meant to support. The rest of the ensemble -- including Richard Thomas and Amy Wright -- is complex and strong, but in Kurtzhs mad, cokewired, scythe-edged heiress Gwen there is a merger of part and actress that lives with you.

It's backstage at the New Apollo, among the pulleys and sandbags of the theater and the lights and dangling cords and sound equipment. Amy Wright, an actress in her 20s who plays a 14-year-old Tally family member named Shirley, is running back and forth, in and out of sets, shooting around behind the curtains and giggling. Swoozie is on stage. It's almost the 300th performance of "Fifth of July," and yet the stage crew is standing, watching her work, watching her hold the audience with her description of her father's stroke in a way that makes the audience laugh and feel the shadow of the stroke at once: "His face is all paralyzed, but it's struck in this real weird, kind of comic position," she says, and she does it, and the audience laughs, hard, hard until it hurts, and then holds its breath.

Swoozie Kurtz is one of those actresses who has, for the last 10 years, been called one of the promising young stars of the American theater. Her clip book is almost impossible to stumble through without a sense of near voyeurism, so effusive and almost slathering is the total critical effect. Over and over in the last few years she has delivered in roles written by notable American playwrights, but it's one of the cultural mistakes of our era that the best young actors and actresses who work on stage -- playing to 5,000 to 10,000 or 15,000 people a week -- remain almost unknown. For power, they go to Hollywood, do our kind of national repertory theater (which is sitcoms) and return to the stage -- as Hal Linden after "Barney Miller" or Judd Hirsch after "Taxi" -- a draw. Swoozie Kurtz hasn't yet paid her dues in the mass market, but whenever America needs a new Lucy, here's one who could take pies weeknights at 8 and do Moliere on the weekends.

It's not that she hasn't made her haphazard stabs at plugging herself into national networks --she was part of the troupe of actors (including David Letterman and Dick Shawn) who tried to hold up the immense weight of the disastrous Mary Tyler Moore variety show two seasons ago. "This could be fabulous for me," she told a reporter as she was packing for Los Angeles in 1978 to prepare for the mass numbers and hard laughs in Studio City, "or it could be a disaster."

It was the disaster but it didn't make a dent. She came west with a powerful line of theater credits and came home for more. She won Tony and Obie and Drama Desk nominations and worked in "Tartuffe" with John Wood, Wendy Wasserstein's "Uncommon Women" and Christopher Durang's respected flop, "A History of the American Film," in which she played parts from Susan Alexander Kane in "Citizen Kane" to Dr. Strangelove in "Dr. Strangelove." She worked in plays by Hugh Leonard, A. V. Gurney Jr. and Tom Stoppard. She worked summers at the O'Neill Rep and winters on Broadway, and Frank Rich called her "splendid" and Jack Kroll called her one of the "best young American actresses" and Clive Barnes called her "brilliant," and nobody knew who she was. She could convulse audiences and make them cry, but unless she did a television show in which she played a lady bus driver or a hot-to-trot-high-school-teacher-with-a-heart-of-platinum, nobody would know who she was.

"I don't know where it comes from" she says. "I think you're either just born with comic timing or not, like straight and curly hair." If she was born with it, it wasn't all she was born into. Her father, Frank Kurtz, was one of the most decorated bomber pilots of World War II, an authentic war hero who flew the legendary B-17D in the Pacific Theater. His plane, called the Swoose, after Kay Kyser's hit song about a hybrid "half swan, half goose/ Alexander is a swoose," also gave Kurt's daughter her name. Kurtz, a diver on two American Olympic teams, once had to force-land the Swoose in the Australian bush, saving the lives of his riders, a touring foce of congressmen, one of whom was Lyndon Johnson, who didn't forget. When Kurtz got home his little girl was named after the plane, and she went from military base to military base, from Muskoota to Tampa to Wichita, putting her in a world by herself.

"I must have missed three quarters of the sixth grade out of just fear," she says. "I hated school." Her loneliness gave her some kind of courage though, and in high school she began acting: "The Skin of Our Teeth." "I always wanted an 'Ah, Wilderness!' family," she says, "lots of people asking each other, 'Where are you going tonight?' and there I was by myself." On her own, though, she began acting and picking up the experience she needed to show her complexity and hard work on stage. At 18 she won first prize doing Euripides' "Alcestis" at a southern California drama teachers festival.

She took hard work and did summers at the O'Neill in Conneticut. Critis said she had the wild power to explode and the self-disicipline to restrain herself and she got the kind of reviews that speak to an important actress' progress.

In 1978, she saw Lanford Wilson's "Fifth of July" in performance at the Circle Rep Theater in Greenwich Village and she loved it, didn't give it another thought. "Then," she says throwing her head back, her red hair flaring, "suddenly, last summer -- I was playing in 'Summer' [by Hugh Lenard] and they called me up and said they were taking the play to Broadway. I had 17 days of rehearsal, of which I could only work 14 because I was doing the other play on weekends. So my main problem was just to remember my lines but I did, and at the first run-through, I knew." The audience stopped her for applause at one, two, three points. By the time she was in previews she knew she had the part right, and then came the reviews, the ovations, the Tony.

Swoozie Kurtz walks on stage. She moves her feet like a plastic walking dog, her legs stick like white rubber out of a satin sunsuit, her feet in pink fluff slippers. "Oh God!" she says, "will you look at that ----ing sun. I fry just like a starfish." The audience bursts into a noise that goes beyond laughter. Kurtz goes on and they will take her home.

"They keep on offering me this money," she says. "I can't believe it. I just turned down this major TV show in Hollywood, you know, and just this big, big, big money and how could I not do it? But I couldn't do it. I mean, here I am and I'm a star on Broadway and nobody knows me and they still ask me when I go to auditions, 'Excuse me, what's your name? What have you done?'" She laughs hard. "But I'm doing exactly what I love doing, and I've got to do that because you can't do dreck and preclude doing what you want to do. I don't know what else I could do except what I've got to do.

"I don't know where I get the courage to do it. It's just like," Kurtz says, "it's just like that Feiffer cartoon, where a man's hanging onto a skyscraper and he's about to jump to another, and he says, "I can't do it, I can't do it." She stands up and cluthes a skyscraper. "I can't do it!" And leaps. She smiles, breathes out, sighs, grins. "Aah. I've done it."