THE FERVOR Luise Vosgerchian brings to her music once led a reviewer to issue a warning. "A bit of advice to this young artist," he wrote: "Remember that pianos do wear out." The piano survived, but the same intensity that Miss Vosgerchian now brings to Music 51 at Harvard leaves none of her students indifferent.

A keyboard section: a cutbook of figure bass on the piano rack. Miss Vosgerchian points to a twomeasure sequence. "Identify the situation," she tells a student. Her eyes narrow. A tentative smile. She stares into his face to coax the answer out. "Identify," she repeats. "In two words tell what is happening. Isn't it a five-one situation?" The student nods. "Oh it's painful, isn't it," she croons.

Miss Vosgerchian has taught at Harvard since 1959, when she took over the Basic Piano program. For the last three years she has taught first-year harmony in Music 51. In her office, sitting among dulcimers, stringless lutes, a harpsichord, and a chamber organ, she is revealed also as the Curator of Ancient Instruments. But it is the concert career preceding her work at Harvard that best explains her effluent style of teaching. She threatens, exhorts, raises her eyes in anguish, then emerges with a reassuring smile.

"I was born a harm," she says. "I insisted on playing in public a year after I started the piano."

She made her debut with the Boston Pops by announcing herself to the conductor. "I decided I should play with Arthur Fidler," she says, and so she did. "I called him one day and said, 'You don't know me, but I simply must play for you.'"

"I think he was attracted to my nerve," she continues, "for he scheduled me immediately."

HER DEBUT with the Boston Symphony in 1948 was less the product of her own initiative. She was playing at the time with Ruth Passelt, violinist and wife of the associate conductor. The orchestra was in Cleveland that winter when Lukas Foss, the scheduled pianist, was suddenly called away. Miss Vosgerchian was given twelve hours to begin rehearsals. "No woman yet had played in the Symphony," Miss Vosgerchian recalls, "so Koussevitsky insisted I first play in front of Lukas."

The evanescence of concert reputations surprises her even now. It is far more enjoyable, she says, to give a concert in Boston, than in New York. Here she is an "accepted commodity"--in New York you have to break in again each time you play. At a concert recently, Miss Vosgerchain was playing as accompanist to a friend. A tall black woman, the daughter of Roland Hayes, came to her afterwards. "I've never heard of you," she said, "but I simply must have you as my pianist."

"What a generation gap," says Miss Vosgerchian. "A generation and she didn't know who I was."

Still, concert success has not left her visibly selfsatisfied, nor impatient with an "academic" music department. "I tasted all that while I was still in my teens," she says. "For artists going in the other direction, from study to performance, things like that can be meaningful. But finally I gave part of it up for serious study."

Miss Vosgerchian went to Paris in 1949 to study with Mlle. Boulanger. Since her return to the United States in 1956, she has reduced her Symphony work to teach with fewer interruptions at Harvard. When she does perform, she plays more often at college concerts. "I'm not a Horowitz," she says. "But on the university level I can make available a repertoire that students otherwise wouldn't hear."

Years of playing have not overcome all of Miss Vosgerchian's reserve, despite her usual ebulliance. Monday lectures in Music 51 still make her nervous, she says. And when she last played at Dartmouth's Hopkins Center, "You know they wanted so many interviews and photographs!" She makes a face.

MUSIC 51 is run on one apparent principle: that practical facility is as important as theory. Each student accordingly has two small keyboard sections after the Monday lecture. Miss Vosgerchian believes that to "understand" a technique of harmony means little. The mind and ear must be drilled until they can handle it facilely. Only then is a student inclined not to settle for the first harmonization he thinks of. He will be able to choose the best of several.

She preaches the need for regular work. "I abhor this 'laisser-aller' attitude," she says, "that allows students the convenience of cramming and spurts of concentration!" If you have no other time to work, she once suggested, get up at seven.

It is in pushing each student to try the uncomfortable, unorthodox use of a technique that Miss Vosgerchian's vehemence has brilliance. She sits by a student's shoulder at the piano, questioning, wheedling, soothing, demanding that he try an exercise one more way. "You don't think I'm going to let you be comfortable, do you?" she said to a student. "All you can do is to be up against something and use it for what it offers you."

Miss Vosgerchian doesn't exaggerate what can be taught in composition. The technique is explained, the enthusiasm encouraged, but the student must adapt them for his own purposes. "I'll never forget a student of mine," she says. "He had certain disagreements with what I said, but during each lesson he would say nothing. Yet when he came back, the next week, I could tell exactly what he had rejected."

"Such intelligence!" she says. 'He didn't bother to argue, but he kept what he thought was good." Miss Vosgerchian's vehemence is meant to offer a student ideas, not impose them. Beneath an exaggerated manner is a modesty of purpose.