The feminists may deliberate about the problems of aging women, the careerists of the pressures of the job, but in the end, the Jean Harris murder case is about love -- the ancient but engaging question of woman scorned, and what may or may not follow.

So, it was good, after all the tedium of ballistics testimony and medical examiners and such, when a longtime friend of Harris took the stand today and addressed herself to that most paramount -- The Relationship.

Many new details were thus divulged: the fact that Dr. Herman Tarnower, the man Harris is accused of shooting in a jealous rage, had, a year into the relationship, given Harris a "big, emerald cut ring." At the party where Tarnower and Harris met it was -- note the expression -- "love at first take. . ."

But perhaps most central, since this is, after all, a drama with a third leading character -- the notorious Younger Woman -- was the witness' contention that while Harris was aware her lover dated others and "wasn't happy about it," she did accept the situation.

"She stated many times she never felt another woman was a decided threat," said the witness, Marjorie Jacobson, a woman of formidable chic and a Park Avenue address who has know Harris over 50 years. "She was aware that Hy saw other women, but she loved him very much . . . she felt this was just something she was going to have to put up with. . . ."

Former headmistress of the Madeira School in McLean, Va., Harris has been charged with the second-degree murder of Tarnower in the bedroom of his home last March. The prosecution, noting that the doctor had been seeing another woman -- Lynne Tryforos, a woman 20 years Harris' junior -- has called the shooting intentional, the act of a jealous, embittered woman. The defense has insisted the shooting was an accident, a suicide attempt gone awry, and has in fact produced suicide notes Harris left in her home.

"I wish to be cremated immediately," said one, "and thrown away." Jealously has been downplayed as much as possible. The events that caused Harris to drive to her lover's home in Westchester County, Aurnou said in his opening arguments, had little to do with Tarnower and much to do with Harris' low self-esteem plus the pressure of her professional life. "In this case, the answers to the things in Jean Harris' life were in Virginia, not New York," the defense attorney said.

Today, as the defense continued its case, there was an attempt, again, to minimize jealousy as a motive and to highlight instead the pressures Harris felt in her position at the Madeira School. There was also an attempt to present Harris as an upright, honest, "peaceable woman," to which end several former students -- fair-cheeked, adorable, dressed in preppie plaids -- strode down the center aisle of the courtroom as if it were the runway for the local Junior Miss contest, and gamely took the stand.

"She always spoke the truth to the hilt, " said one (Thomas School '74) in an unfortunate turn of metaphor. Another (Madeira '80 and the only black) spoke of honor. "Everyone talked about Mrs. Harris, how strongly she supported integrity, how high her values were."

But by far the best testimony for Harris watchers, who pack the courtroom daily, were the comments by witness Jacobson on the Harris-Tarnower affair and the testimony, by acting Madeira headmistress Kathleen Johnson, of the Madeira School intrigues that the defense suggests led to a form of breakdown.

Jacobson -- tall, elegant, her white hair pulled back into a bun and her wide gold bracelet reminiscent of a small piece of armor -- provided the information about the Harris-Tarnower affair. Included was the always important account of the First Meeting. The two were invited separately to a Jacobson party, a bit of social choreography which must give Jacobson occasional food for thought.

She spoke of her long relationship with Harris, dating back to when their families "had cottages on he Canadian side of Lake Erie." She talked of the times, having gone their separate ways, that they managed to keep in touch. "I did see her at one time when Jeanie was choosen as house mother on a trip to Russia with a group of Choate boys."

Of the Harris-Tarnower relationship, she could not have been more complimentary -- or discreet. The two met in the winter of 1966, she said, and "enjoyed each other" immediately, though, she indicated, Harris did not spend the night at the doctor's home for at least a year. Up until the doctor's death, she said, she never saw him in the company of another woman. In fact, in the spring of '67 or '68, the doctor let Jacobson know how serious were his feelings toward Harris by saying he was building an addition to his home for Harris' two sons.

That picture of doctorly devotion suffered somewhat under cross-examination by Assistant District Attorney George Bolen. He established that Tarnower had, in fact, drawn up the plans for enlarging his home in August 1966, before he had met Harris.

There was also testimony today from acting Madeira headmistress Johnson. A robust, forthright witness with graying close-cropped hair, Johnson had been academic dean at Madeira under Harris and seemed a competent successor. ("We have some balky business," Johnson said, speaking of headmistress problems at one point in a tone that suggested buildings, under her reign, would not balk long.)

On the stand for the defense, Johnson spoke at length of the pressures of being a headmistress. She also spoke of some of the specific pressures facing Harris at the time of the shooting. Harris, Johnson testified, had suspended four senior girls for an unspecified offense the week before the shooting. She also, the day of the shooting, received a letter from a student, which, she said, left her "upset." Harris asked Johnson, in the presence of another Madeira faculty member, to read the letter twice. And when the women suggested she not take the letter so seriously, she did not follow their advice.

"It was as if she had something pulled over her eyes," said Johnson, " as if she didn't here us . . . as if she was cut off."

Contents of the letter were not revealed. And the effect the defense seemed to desire -- that Harris, the day of the shooting, was extremely upset -- once again suffered at the hands of the prosecutor.

"Did you go about your normal routine later that day?" asked Bolen.

"We transacted business as usual," said Johnson heartily.