After 12 weeks of testimony in a trial that often seemed more the stuff of a soap opera than a real-life-homicide, the Jean Harris murder case went to the jury today.

After meeting for 3 hours and 27 minutes, the jury broke for the night, and is to resume deliberations at 9:30 a.m. Wednesday.

Harris, the elegant former headmistress of the Madeira School in McLean, Va., is being judged on charges of second-degree murder in the fatal shooting last March 10 of her lover, Dr. Herman Tarnower, famous creator of the Scarsdale Diet.

The jury was told to consider lesser charges of manslaughter or criminally negligent homicide, despite requests by both attorneys earlier in the trial that Harris be judged only on the charge of second-degree murder.

It will be too bad, in a way, when the drama ends -- rather as if "Dallas" had suddenly gone off the air after the season in which J.R. was shot.

For the Jean Harris trial has been the sort of circus with everything but a dancing bear -- the mob of photographers and television crews who charged the prinicpals like some crazed, mulitfooted beast; the crowds lining up daily ropes adjoining the courtroom.

There have been a defense attorney with a flamboyant gift of gab ("She's a wounded bird," he said of his client, "a wounded bird trying to fly, and anyone who doesn't see that doesn't have a heart"); a high-minded but bumbling prosecutor who has looked down at the podium, throughout this trial, for nonexistent notes.

There have been a celebrity doctor, a headmistress from a fancy school, a love triangle, allegations of drug abuse, an Other Woman, a stormy night, a .32-caliber pistol, a pair of servants with the ability to be condescending in English and French. It has been the story of an Older Woman shunned by an Older Man for a younger rival. It has become, for better or worse, a feminist cause.

Harris, 57, has been in court since October, including pretrial hearings, charged in the shooting death of her lover of 14 years in the bedroom of his Westchester home.

The prosecution, noting that Tarnower had been seeing another, younger woman, calls the shooting "intentional," the act of a jealous, enraged woman. The defense maintains it was a "tragic accident," a suicide attempt gone awry. t

Today, in a four-hour charge to the jury, Judge Russell R. Leggett reviewed the evidence, which was based on the testimony of 91 witnesses.

He also took some time explaining second-degree murder, punishable in New York state with 15 years to life. Conviction on that charge would prevent Harris under state law from receiving the $220,000 left her in Tarnower's will.

"The indictment reads Jean Harris . . . did cause the death of Herman Tarnower with intent to cause death," the judge said. ". . . That means her conscious intent to cause death . . . . The prosecution must prove beyond a reasonable doubt, the defendant acted intentionally."

The jury consists of four men and eight women -- and women, a noted defense attorney once said, are often harder on other women than on men. Four of the jurors, like Harris, are or have been teachers; 10 are married; two are widowed; eight are white, four are black.

The foreman is a bus mechanic; others are a computer operator, a systems analyst, a nurse, a restuarant worker. None seem to belong to the social circle inhabited by Harris and Tarnower, who lived in a $500,000 home and roamed the globe.

Some jurors, throughout the trial -- particularly since the reading of the Scarsdale letter -- have seemed hostile to the defense; two others, while Harris was on the stand, wept.

In court today, Harris, who has wept repeatedly throughout this trial, had no tears. She sat composed at the defense table in a blue suede suit, her pale blond hair coiffed. There were no outbursts, no muttered asides.

But there had been, early this morning, before court began, an episode that seemed in keeping with the soap-opera aura of the proceeding. Walking toward the courtroom, having endured a mob of photographers who charged her in the lobby of the courtroom, Harris collapsed in the hall. As an attorney tried to help her, she cried.