THE BEAUVOIR SCHOOL knows when parents have made their children practice for its nursery school admissions test. The tots tell. "My mommy made me do this before I left home," a child has been known to blurt out. To Jean Crawford of Beauvoir's admissions department, that's the giveway: The parents privately bought the standardized test to put the little ones through the drills.

That should suggest how far some parents will go to get their children into Washington's private school network -- while others just as intensely defend the public schools in a summertime living-room debate whose results will make a difference in September's classrooms.

James Hellmuth, a graphics designer who lives on Northhampton Street NW, is one of the public school defenders. His two daughters are among 1,067 white children who attended D.C. schools above the sixth grade this year.

"I'm an old line Democrat," he says. "We could find the money if we had to, but I don't like the elitism of private schools. I'm thoroughly convinced that a kid is what he makes himself in terms of the happiness he's going to have in life."

One daughter, Kimberly, 13, an eighth grader at Alice Deal Junior High says she is proud to be at public school -- but she is hurt by the taunts of friends who attend private schools. "They cut me down because I go to public school -- they say it's dirty and rotten and that our teachers are stupid and sit around all day."

So the arguments go -- middle-class parents who coolly discuss great national issues becoming emotional over the merits of public or private schools -- and so their values are passed on to the next generation. It is a debate that often brings out the worst in the parents -- guilt, self-righteousness, anger, defensiveness, deep feelings about race, class, family.

And misconceptions. They abound.

A parent concerned about his child's ability, for example, blames the local elementary school. But he is unaware that math scores for the child's class are two grades the national norm. Some parents who complain most bitterly about the District public schools, in fact, acknowledge that they have never been in one.

By the same token, middle-class parents with children in public schools often seem willing to overlook some of their failures.

Only a minority of families in metropolitan Washington are caught up in this emotional dialogue. Private school is not a considered option for the majority of families who, for reason of lifestyle preferences, housing costs or the reputations of the public schools, choose to live in suburban neighborhoods.

And few of the families of the 100,300 black children enrolled D.C. public schools have either the financial means or the desire to choose private education.

But the Northwest Washington's middle class -- blacks as well as whites, lawyers, doctors, members of the media, lobbyists, businessmen, politicians and senior civil servants -- private school has become the alternative to a public system that many of these parents consider inadequate.

One out of two white District children, one out of 11 black District children and one out of seven of all children, or 18,274 out of 123,636, attend private or parochial school.

While enrollment in D.C. public schools has dropped by 14,600 pupils since 1977, enrollment of D.C. children in nonpublic facilities has risen slightly and attendance at area parochial schools has stabilized after dropping steadily throughout the 1970s.

Statistics suggest that private education is more deeply established in Northwest Washington than in most other American communities. In the inner cities of all American metropolitan areas, only one out of five white children and one out of 40 black children attend private schools at the junior and senior high school levels, a much lower percentage than in the District of Columbia.

That middle-class families in this area sometimes take extreme measures to avoid public schools for their children is evident from the stories of parents interviewed for this article. These parents include:

A couple who sold their house to pay for private school for three sons.

A member of the D.C. School Board who recently withdrew her child from a public school and enrolled him in a private school.

Jewish and Baptist couples who enrolled their children in parochial schools in which their children are exposed to Roman Catholic religious instruction.

What drives parents to take such steps? Perceptions about the quality of education?Concern for the physical safety of the children? Status? Race? Or all those things?

Those are the questions best answered by children, parents and teachers themselves. Acceptance.

When Alexis and Alaire Rieffel decided to send their 5-year-old son Mark to the public school in their Dupont Circle neighborhood, they were prepared to work hard to make the experience a success.

Ross Elementary, at 17th and R Streets NW, reflects the racial and social stresses of an area undergoing change through housing renovation and real estate development. The Rieffels are white, middle-class professionals -- he works for the Treasury Department, she is an attorney. All but a handful of the families served by Ross are poor blacks or Hispanics, street-hardened by the struggle for economic survival in the inner city.

The Rieffels were determined to get involved with Ross and with Mark's education despite this clash of culture and class. They crusaded to keep other middle-class families at Ross and organized rummage sales to raise money for the school. Alexis Rieffel taught French as a volunteer at Ross. Alaire headed the parent-teachers association. Last year, she was elected to the D.C. School Board from Ward 2.

Several months ago, the Rieffels withdrew Mark from Ross and enrolled him in the second grade of Georgetown Day School, a private school with a tuition of $2,795 a year.

School Board member Alaire Rieffel still is not sure her son has told her all the reasons he felt ill at ease at Ross. His teacher went out of the way to help him, and there were no complaints about academics. Mark seems ahead of his class at Georgetown Day School in English and math.

But after other middle-income families had moved their children out earlier in the year, Mark was left as a minority of one among children of very different back-grounds. It was then that "something fell apart from him," says his mother.

Alaire Rieffel knows that some children made fun of the Syrian bread Mark took for his lunch, and she is sure that "there were teachers who wanted us out -- who resented parents who were as involved as we were."

Now, at Georgetown Day, what "seems to strike him is a feeling of social acceptance," she concludes. Quality of education.

In Northwest Washington, this is a buzz phrase used by many parents to explain why their children are in private school.

For Sally (who requested anonymity) -- a mother who expects to pay $14,000 next fall to send three children to Washington private schools, two day students, one a boarder -- quality of education means academic achievement and "moral values."

"You don't get Latin in public schools" she says. "They say you score high on Scholastic Aptitude Tests if you have had two years of Latin, and all three of my kids are taking Latin. That and medieval history."

Sally's views suggest one problem of the public schools, that of perceptions.

Children at District schools can and do take Latin and their academic achievement record is better than some private school parents believe.

Children are taking Latin at Alice Deal Junior High and Woodrow Wilson High, the integrated Northwest Washington schools that Sally's children would be attending if they had stayed in the public system. At Wilson, 47 children are enrolled in Latin, including eight who are taking a third year.

About two-thirds of Wilson's senior class has taken advanced placement courses for college. And Wilson sends about two out of three graduates to four-year colleges. This year's graduates have been accepted at Harvard, MIT, Smith, Amherst, Brown, Williams among others.

Sam Smith is publisher of the D.C. Gazette, former president of the John Eaton Home and School Association, a community activist and columnist who has crusaded for improvements in the public school system.

Next year his son will enter Sidwell Friends, considered by many to be the cream of Washington's private schools.

"If you want to take a political position, don't do it with yours kids," he says.When the question came up of what to do when their son completes seven years at Eaton this month, Sam and his wife Kathy visited classrooms to get a first-hand evaluation.

They found Georgetown Day "too unstructured." But they also ruled Alice Deal, the public junior high school.

"I'd go batty in a place like that," says Smith. "In English the kids were learning four classes of conjunctions. Do you know what these are? It's an easy way to teach, but at the junior high level you need more than categories and definitions. You need to learn how to think. Public school teaching emphasizes rote learning too much."

Smith is discouraged. Many parents view the public school situation as "hopeless," he says. "I've told parents, you're not going to get anywhere until you have as much influence as liquor dealers."

Social status.

"Where your kids go to school is the way you identify yourself socially." The speaker is an unusually frank Cleveland Park mother who adds that "it is impossible to deny that snobbism and connection play a part [in admission to some private schools] if you have one grain of truth in your bones."

"When people pay $200,000 for a house they don't figure on sending their kids to public school," said a teacher, "Private schools becomes part of the lifestyle."

Personal safety.

At Woodrow Wilson High, in which 450 whites are enrolled out of 1,700 in the school, there was a stabbing and a knifing on school grounds this year.

A number of white Wilson undergraduates and graduates interviewed for this article said the racial harassment is a daily occurrence there and that school authorities seem unable to cope with it.

Jane Shumate, a Wilson graduate now at Princeton, described an attack by black girls on a white gym teacher -- "They cut up her face with fingernails -- her face was scratched up pretty bad."

Last January, Principal Reginald Moss of Alice Deal Junior High met with parents and sixth graders from Lafayette School for an orientation meeting about Deal.

Most is black. The sixth graders at Lafayette are mostly white, and many had heard scary tales about tough kids at Deal -- some of them from their brothers and sisters.

Moss dealt with the problem head on. When they got to Deal, Moss explained, there would come a time when some larger kid would demand to "borrow" a dime.

"That is extortion," said Moss. "When that happens, you have to stand up and have guts. If you can avoid it, don't loan the money. But if the kid is bigger than you, give him the money. If you do that, the next stop is my office to report the incident."

A sixth grader wanted to know if the bigger kid would retaliate against him for filing the report.

"There has never been a case of repercussions. That's why we're successful," Moss said.

Moss runs a tight ship at Deal, and is proud of it. He suspends children for fighting, requires hall passes and pushes criminal prosecutions when necessary.

Racial incidents, common at Deal half a dozen years ago, far fewer today.

"A lot of people didn't understand [at the start] that this has nothing to do with color," says Moss. "We aren't singling out black kids. It's just that there is no bending the policy for anybody."

"You know what? He'd been in a fight," Sam recalled.

Race.

A number of elementary public schools in Northwest Washington have predominantly white enrollments. But as white children move into less white junior and senior highs, many transfer to private schools.

At Horace Mann Elementary School, a mostly white, middle-class school, about three-quarters of this year's sixth grade applied to private schools in lieu of matriculating to Alice Deal, in which 350 of the 1,000 students are black.

Whatever the justifications for the public and private systems of educating children, few parents on either side seem pleased that such a situation exists.

"I really resent having to go through this," said a senior government official who has switched his child from a D.C. elementary school to Potomac, a private school in Maryland. "I always thought private school was for damn preppies, and it makes me mad that there isn't sufficient excellence in the public school system."

Some who have seen both systems feel parents overemphasize the value of private school. A teacher who has worked both sides of the educational street said D.C. public schools "can't come close" to private schools in academics. But this same teacher said that parents show "a great lack of confidence in their kids and in life" with their do-or-die stress on getting children into private schools that are more protective and orderly than their public counterparts.

Wanda Washburn, wife of Federal Communications Commissioner Abbott Washburn and membr of the Woodrow Wilson Home and School Association, speaks of a "sort of sickness in the system."

"It's a bad thing when you have more private than public schools in a community," she says. "Public education is one of the gifts of this society. It's the great leveler, and you don't get the same values or sense of national purpose from private schools."

Charlie Mott, who graduated from St. Albans a year ago, thanks that school for getting him where he is today: at Princeton. But Mott, for one, "would give more credit to students and parents than to the educational process . . . I don't think school itself is what inspires people."

Jessica Kuttner, who graduated from Wilson this mouth, has been accepted at the University of Maryland. Her philosophy doesn't seem all that different from Mott's:

"If you succeed at Wilson," she says, "it's because you're geared to going out and getting it . . . you're used to hard knocks. You learn to cope, to adjust to the harder side of life. It makes an individual grow up faster."