Dignity is starting to desert the Wall. Doug Osmond has noticed it. So have I.

Doug, who lives in Detroit, visited his mother in Bethesda late last month. One morning, he dropped by the Vietnam Veterans Memorial, as he does each year. Doug is a Vietnam-era vet himself. "I go to the Wall to pay my respects to friends who lost their lives during that tragic war," he said.

Over the last several years, Doug says, he has noticed a "lack of respect given by many of the visitors there." Visitors mug for photographers, laugh, joke, cavort. In the air is a "total disregard for what those names represent," Doug believes.

He did not confront any cavorters on his recent visit, Doug says, because he "didn't want to cause a scene." Still, he wishes that "there was a way we could restore dignity to this monument and show more respect to the people whose lost lives are represented by it."

To see how bad the situation has gotten, I spent most of last Thursday morning at the Wall. I'm afraid Doug is understating the case.

A bus load of high school students from New Jersey had just been unloaded near the Wall when I arrived. Led by four teachers, the students walked down the sloping path to the point where the Wall forms a V.

The teachers immediately began to read names, wordlessly, to themselves. Meanwhile, the students spotted a squirrel hopping nearby.

They immediately named it Monica, as in Lewinsky. The air was full of raunchy cracks and sharp giggles. The teachers did nothing to try to restrain or stop it.

A few minutes later, one young man posed for a photo taken by another young man. The subject of the photo assumed a mock bathing beauty pose. He might as well have been standing in front of the surf at Ocean City for all the solemnity he showed.

About 30 minutes after that, a man walked past. He was chewing on a lollipop. When he finished it, he dropped the paper stick on the cobblestones, where it sat until I picked it up and threw it into a trash can.

Another half an hour later, two high school-aged students were reading names on the Wall. When they came to Harold M. Crowe, they began to caw like crows. To say the least, they were short on reverence.

The incident that bothered me most involved a man of about 50. As he walked past the Wall, he was barking instructions to his stockbroker into a cellular phone.

To be fair about it, these acts of boorishness were exceptions, not the rule. The vast majority of visitors stared quietly and behaved respectfully as they passed the 52,000 names.

Some young people took the scene as seriously as they should have. I overheard one teenager tell another that his grandfather had explained the Vietnam War to him, and he was glad that the memorial showed what a waste of human life it was. But right next to them, one teenager had another in a headlock -- and other teenagers were cheering the roughhousing.

What explains the changing mood at the Wall? Time, in part. Signlessness, in part. The nature of the Wall itself, in part.

The war in Vietnam ended 25 years ago. More than a third of the country was not even alive on the day the helicopters evacuated our embassy in Saigon. So the Wall has lost its sharpness to a large hunk of the population. It is Just One More Monument to many tourists.

The Wall itself and the land it occupies are spare, stark, almost barren. Of course, that is very much by design. The simplicity of the Wall is what gives it such wallop.

But if the National Park Service is willing to erect no-smoking and no-eating signs, why not another that says: "This is a monument to people who gave their lives in the service of our country. Proper behavior is appreciated at all times"?

Such a sign is all the more necessary because the Wall is outdoors. It is not a church and not the Lincoln Memorial. People don't automatically fall silent as they approach it. They might if they were reminded.

If you are planning to visit the Wall today, Veterans Day, I hope you won't encounter any horseplay, or cell phone calls that can easily wait until a better time and place. But if you do, please let me know. If today's column doesn't induce proper-behavior signs, there will be others -- as many others as it takes.

If we do succeed in getting signs erected at the Wall, they will be timeless. Alas, some signs aboard some buses are not.

Andrew Foos, a reader from Alexandria, thought he was dreaming the other day. He saw an ad on the side of a bus that banged the drum for Career Fest '90.

That's right. A fest that was held nine years ago.

Andrew says he has seen Career Fest '90 ads on several buses. He wonders why.

Metro spokesman Ray Feldmann said an independent contractor is responsible for erecting and replacing ads in rail cars and buses.

"Sometimes, if a bus or rail car has been out of service for maintenance or overhaul, an ad as old as six months could inadvertently make it back on the street," Ray said. But nine years? "A little hard to imagine," Ray said.

He asks that people call 202-637-7000 if they see an ad that obviously doesn't belong. Please jot down the rail or bus number before you call, Ray asks.