The Circle Theater is jammed to the aisles for the last day of "Casablanca" and "To Have and Have Not." Lauren BaCall tilts her head, looks Humphrey Bogart in the eye, and says, "You know how to whistle, don't you, Steve?" Suddenly, over your left shoulder comes a voice: "Listen to this -- the next line is really terrific!" sThe spell is broken.

Time was when any theater-goer who talked during a movie would be shushed promptly by those who sat around him. Now they are too busy talking themselves to notice.

And what ever happened to that usher who always seemed to be at your elbow the moment you set your friends howling with a witty remark or draped your legs over the empty seat in front of you? He zapped you with a flashlight beam, and you got the message. Under the tutelage of such flashlight-toting ushers, a generation learned its movie manners.

As you grew up, you found there was a reason for the rules. Once the lights dimmed and the chatter subsided, you were transported to a world as close to dreaming as you could get without shutting your eyes. The rest of the audience disappeared in the darkness, and you were swept into the movie.

You were alone on the moors with "The Hound of the Baskervilles"; you paled with Melanie as she lay dying in "Gone With the Wind"; you thundered across the plains to "Fort Apache" as if your scalp depended on it; your body ached for Paul Newman in "cat on a Hot Tin Roof." Every experience was yours personally. Only the audience's collective gasps, screams and laughter yanked you out of the action and back into your seat.

Nowadays, you're lucky if yo can follow the plot for all the distractions.

Halfway through "Ordinary People" at the Janus 3, the audience has quieted down to intermittent sniffling, but the ushers are hanging around blathering outside the doors. So much for the old-fashioned keepers of the peace and quiet.

We have forgotten our movie manners. The Me Generation has had something to do with it; and certainly television has inspired some bad habits. Interruptions are endemic to TV viewing: Shows require minimal attention and play to family wisecracks and editorializing, with frequent pauses for Robert Young pushing Sanka and Karl Malden trumpeting American Express.

A trip to the movies is no longer a visit to fantasy land -- it's more like watching TV in an airport lounge.

"The Harder They Come" is making a rare daytime appearance at the Biograph. A middle-aged couple who once visited Jamaica is sitting behind you: "Oh, look! Isn't that the hotel we stayed at?" "What was the name of that restaurant with the great seafood?" "I just love those native singers!" On your right, a young man is explaining to his companion the intracacies of the recording business. When Jimmy Cliff is offered $25 for the rights to his hit record, the young expert volunteers that "Usually, musicians get a percentage deal. $25 is way too low." The trio to your left is talking and laughing even when the movie is anything but funny, and the woman in front of you keeps asking, "What'd he say?" Each time she asks the question, she misses another line.

Some people try to keep their conversations private by whispering. It never works. "Wooshawooshawoosh" competes with the dialogue, and every so often something on the order of "Doesn't that guy in the green look like Fred?" bursts through.

"Raging Bull" is playing at the Old Town, and down the aisle come young marrieds with three kids and a grocery bag full of homemade popcorn. You know you're in for two hours of crinkling and rustling, potty runs and delicate explanations during the movie's blizzard of obscenities.

Then there are the people who wander in late -- a subject unto itself -- and loudly announce to their companions that they can't see a thing. They let their eyes adjust to the darkness and argue about where to sit, all the while standing halfway down the aisle between you and the screen. They generally have to stop again to get their bearings if, say, the elevator door opens in "Dressed to Kill" just as they are climbing over you to get to a seat at the other end of the row.

When the distractions become too much to bear, you can try to fill in for the usher of old, but you'll be at a disadvantage without his uniform, his flashlight and his ability to tower over offenders.

Although Alec Guinness is having a fine romp with the "Lavender Hill Mob" at the Capitol Hill Cinema, the fellow behind you is tired of trying to fathom the cockney accents. "Come on, baby. Let's go to my place," he says to his date. She's not interested, but he keeps it up. Finally, you turn and give them a meaningful glare. The patter continues: the only soundtrack you can hear is, "Let's blow this place, sugar," When at last you venture a discreet "shhhhhhhh," you find yourself at war: "Did you hear that? This a--h-- told me to shhhhhhhh! Whadda you mean telling me shhhhhhhhh? I paid my money same as you. Nobody's gonna tell me what to do. F---- you!"

To be sure, audience participation has its place, notably at kiddie matinees and midnight cult films, such as the "Rocky Horror Picture Show," or "Dawn of the Dead." But going to the movies isn't what it used to be, and viewers may stop going altogether if it gets much worse. High decibels, rather than high prices, may finally drive us out of the theaters and into the waiting arms of the home videocassette salesmen. And it all started with the fall of the house of usher.