Ethel Merman recalls in her current autobiography how movie censors mangled some of Irving Berlin's Broadway lyrics when his songs were used in films. "She started a heat wave, by letting her seat wave" became "She started a heat wave, by letting her feet wave."

Seats are still waving and censors still long to turn them into feet. This of course is the age of television, and of showing rather than telling, and that brings us to one of the key censorship question of the second week of July in the year of our Lord 1978.

The heat wave is at WETA and it was brought on by three minutes that have been cut out of "From Paris With Love: An Evening of French Television," which WETA produced, with the cooperation of the three French TV networks, for PBS stations to show tomorrow night at 9.

What was seen in those three minutes that will not be seen on the air? About that there is disagreement. To some degree it is a matter of the underthings which the chorus girls at the Crazy Horse saloon may or may not be wearing as they dance about and then lie about on the floor, waving their legs in what some describe as an artful and abstract geometric fantasy and what others construe as a wanton and salacious display.

On the wanton and salacious side we find that Ward Chamberlin, WETA president and the man chiefly responsible for the legs on the cutting room floor.

Chamberlin said the segment displayed human flesh in such a way as to be "offensive to stations and to our viewers."

The scenes, which would have aired after llp.m. (the whole program is three hours long), were indeed shown on French television without precipitating a national crisis, moral or otherwise. So why can't they be shown on American TV? "I haven't the foggiest idea," Chamberlin says. "I don't run French television."

In the sequence, from a French series called "Paris By Night," there do remain shots of bare-breasted dancers as photographed at other clubs on the Champs-Elysees. It was just those three minutes at the Crazy Horse that Had To Go.

"This editing doesn't do a damn bit of damage to the program," Chamberlin says. "Besides, it wasn't French culture they were showing but an American version of French culture. I've spent a lot of time in those French night clubs and any night of the week you'll find 70 percent of the people are American tourists, 20 percent are Germans and 10 per cent are French. At least, that's how it was the last time I was there."

The last time he was there was "about 10 years ago," Chamberlin says.

Backing him up on this issue is Joyce Campbell, the station's new program director and the replacement for Fred Flaxman, who resigned last month but who is executive producer of "From Paris With Love."

"I am one of the great libertarians in television," Campbell says. "I've gone to the wall to keep all kinds of things in. In fact, when I went to the screening of this program, I had already rehearsed my reasons for not editing anything out. But then I saw it and I really wanted to take it out. To me it just seemed gratuitous vulgarity. It also, from a woman's point of view, seemed to be sexist vulgarity."

By now you are dying to know precisely what appeared on the screen to cause great libertarians to call for the film editor. Unfortunately we do not know exactly what appeared on the screen but must rely ob eyewitness accounts.

One eyewitness account: First the camera beholds about 16 showgirls dancing. Their only item of apparel is "a small triangular black patch" which induces "the appearance of frontal nudity." Then the ladies lie down and see their legs swaying in time to the music. "It is sexy but not sexual and 'I, Claudius' went much further."

Campbell did not find it quite so innocent. "First you see a group of chorines who are standing up and, well, when you see them from the front, they look naked except for two leather straps. They're wearing sort of semi-bikini bottoms and it looked to me like you could see pubic hair."

Chamberlin says the footage includes anatomical "expanses . . . not shown even on public television before." But he also said he thought it was "pretty entertaining" and quite a stunt."

But he ALSO said, "Anyone who wants to see it can go to the Crazy Horse himself."

Discussions about whether to cut or not cut the sequence reportedly blossomed into full-fledged shouting matches. Various staff members were recruited to look at the three-minute orgy and make judgements. "I really felt strongly it shoudn't be in there," Campbell said. "I felt insulted. But various people here said it did not offend them personally."

She said she did not think there was "a compelling reason of artistic integrity" to leave the footage in.

Flaxman did not want to talk about any of this and besides, he's leaving for France on Saturday.

"Let's just say my plan is to take my immediate future productions to PBS through KQED in San Francisco," Flaxman said, "and leave it at that."