Back when Milton Berle was Mr. Television and I was just a lad, I used to sneak out of my room, and halfway down the stairs, I would sit, peeking at the show. One of the things I remember is Berle simultaneously urging the audience to continue applauding and also to stop. In comedy this is funny. In industry it's downright dishonest.

But it is in industry -- specifically the cigarette industry -- that you can now find the corporate equivalent of that old Berle routine. In a recent issue of Parade magazine, for instance, the R. J. Reynolds Tobacco Co. ran a full-page ad headlined, "Does smoking really make you look more grown up?" The answer, as any kid can tell you, is yes, but the ad did not say that. Instead, in a cutesy fashion it said, "a fifteen year old smoking a cigarette looks like nothing more or less than a fifteen-year-old smoking a cigarette."

The ad turned parental: "Even though we're a tobacco company, we don't think young people should smoke. There is plenty of time later on to think about whether or not smoking is right for you."

Notice. There is not a single mention of cancer. Not a word about heart disease. Not a hint that smoking can cause emphysema. Just some cleverly worded phrase about there being time later on to decide. R. J. Reynolds handles the problem of teen-age smoking the way the Reagan administration handles the problem of teen-age sex. It counsels patience and ignorance.

Cynic that I am, I wonder at whom this ad is aimed. I have seen it or a similar one before in The New York Times magazine. I wondered then how many 15-year-olds read the Times magazine anyway. Parade is a different matter. But an ad that is nothing but a block of text is hardly a grabber, and one that does not even mention cancer is just tantamount to a lie. The reason a kid should not smoke is not because it will not make him (or her) appear older, but because in the long run it might kill him.

Cynic that I still am, I think that this ad and others like it are nothing more than a part of the cigarette industry's propaganda offensive. For some time now, it has been running these cute ads about the alleged civil rights of smokers -- and how the poor dears are harrassed by nonsmoking zealots. I agree that there are such zealots, but there are also people for whom cigarette smoke is obnoxious. It makes them sick. As for reformed smokers (my hand is up), some of us are bothered by the smoking of others if only because it makes us want to smoke.

The fact is that when it comes to zealotry, it's not people opposed to smoking who exhibit it, but the cigarrette industry itself. Zombie-like, it walks a straight line to the bank, insisting that there is no proof that smoking causes anything other than stained teeth. Recently, for instance, when it was reported that the government is spending $5 million a year on research for a "safe" cigarette (compared to the nearly $3 billion the industry spends on advertising), a spokesman for R. J. Reynolds was asked if his company was also looking for such a cigarette. "I don't know anything about it," said David Fishel. "We don't know of anything that makes a cigarette unsafe, so how could we be working toward a safer cigarette." Where do they find these people?

The same R. J. Reynolds that sponsored the ad in Parade also makes Camel cigarettes. For its ads, there is no huge block of text, but rather a picture of a he-man mountain climber taking a cigarette break. If the company were sincere about discouraging teen-age smoking, it would illustrate ads ostensibly aimed at young people just as graphically -- with maybe a picture of a cowboy heading to the last roundup because of lung cancer.

For the first time, this year, lung cancer is supposed to overtake breast cancer as the leading cancer killer of women. No one knows how to avoid breast cancer, but avoiding most lung cancer is hardly mysterious. Smoking is a cause; not smoking is a prevention. It could hardly be more simple. Yet the cigarette industry blithely pretends otherwise. Rather than urgently warn kids of the dangers of smoking, it runs sanctimonious ads telling them merely to wait. "Why be in such a hurry?" the ad asks. The answer is easy. Because people are dying.