With short, deliberate steps, the 1,800-pound bull paced through a maze of shelves crowded with $100,000 worth of crystal without disturbing as much as a single glass ashtray.

Suddenly, the set designer, feeling an overwhelming sense of relief, rushed out and grabbed a $30,000 candelabra and, in his haste, smashed it against the side of the case.

The bull, nicknamed Merrill, is the current star and symbol of the million-dollar television advertising campaign of the investment firm of Merrill Lynch Pierce Fenner & Smith. For the past 13 years, the Merrill Lynch bulls have been filmed in herds the size of a New York City subway crowd charging across the plains of America and solo, walking gingerly through a full-scale model of an 18th century maze.

The campaign, first designed by the Madison Avenue advertising firm of Ogilvy & Mather, started in 1970. "I wish I could tell you it was the product of expert market analysis," said Merrill Lynch advertising manager James Walsh. "But it wasn't; it was an accident."

Originally, the slogan "Merrill Lynch: We Look for the Trends" was used. But after the filming, market surveys revealed that the public's awareness of Merrill Lynch had not increased enough to justify the cost of the campaign.

So, left with thousands of feet of film, a writer came up with the idea--almost as a last resort--of using the bull in the slogan as well as in the commercial. Hence, the slogan, "Merrill Lynch Is Bullish on America."

The commercial was first aired during the 1970 World Series, and within two months the same market surveys revealed that the public's awareness of Merrill Lynch had doubled.

Originally, several bulls had been used in a variety of stunts as living symbols of the theme "Bullish on America." But by the time Ogilvy & Mather tranferred the account to Young & Rubicam in 1979, only one bull was in use.

Looking for a new approach, Y&R kept the bull, but changed the slogan to "Merrill Lynch: A Breed Apart."

The commercials featuring the bull stepping through the china shop and finding his way through the maze were part of the attempt to portray Merrill Lynch in a different way, according to Bill Appleman, senior vice president at Y&R. There seemed to be a perception that the quality of service a company gives is inversely proportionate to its size, he said.

"The older commercials were a little macho," he said. What "we are trying to do is to show the public that, despite our size and strength, we are subtle."

Y&R spared little expense in making the point. Almost $100,000 worth of crystal was leased from a California property supply house and, with the comfort of a Lloyd's of London insurance policy, the bull paced through the shelves after only two rehearsals.

Joan Edwards, who has been training animals for 20 years in Los Angeles, started working with the Merrill Lynch bulls when Y&R took over the account.

"We'd never had a challenge like this," she said. "They called me and said they needed a trained bull in three months. We had worked a lot of cattle, but we'd never really schooled a bull."

"I was so hyper the day of the shooting," she said. "I had worked him the bull through a design of the shelves that I'd constructed from Appleman's drawing, but I'd constructed them out of bales of hay and the bull kept stopping to eat the hay." But, she said with a laugh, "They didn't worry about him eating the china bowls."