At the end of a long and tedious speech to 210 black Jaycees today, John B. Anderson suddenly shifted gears.

He began quoting Theodore Roosevelt, another Republican, who 68 years ago ran a hopeless third-party race for the presidency under the Bull Moose banner.

"It is not the critic who counts, not the one who points out how the strong man stumbles or how the doer of good deeds might have done better," he said. "The credit belongs to the man who is actually in the arena, whose face is marred with sweat and dust and blood, who strives valiantly, who dares, and comes up short, again and again."

It is, he continued, the man who knows "the great enthusiasm, the great devotion and spends himself in a worthy cause, who if he fails, at least fails while daring greatly, so that his place will never be with those cold and timid souls who know neither victory nor defeat."

This is symbolic of Anderson's campaign in recent days. The campaign is no longer a political campaign. It is a human story of a man struggling against impossible odds.

His voice quivering with emotion, he turned today to the young black businessmen and teen-agers in the audience, "Know the great enthusiasm of our time, know the great devotion to which you can give your energy," he said. "Spend yourself in a worthy cause and dare greatly."

Anderson was talking to the audience.But as his words tumbled forth it became increasingly clear that he was talking about himself.

Anderson increasingly sees himself as a bloodied martyr, unafraid to deliver a message to the American political system, a candidate determined to make a "statement." His most eloquent moment comes as he looks inward, at himself and at his lowly place in the presidential race.

"What's wrong with America is that we have so surrendered our country to those who are complacent, to those who have demonstrated importance, to those who fear risk and change," he said today.

"We will tell these people the truth as long as a forum exists anywhere in this country." Anderson said, his booming voice again cracking, "as long as people like you will listen and as long as I have the strength."

With that, Anderson sat down to polite applause. The audience appeared as confused as impressed. Only a third of the crowd rose to clap. By prearrangement, the Compton Jaycees presented the independent presidential candidate an honorary membership for showing "political courage."

Later, Anderson was asked who the critics were he was talking about, those who point out "how the strong man stumbles." He replied that they are the "political pros that look slightingly and askance at someone who does not choose to seek presidency by the traditional accepted route." Anderson, of course, tried the traditional route. But when his bid for the Republican nomination failed, he decided to run as an independent. 'I realize I'm without a party," he said today. "But I'm not a man without a country."

Anderson made his appearance here during a day in which he campaigned in what is normally thought to be hostile country in Southern California. Later, he spoke at a luncheon, sponsored by the California State University department of business and economics, in Disneyland, in the heart of conservative Orange County, and at a steelworker union hall in industrial Fontana.

At a news conference, he tried to counter recent unfavorable findings in national public opinion polls by giving results of statewide polls in some of his strongest areas.

He cited a New Jersey poll by the Eagleton Institute at Rutgers University showing Republican Ronald Reagan with 34 percent, President Carter with 30 percent and Anderson with 25 percent; a poll by the Becker organization showing Reagan with 27 percent, Carter with 26 percent and Anderson with 24 in Massachusetts; and a poll by the University of Connecticut's Institute of Politics that showed Reagan at 29 percent, Carter at 28 percent and Anderson at 27 percent.

"There are about four weeks left in the campaign," Anderson said. "And I'm convinced that there still is time to turn the election around."