Poland's Communist Party Central Committee, at an important meeting Monday, will carry out a purge of "antisocialist elements," the official press said today.

The focus of the session undoubtedly will be on last week's remarkable events in Warsaw when, in a few dramatic days, the independent trade union federation Solidarity managed to secure the release of two jailed workers and start a public debate on the role of the security apparatus in a communist society.

The official party newspaper Trybuna Ludu said today that "the process of cleaning up the party from people who violate ethical and moral norms, who have different ideological and political views, will be deepened and stepped up" at Monday's one-day session of the Central Committee.

Many party members, the paper said, do not realize that Poland will not return to "the old style of work, old methods of activity, old systems of values." But it also warned that "under the pressure of criticism and various doubtful concepts -- including ideas formulated by antisocialist forces -- some party members have turned their backs on the ideological and political principles of the party."

The workers' victories of the last few days were secured at considerable cost. The already shaky authority of the Polish Communist Party was undermined still further, leaving Poland more vulnerable to Kremlin intervention. Perhaps even more startling, at one point it even looked as if Lech Walesa, the leader of the independent union movement, was losing control of his own supporters.

The culmination of the crisis came Thursday. Walesa tried desperately to persuade workers at the giant Warsaw steelworks to call off their strike, even warning that the government might use tanks and rockets against the strikers if they pushed too far.

The workers seemed reluctant to heed Walesa's warnings of possible disaster as one speaker after another demanded immediate negotiations to curb the powers of the secret police and the prosecutor's office.

Only after the intervention of Jacek Kuron, a dissident leader who had earlier been regarded as one of Walesa's more militant advisers, did the mood change decisively and the workers finally voted to end their strike.

The events leading up to that meeting show how grievances and emotions in Poland can easily get out of hand. But in the end, confrontation was avoided because both sides realized they stood to lose more than they would gain.

Solidarity's leaders also are discovering that while it is easy to whip up the workers' sense of grievance, it is more difficult to control it when tactics require.

Goverment also faces difficult constraints. Partly for domestic political reasons, partly because of the Kremlin's watchful eye, it is usually in a position to make concessions only when under heavy pressure. By that time, it is often too late: the workers have hardened their demands. This frequently plays into the hands of the hard-liners on the other side.

Thus if Jan Narozniak, the young Solidarity volunteer accused by the government of revealing state secrets, had been freed immediately after his arrest a week ago, it is likely that little more would have been heard about what was until then a relatively unimportant affair. But by Tuesday, Narozniak was on his way to becoming a national celebrity as workers demanded his release.

In order to justify a strike in support of Narozniak, however, Solidarity felt it was necessary to broaden the issue. So other demands were added including the freeing of four political dissidents, the appointment of a parliamentary commission to investigate alleged abuse of power by the security police, and the publication of a hitherto secret official report into the bloody suppression of strikes in Gdansk 10 years ago.

After tense negotiations through intermediaries, an emergency joint session of the Communist Party Politburo and Cabinet decided to release Narozniak and Piotr Sapielo, a worker in the prosecutor general's office alleged to have leaked a secret document to Solidarity outlining a strategy for harassing dissidents.

But then began problems that were potentially more serious and raise questions about future relations between the government and the independent union movement.

Exhilarated with one victory, many workers wanted to press their advantage.

Strong opposition to ending the strike came from the Warsaw steel mill, where workers' feelings had become aroused over the security police issue. Having involved the steelworkers in Solidarity's campaign, it was impossible to simply order them back to work. So the ploy was adopted that the strike had been called off but the steelworkers had been instructed to remain out until the government appointed a commission to negotiate all the union's demands.

Now it was the authorities' turn to stand firm. Deputy Prime Minister Mieczyslaw Jagielski hinted very strongly that if Solidarity did not back down, there could be a major confrontation.

Walesa, at union headquarters in Gdansk, had been getting strong signals that this time the authorities were prepared to carry out their threats. He flew to Warsaw, where he was met at the airport by a worried Kuron.

The two went straight to the steel mill, where the workers appeared adamant. "If we back down at this point in our history," one worker said, "we won't be able to look our children in the eyes in 20 years."

It took seven hours of talking to persuade the workers to end their strike. The next morning, several hundred students with sleeping bags were still occupying the administrative building at the university in support of the union's demands, but much of the tension that had been mounting all week had been drained out of the air.

So it has been throughout the last five months of the Polish crisis. Hopes and fears, realism and romanticism alternate with each other as government and workers gear themselves up for a confrontation and then back away from it. The popular mood changes every few hours.

Asked last week whether he felt pessimistic or optimistic about his country's future, one of Poland's leading historians replied drily: "It all depends on the time of day."