What was going on when I was born?

Wall Street's ''poison pills'' appear to be deadly medicine - even though no company has actually had to swallow one yet. The poison pill is an increasingly popular defense against takeovers. Though it can take different forms, the basic strategy involves a company giving its stockholders the right to buy shares at a special price, or get other benefits, when a hostile bidder tries to take over the company - making such a takeover prohibitively expensive, or ''poisonous,'' for the would-be acquirer. The defense, and the phrase, emerged in the course of Lenox Inc.'s 1983 battle to fend off a takeover by the Brown-Forman Distillers Corporation - although Lenox ultimately decided to dissolve its pill and accept a bid from Brown-Forman. Still, most takeover experts see the poison pill as a perfectly effective preventative: No company that has adopted the pill has ever had to use it.

The Bank of Boston conceded today that it might have been unwittingly used by the city's organized crime family to launder as much as $2 million in cash. But William L. Brown, chairman of the bank, insisted that there was ''no evidence whatsoever'' that any employee of the bank had ''benefited in any way'' from its dealings with the underworld group. Mr. Brown asserted that his bank's involvement with the group, the Angiulo family, was only a result of ''poor judgment'' by bank employees, whom he refused to name. Seven leaders of the Angiulo group - including the man described by the Federal Bureau of Investigation as its head, Gennaro J. Angiulo - are scheduled to stand trial in Federal District Court here next month on racketeering charges. These charges arise from accusations of murder, obstruction of justice, gambling and loan sharking.

Six New York City transit police officers were indicted yesterday on new charges stemming from the death of Michael Stewart, a 25-year-old Brooklyn man who died after what prosecutors described as a police beating. Three of the officers were charged with criminally negligent homicide and assault. They had been indicted last year on manslaughter charges, but that indictment was dismissed last October when a judge found misconduct on the part of one of the members of the first grand jury. All six officers - among 11 who had contact with Mr. Stewart the night he was arrested and charged with scrawling graffiti on a subway station wall - were charged with perjury. They all pleaded not guilty yesterday in what has become one of the most widely publicized cases involving charges of police brutality in the city's history.

The Securities and Exchange Commission decided today that mutual funds would no longer need prior authorization from the agency to alter the fees that brokers get for selling the funds' shares. The move effectively frees the S.E.C. and the funds from a substantial burden of paperwork. But the S.E.C. stopped short of allowing the brokers themselves to cut their commissions in a bid for more business.

In nominating Beryl W. Sprinkel today to be chairman of the Council of Economic Advisers, President Reagan chose a man who has emerged within the Administration as a loyalist first, and only second an economist. After seven months of uncertainty over the future of the council, the appointment suggests that, from now on, internal disputes over the President's economic policies will be kept behind closed doors. ''He's a company man,'' said Murray L. Weidenbaum, the President's first council chairman. Mr. Sprinkel, who is 61 years old, has occupied the third-highest position in the Treasury, Under Secretary for Monetary Affairs, for the last four years. A Minority of One Mr. Sprinkel is an often jolly, slightly rotund, bespectacled man and one of the country's leading proponents in the monetarist school of conservative economics, which puts him in a minority of one among the Administration's senior economists.

The PNC Financial Corporation, the nation's 25th-largest bank holding company, announced changes in its top management yesterday. The holding company, whose two principal subsidiaries are the Pittsburgh National Bank and the Provident National Bank, said that Roger S. Hillas, now president, had been named chairman, and that Thomas H. O'Brien, vice chairman, would become president and chief executive. The changes are effective April 1, when Merle E. Gilliand, chairman and chief executive, is scheduled to retire.

The Government announced today that hundreds of people had been arrested this week for activities that it said could disrupt national elections next week. Officials said also that more than a dozen top political opponents of Gen. Mohammad Zia ul-Haq, the President, had been confined to their localities. Many were said to be under house arrest as a ''pre-emptive'' step to insure that the elections for a new National Assembly and provincial legislatures take place quietly. General Speaks of Release General Zia, discussing the wave of arrests after it began earlier this week, said that those seized or confined would be released when the elections were completed. The vote is to take place Monday and Thursday.

When Indians led the Rev. Louis Hennepin to the foot of the falls here in 1678, legend has it, the awed Franciscan missionary, the first white man to see it, fell to his knees, unstrapped an altar from his back and said mass. Reacting much like Father Hennepin, many people in this city by the falls gave thanks Tuesday when former residents of a chemically contaminated neighborhood received their shares of the $20 million Love Canal lawsuit settlement. ''It's a milestone,'' Mayor Michael O'Laughlin said in an interview. ''It ends the hysteria. That's all behind us now. We hope the younger generation doesn't remember Love Canal. We want them to remember us as the City of Romance, a great place to visit, a great place to have conventions and a great place to live.''

A dispatch from Dublin yesterday on legislation regulating the sale of contraceptives misidentified Ireland's Minister of Health and Social Welfare. He is Barry Desmond.

IN a week remarkable for its profusion of very good new shows by women artists, young and not quite young, ''Frankenthaler: Works on Paper 1949-1984'' at the Guggenheim Museum is in essence an autobiography that happens to have been drawn and painted, rather than written. It begins not in childhood, but in first youth, with our author fresh out of Bennington as the brightest young woman in town. At 21 years old, she organized an exhibition of ''Bennington College Alumnae Paintings'' at the Jacques Seligmann gallery in Manhattan, and in no time at all hers was the fresh new face that turned up in the company of David Smith, Jackson Pollock, Lee Krasner, Willem and Elaine de Kooning, Franz Kline and Barnett Newman.

-dancers and crackling fireworks will quicken the pulse of Chinatown this weekend as the community celebrates the Chinese Lunar New Year. But China's heritage will be evoked uptown, too, in sumptuous collections of art and in displays of antiques. In addition, the holiday can be celebrated in Chinese restaurants all over town or at home with food from some of Chinatown's best takeout restaurants, as recommended in accompanying articles. The Year of the Ox - 4683 in the Chinese scheme of things - began Wednesday, touching off days of festivities. They'll be especially intense Sunday afternoon, which is when the byways of the Chinese quarter will teem with packs of costumed lion- dancers (symbolizing good fortune), and the noise and smoke of firecrackers will fill the spicy air. In and around Chinatown this weekend, visitors can also feast their eyes on photographs of China by a Chinese- American scholar and paintings by Chinese-American artists. They can watch folk dances or parts of Peking opera, from a sword dance to the drunken queen dance.

A State Supreme Court justice ruled yesterday that the Long Island Lighting Company, as a private corporation, has no legal authority to carry out an emergency evacuation plan for the area around the Shoreham nuclear plant. The company had tried to fill the breach left when New York State and Suffolk County, where the $4.2 billion plant is located, refused to participate in an evacuation plan. Such a plan is required by Federal law for operation of the plant at full power. The decision, by Justice William Geiler, was described by state and county officials as a blow to the chances that the plant would open. The ruling came in a lawsuit brought by the state, Suffolk County and the Town of Southampton.