What was going on when I was born?

Walt Disney Productions, in an apparent move to avoid being taken over, said today that it had agreed to acquire the Arvida Corporation, a prospering community and resort developer, for $200 million in newly issued stock. Disney has been the subject of takeover rumors for weeks. Saul Steinberg, chairman of the Reliance Group, owns 12.1 percent of Disney's common shares and has said he intends to acquire up to 25 percent of the company. Ron Miller, Disney's president and chief executive, said at a news conference today that the Arvida acquisition had not been taken to thwart Mr. Steinberg. However, the Bass brothers of Texas control 70 percent of Arvida's stock, which is privately held, and could receive a stake of as much as 6.9 percent in Disney through the Arvida sale.

The Government action is its biggest, most complete defense of a troubled bank. Page D15. CHICAGO, May 17 - Unable to stem an outflow of billions of dollars in deposits and mired in persistent rumors that it was about to fail, the Continental Illinois National Bank and Trust Company today won support for the biggest aid package ever assembled by the Federal Government. The assistance - $2 billion in new capital and an expanded line of credit for $5.5 billion - will continue until a permanent solution to the bank's problems is achieved or until a buyer can be found to take it over. In addition, the Federal Reserve System, which supervises the nation's commercial banks, has agreed to meet any ''extraordinary liquidity requirments,'' Continental said.

An article in some editions yesterday about an art sale at Christie's misidentified the purchaser of Manet's ''Portrait of Madame Brunet'' and incorrectly described his output of figure paintings. The work was sold to a foundation in the Boston area that prefers anonymity, and it will be on long-term loan to the Boston Museum of Fine Arts. He produced many figure paintings; this was one of the few still in private hands, according to Christie's.

Ignoring a last-minute plea from President Reagan, the House of Representatives voted overwhelmingly today to reject a $95 million proposal for a new nerve gas weapon. The vote, 247 to 179, came on an amendment sponsored by Representative Ed Bethune, an Arkansas Republican. The money was eliminated from a $208 billion authorization bill for the Defense Department as the House debated the legislation for a third day and then recessed for the weekend. In addition, Congressional officials said today that a Senate subcommittee had given Mr. Reagan another setback by approving funds in a closed session for only 21 MX missiles, instead of the 40 the President had requested for the 1985 fiscal year.

Interest rates rose yesterday, despite a generous provision of credit to the banking system resulting from loans to the Continental Illinois National Bank and Trust Company by the Federal Reserve Bank of Chicago. The Continental Illinois crisis and the large loans made to the bank by the Fed have added to confusion in the credit markets, where interest rates have surgd in recent weeks. But the Chicago bank's problems have alleviated fears that the Federal Reserve might soon tighten monetary policy. In the past, the central bank has often made credit more plentiful ''during periods of major financial dislocations or during periods of disorderly market conditions,'' according to analysts at Money Market Services Inc., an economic analysis firm.

AFTER yesterday's reopening of the Museum of Modern Art has been duly celebrated and we have finished luxuriating in the knowledge that our artistic roots are once again within reach, it will be time to consider just how those roots are now presented to us, which ones have been extended, watered, trimmed and cut. Make no mistake about it, the painting and sculpture that is the glory of the museum has been charted by a very particular hand. William Rubin, director of the department of painting and sculpture, has approached his task of installing the foremost collection of modern art in the world with complete responsibility and all the courage of his formidable conviction. Knowing that the present installation of 2 floors and 40-odd galleries of painting and sculpture may be his legacy to generations of artists, Mr. Rubin has left nothing to chance. He has emmeshed every work in a complex network of correspondences and cross-references. His installation has a density and control that almost oblige the visitor to consider it as a work of art itself.

A Reporter's Notebook article from Washington on Saturday, about a convention of newspaper editors, gave an incorrect title for Jody Powell's new book. The book is ''The Other Side of the Story.''

Detective Robert T. Gallagher is, as far as anyone can determine, the most decorated detective in the history of the New York City Police Department. In his 16 years on the force, the 36- year old detective with the big brown mustache has arrested more than 1,200 armed offenders. He has received 210 citations for exceptional valor. Yesterday, Governor Cuomo presented him with the first annual Governor's Police Officer of the Year Award, saying the detective represented the ''old fashioned virtues.''

FRIDAY, MAY 18, 1984 Companies A $7.5 billion rescue package was put together for Continental Illinois by Federal regulators and banks to halt the multibillion-dollar run on the Chicago bank. The money, bolstered by unlimited deposit insurance from the Government, is intended to keep the bank afloat until a buyer or some other long-term solution can be found. Continental Illinois has been crippled by poor loans and a string of rumors that have frightened large depositors. (Page A1.) Any buyer would most likely be a foreign bank, analysts said. (D15.) The nation's three top banking regulators were personally involved in putting together the rescue plan. (D15.) Dun & Bradstreet and A. C. Nielsen agreed to merge. Nielsen shareholders will get $1.1 billion in stock in Dun & Bradstreet, which is cash-rich and thus has been the subject of takeover rumors. (D1.)

A Federal district judge today dismissed a suit brought on behalf of the 120,000 Japanese-Americans removed from their homes and detained in camps in World War II. Judge Louis F. Oberdorfer ruled that the six-year statute of limitations precluded the filing of such a suit. The ruling, if upheld on appeal, would foreclose the possibility of the Japanese-Americans' winning compensation in court for the losses they suffered. It focuses renewed attention on bills before Congress that would provide some compensation for the surviving Japanese-Americans who were interned.

The personal income of Americans in April rose five-tenths of 1 percent and their spending rate was up 1.1 percent, recovering from two months of lackluster performance, the Government reported today. The Commerce Department said personal income would have risen even more except for a sharp decline in farm income.

Room 352: Frank Kron, the biology teacher, admired by students, who strive to please him, known among his colleagues as a stereotype of the profession - a case of burnout. ''This is not what I want to do,'' he says, after 19 years in the classroom. ''There is no reward for being a good teacher.'' Room 333: Heidi Abrams, the English teacher, first runner-up in this year's New York State Teacher of the Year Contest, still filled with all the idealism of a relative newcomer. She likes to quote Henry Adams: ''A teacher affects eternity. There's no telling where his influence may end.'' Room 403: Roslyn Olitsky, the chairman of the creative and performing arts department, with more years in the building than anyone else, though she prefers not to reveal just how many. ''Teaching is the only profession where you have to give five performances a day, whether you're ready to go on or not,'' she says. ''It's never dull, my dear.''