What was going on when I was born?

Massey-Ferguson Ltd., citing the benefits of an aggressive cost-cutting program, said today that its loss for the second quarter narrowed to $11.3 million from $87 million a year earlier. But the big Canadian farm-equipment manufacturer said sales in the quarter plunged 22.6 percent, to $401.1 million, from $518.2 million in last year's second quarter, reflecting the continuing steep recession in the market for tractors and other heavy farm equipment. The company states its results in United States dollars. Farm and industrial machinery sales fell 20 percent in the quarter, to $388 million, while diesel engine sales fell 34 percent, to $63 million, Massey said.

Under this heading, The Times amplifies articles or rectifies what the editors consider significant lapses of fairness, balance or perspective.

Two American marines were killed and 14 were wounded as savage fighting between the Lebanese Army and Moslem militiamen turned Beirut into an arena of exploding shells, machine-gun fire and snipers' bullets. The Lebanese Army met stiff resistance as it sought to gain control of Shiite Moslem neighborhoods in South Beirut. (Page A1, Column 6.) No change in the U.S. peace mission in Lebanon is called for, according to a Cabinet-level panel headed by Vice President Bush. The panel also told President Reagan, who is on vacation in California, that there was no need to increase the size of the 1,200-marine peacekeeping group. (A8:1.)

For a staid, button-down industry largely unknown to the general public, the factoring business, primary banker to the garment and textile industries, has had its share of dramatic moments in recent years. Only last week, one of the oldest firms - they are called factors - sued its former president, two former employees and a group of garment concerns charging a systematic, five- year, multimillion-dollar fraud. Industry officials say they expect a similar scandal to emerge any day at one of the biggest factors. And late last year, a multiple murder was linked, indirectly, to an investigation of fraud at still another factoring firm.

In London four days ago, a lead seal was put on a custom-made case containing Foreign Office Document No. 93/8/2. The Keeper of Public Records, case firmly in hand, boarded a westbound flight. That afternoon, in a richly paneled office overlooking Fifth Avenue, the seal was broken. The Treaty of Paris had come to New York.

The General Accounting Office today reported that owners of the nation's first major synthetic fuels plant are understating their financial position. The House subcommittee chairman who requested the report expressed concern that this was being done to win increased Government backing. The report concluded that the parent companies that own the Great Plains coal gasification plant in North Dakota are not taking potential tax benefits into account when they say it now looks like the project will not make enough money to pay its own way in the early years. The findings ''raise serious doubts about the extent of Great Plains' difficulties, if any at all,'' said the Congressman, Representative Mike Synar, Democrat of Oklahoma. His panel, the Environment, Energy and Natural Resources Subcommittee of the House Government Operations Committee, is planning hearings on the matter when Congress returns from its summer recess next month.

Members of the New York City Opera orchestra ratified a new, three- year contract yesterday. The vote, which followed what was reported to be an impassioned, sometimes angry discusssion, was 32 to 21. The ratification meeting began at 5 P.M. in the offices of Local 802 of the American Federation of Musicians, and the results were announced at 6:30. The orchestra theoretically includes 69 members, but some positions are vacant and several members did not attend the meeting.

Opposition is mounting to a campaign by beer distributors for an antitrust exemption that would permit exclusive distribution rights in a territory. The proponents, who also include brewers and the teamsters, began lobbying Congress last session for such a bill, following the lead of the soft drink industry, which won such an exemption in 1980 after a long fight. Initially it looked as if the beer interests might have it easier. But last year's session ended without action, and now the industry is locked in battle with tavern and food store owners, as well as consumer groups, who contend that the bill would lead to higher prices. The Justice Department and the Federal Trade Commission have also opposed the bill as anticompetitive.

MINNEAPOLISPeople commonly start eating when their stomachs growl and stop eating when they feel full. The process seems simple enough, but the latest research on appetite control indicates that hunger and satiety actually come as the culmination of an internal chemical battle so complex that it is often hard to predict the winner. In fact, researchers are now discovering that so many biochemical signals contribute to determining when, what and how much people eat, that they doubt whether a single all-powerful mechanism of appetite control will ever be found to help solve most weight or health problems. Rather, specific therapies geared to individual problems with appetite regulation now seem to be the only hope for widespread success. As a clearer picture emerges of the intricate chain of chemical commands that govern hunger, satiety and eating patterns, the researchers are finding that some people have specific defects in appetite regulation that might be corrected by individualized therapy. Using different approaches, it may be possible, for example, to reduce the appetite of diabetics and ever-hungry bulimics and to stimulate that of cancer patients and people with depression or anorexia nervosa, which is characterized by an aversion to food.

GENETICALLY engineered bacteria may be released into the environment soon for the first time in a controlled experiment outside the laboratory. In the next few weeks, scientists plan to spray young plants in a northern California potato field with bacteria modified by the powerful tools of gene splicing. The aim is to help protect the potato plants against injury by frost, cause of millions of dollars of crop damage every year in the United States to corn, soybeans, wheat and citrus fruits as well as potatoes. Because they will be the first deliberate releases, the planned experiments at Tulelake Field Station, Calif., have again focused attention on possible risks as well as benefits of gene-splicing. Many possible uses are being developed for agriculture, mining and other industries. If these uses are ever to be realized, most such uses will require the release of the organisms into the environment.

''The Declaration of Independence, the Constitution and the Treaty of Paris are our three Magna Cartas.

For the first time in the three-year-old civil war, Salvadoran Government officials met today with members of the Salvadoran left. The five-and-a-half- hour meeting took place this morning in Bogota, Colombia, according to a United States official there. After the meeting, Colombia's President, Belisario Betancur, who attended the session, issued a statement saying that it was ''a first effort'' at discussion and that there was ''a possibility that there will be other contacts.'' U.S. Envoy May Meet Rebels At the same time, Richard B. Stone, the Reagan Administration's envoy to Central America, arrived in Costa Rica late today amid speculation that he would meet here with other Salvadoran rebel leaders.