"When we deal with others individually, we can be civilized," said Lebanon's Shiite Amal militia chief Nabih Berri in a recent interview as he mused about the violence that so divides Lebanese society. "But when we deal with each other as groups, we are like savage tribes in the Middle Ages."

He spoke before the latest eruption of violence, in which Christian militia killed scores of men, women and children at Palestinian refugee camps in Beirut, according to witnesses, in attacks Friday night and yesterday morning.

The weekend killings were only the most recent bloodshed in the war-shattered country, where the historic split between the Christian minority, which is economically and politically predominant, and the Moslem majority has contributed to a decade of civil war, factional clashes and Israeli military actions ranging from small-scale retaliatory raids against Palestinian guerrillas to Israel's invasion in June.

Even the charges of massacre this weekend at the Shatila and Sabra refugee camps, where thousands of Palestinians were trying to rebuild their lives after the devastation wrought there by Israel earlier this summer, were not new. Massacres have been laid to both the Christian and Moslem communities in Lebanon, none more brutal in recent history than during the 1975-76 civil war.

The trigger for the conflict, in the view of many observers, came in April 1975, when a busload of Palestinians attending a funeral was ambushed and killed by a rightist Christian group.

By the end of the year, full-scale civil war between Christians and Moslems, with casualties in the many thousands, had led to the notion of possibly partitioning Lebanon into separate Christian and Moslem states.

In January 1976, Damur, a pretty and once prosperous predominantly Christian town of about 30,000, was captured after a week-long siege by Palestinian and Moslem Lebanese troops who controlled most of the surrounding area at the start of the civil war. The Christians were driven out as the invaders looted the seaside town and set up a Palestinian stronghold dominating the coastal road into Beirut.

Casualty estimates ranged as high as 500 dead and at least twice as many wounded; the pillage was said to be total. Damur was a stronghold of Christian ex-president Camille Chamoun, who was forced to flee his house near the town.

The Palestinian and Lebanese leftist forces originally overran the town in retaliation for Christian rightist assaults that leveled Karantina, a Moslem slum area at the mouth of the Beirut River in Christian East Beirut, and the Christian seizure of a Palestinian camp north of the capital a few days earlier.

Some months later, after the intervention of Syrian troops in Lebanon, a move that enabled the Christians to retain control of the government, Christian Phalangist forces under the command of Bashir Gemayel intensified their siege -- begun in January -- of the strategically located Tal Zaatar refugee camp, a Palestinian enclave in a largely Christian area southeast of Beirut.

Relentless shelling and assaults by the Christian attackers, who already had overrun the nearby Jisr Basha Palestinian refugee camp, had cut off Tal Zaatar's remaining defenders from resupply of water, food and ammunition. About 1,000 wounded Palestinians were trapped in the camp's battered bunkers, and several Red Cross attempts to evacuate at least some of the wounded were delayed or obstructed by Christian shelling and other tactics.

On Aug. 13, the day after the camp fell, Gemayel acknowledged that "acts of terrorism and barbarism" had been committed by his forces after the camp fell.

Approximately 1,000 to 3,000 persons, many of them women and children, were killed during the worst days of the siege and the fall of the camp. Charging that the camp was a center of Palestinian terrorism, Gemayel said the "abuses" committed by his men should be measured against guerrilla atrocities against Christians that were begun from Tal Zaatar.

Gemayel became a casualty of the country's continuing violence last week. The list of possible suspects in the blast at his Phalangist Party office ranged far beyond his obvious Moslem and Christian foes, attesting to the scope of enmity still keeping peace at bay in Lebanon.