On May Day, as 2,000 Communists gathered in Amsterdam to listen quietly to their leaders, thousands of students battled the police trying to plant Red and V.C. flags on the Nat. Monument.

AS a holiday, both seasonal and pagan, May Day goes back thousands of years. Some remnants of this ancient past still survive: on May Day, French gentlemen give their ladies bouquets of lilies of the valley. In Greece, doors and balconies are decked with floral wreaths. In Czechoslovakia, traditional vows…