Four hundred Boston University (B.U.) students rallied outside their student center yesterday to protest President Carter's renewal of draft registration.

B.U. senior David J. Detmer, who organized the rally, said "we just wanted to have a visible demonstration to add to the ground swell against registration," which Carter has proposed for all 18-, 19- and 20-year-olds.

Speakers at the rally included George Wald, Higginson Professor of Biology Emeritus, and Helen Caldicott, president of Physicians for Social Responsibility.

Harvard anti-registration organizers Wednesday night adopted several "Principles of Unity" for campus activists. The principles include:

"We oppose registration and the draft" (the group vetoed motions to add "at this time" and "at any time" to the resolution.);

"We oppose any nationalistic hysteria that diverts attention from pressing domestic problems";

And "We see registration as part of a growing militarism reflected in such developments as the abandonment of the SALT II treaty, the unleashing of the CIA, the development of the MX missile, and increased military spending."

The group is planning a march on the Boston campaign headquarters of Republican presidential candidate George Bush and of President Carter for later this month.