Something went terribly awry yesterday in that ultimate bastion of refinement, the U.S. Senate, normally a place of tradition, decorum and courtesy.

Senators, who seldom address one another in terms other than "my esteemed colleague," broke into spirited name-calling at a hearing on a controversial anti-abortion bill. As if that weren't enough, a Democratic senator testifying against the bill decided to take over the hearings while the bill's Republican proponents were out of the room.

It all began when Sen. Bob Packwood (R-Ore.) accused anti-abortion senators of having a "Cotton Mather mentality" and of imposing it on the nation. (Later, some of this same language was to spill over on the Senate floor.)

Packwood, a longtime leader of pro-abortion forces in the Senate, accused anti-abortionists of taking a holier-than-thou attitude.

"God did not speak to any one of us and say, 'you are right and those who disagree with you are wrong,'" he said. "If any one of us thinks that God has ordained us to speak for Him, we are wrong. Worse, if we are in positions of power and believe we speak for God, we become dangerous."

Taken back, Sen. John P. East (R-N.C.), who was chairing the hearings, promptly pronounced this "rhetorical overkill" as unbecomming a senator. "I do not agree we are Cotton Mathers," he shot back. "I do not agree we are trying top impose some Ayatollah Khomeini morality on this country."

Before Packwood could reply, senators had to rush to the floor to vote on an unrelated matter. When East and other senators on the separation of powers subcommittee returned, after more than 30 minutes, they discovered that Sen. Daniel Patrick Moynihan (D-N.Y.) had grown so impatient that he had taken matters into his own hands and had continued the hearings.

Moynihan did so for about 10 minutes, skillfully making points with a number of House members testifying. Then, he announced, "Will you forgive me. I have to go vote, too. Perhaps one of you would like to take over."

"That would be a great privilege," replied Rep. Charles F. Dougherty (R-Pa.), adding that he thought that would be improper.

When East returned, he agreed. Obviously upset with Moynihan, the subcommittee chairman said the New York senator's actions were "out of the ordinary. But that colleague is out of the ordinary."

The hearings returned to normal after East sparred for a few minutes with Rep. Millicent Fenwick (R-N.J.), another opponent of the bill, who had sat bemusedly puffing on a small pipe as Moynihan took over the hearing.

Testifying in support of the bill, which would prohibit abortion by defining life as beginning at conception, were Rep. Romano L. Mazzoli (D-Ky.), Dougherty, Stephen H. Geleback, a Washington lawyer, and John Noonan Jr., a law professor at the University of California at Berkeley. Testifying against it were Laurence H. Tribe, a Harvard University law professor, and William Van Alstyne, a Duke University law professor.