The State Senate refused today to reinstate Maryland's motorcycle helmet law as several lawmakers scoffed at safety studies purporting to show that helmets save lives and declared that basic freedoms were at stake.

The 24-to-23 vote to scuttle the proposal to require helmets came shortly after Gov. Harry Hughes remarked at a press conference that he had lobbied for the measure and confidently predicted its adoption.

Those supporting the attempt to restore the helmet law, which was in effect from 1968 to 1979, cited a study showing that there was a 50 percent increase in motorcycle fatalities in the year following the law's repeal. It also showed that 61 of the 95 persons who died in motorcycle accidents last year were not wearing helmets.

These figures were attacked by opponents of the law, who said they fail to take into account a recent large increase in motorcycling in the state, reflected by higher registration figures.

Several senators also advanced more basic arguments.

"We can't take away the right to be stupid," said Sen. Julian L. Lapides (D-Baltimore).

"How far can we intrude into the lives of the citizens of this state and this country?" asked Sen. Clarence M. Mitchell III (D-Baltimore). "Are you gonna say wear a helmet walking up the stairs? Or seat belts in the kitchen?"

The Senate action came on a vote to reconsider a roll call earlier this week in which the measure unexpectedly failed, also by a single vote.

The measure had widespread support from state health groups but was vigorously opposed by motorcyclists who showed up in large numbers during hearings to lobby against it. Nonetheless, the bill had been expected to pass the Senate and then face tough going in the House.

At his regular press conference today, two hours before the vote, Hughes told reporters, "We have been talking to people, and I think you'll see that the bill will pass today."

When it didn't, Hughes' press aide Gene Oishi said, "It was his impression we had the bill." Two senators who voted against it Tuesday supported it today, he noted, "and we assumed no defections. It's embarrassing, isn't it?"

Today's vote followed an hour-long debate during which lawmakers held aloft helmets as they expressed differing views. "This helmet saved the life of somebody I know," said Sen. Francis X. Kelly (D-Carroll-Baltimore County).

Sen. Peter Bozick (D-Prince George's), who fought for repeal two years ago, also had a helmet. He said it would narrow peripheral vision and cause a loss in hearing that could jeopardize the wearer's safety.

"I could produce evidence to show helmets or seat belts kill people," Bozick said. "Who wants to look at statistics? The main thing I'm interested in are rights . . . the basic right of an individual to do something unto himself?"

Robert E. Stroble (D-Baltimore County) raised another problem for helmet wearers, should the bill pass. "What do you do with it if you stop?" he said.

Mitchell, the Baltimore senator, sketched a picture of a suffering cyclist heading for Ocean City on a hot summer day. "Can you imagine," he asked, "it being 102 degrees, bumper to bumper going to Ocean City and you can't take off the helmet?"

After the vote, Sen. Sidney Kramer (D-Montgomery), said the bill's demise "translates into lost lives." He said he would bring the bill back for consideration next year.