Debi Thomas, pre-med student and world champion ice skater, has left the chemistry building without spilling anything toxic. Aboard a 10-speed, dark Ray-Bans fixed in place, she hurtles through the rarefied academic country club of Stanford University, in imminent danger of piling into a palm tree or Linus Pauling.

Nobels and Pulitzers and laureates and emeriti -- whoops, there goes writer Wallace Stegner -- are so many ribbons and papers when there is a medal-bedecked world champion on campus. University president Donald Kennedy personally gave her a letter jacket. University provost Jim Rosse wandered out to the quandrangle to ask, "Is she here?" English professor Gregson Davis praised her in the words of the lyric poet Pindar.

This is unprecedented attention for a freshman who still has braces on her teeth and who was going to major in the first thing she came to, because she couldn't find the right building. But Thomas is clearly a rarity, for last month she took her medical microbiology studies on the road and won the skating gold medal at the World Championships in Geneva, defeating Katarina Witt, the two-time titlist. She is the first black ever to accomplish anything of significance in skating.

For two years a relative unknown behind Witt and 1985 national champion Tiffany Chin, Thomas has since won the gold medal in five straight competitions, including the national and world titles, to become one of this country's great hopes for the 1988 Olympics in Calgary. Her victories are extraordinary, because the aspiring orthopedic surgeon has been triple-salchowing between final exams in calculus and Western Civ to become the first skater since U.S. champion Tenley Albright, Radcliffe class of '58, to attend college and skate in world class competition at the same time.

"Let's put it this way," said freshman bunkmate Kaija Lewis. "She's not your ordinary roommate."

The phone rings for the 499th time in Thomas' room. The world champion figure skater answers. It is a reporter.

"Is Debi Thomas there?"

"She's at class," Thomas says. "This is her roommate."

This is not the girl who two months ago was skating effortlessly and classically to Verdi. Nor the elegant, charming young woman who conducted an interview in French, and who is teaching herself Russian for fun. This is a 19-year-old who put on 15 pounds from mystery meat and mashed potatoes, then had to lose it on a crash diet of soup before a skating competition. An easy laugher who likes her Def Leopard ear-splitting, who is not adverse to water fights, who can shoot a spoonful of peas across the room.

She has abandoned her usual skating costume of black spandex trimmed in lavender and periwinkle blue, with sparkling rhinestones and silver studs, for more appropriate collegiate wear -- worn jeans, high-top sneakers, T-shirt, letter jacket and impenetrable shades. She is sloppily at home in this resort of a place.

"Everything is so disgustingly fun," she said. "I'm the world champion, and I'm at school here, and it's like summer camp. If I could just get the chemistry done."

The feature attraction of her room is a mass of papers, notes, records and tapes, many of which appear to have been gnawed. It is not uncommon to see camera crews visiting the room, or following her to lunch. When she is competing, it is a chaotic communications center where roomates Nicole Holzapfel and Lewis issue bulletins on her intercontinental progress to a stream of visitors. When Thomas won the nationals, the dormitory erupted in a celebration that could be heard on Campus Drive.

"By the time she won the worlds, we sort of expected her to," Lewis said. "We were so used to her winning."

Coach Alex McGowan, Thomas, and her mother Janice are discussing a variety of subjects: her future, her fan mail, her finances. "You know, some poor skater might appreciate . . . " McGowan said, then stopped. "But of course," he said, "you're one of those poor skaters."

The Thomas household has been in a state of financial struggle since the day 5-year-old Debi was taken to an ice show, pointed to the rink and said firmly, "I can do that."

She grew up in a middle-class neighborhood in San Jose. Her parents, both in the computer industry, are divorced. She was raised primarily by Janice, a programmer analyst who split her time between a full-time job, raising Debi and brother Rick, and acquiring a masters in business by night.

Nine months of training runs about $25,000 between rink fees and McGowan's fee. Skates cost $450, and the blades another $150. McKinley Thomas, Debi's father, pays the rink fees, and her grandparents contribute toward her skating clothing and competition expenses. She receives financial aid at Stanford.

"She did it on second- and third-hand skates," Janice said. "The biggest obstacle was money. You could fill a book with all the crazy things we had to do to make it work."

Thomas' work ethic is an inherited trait. Janice, the daughter of a veterinarian and social worker from Wichita, Kan., received her undergraduate degree in physics from the University of Kansas at the same time she was raising Rick, now 27. It is as much through Janice's insistence as Debi's that she skates and studies at the same time.

"I can remember taking the baby to atomic physics class," Janice said. "Then with Debi I was working full time and going to grad school at night. I guess that's where she got it. She's used to seeing it. I was never trying to develop a champion skater. I just believe in developing bodies and minds."

The question most frequently asked of Debi is whether she has encountered racism or sexism in skating. "Never," is her standard reply. Janice, who encountered much of both, saw to that, too.

"I'd had enough of it in my field, being female and black. I worked hard to give her a good self-image, so she would never feel she had to prove herself to other people. Any time I saw a sign of sexism or racism, I made sure she never thought along those lines."

Mired in work during fall term, Thomas tore up her entry form to the national championships and stopped skating for two months. McGowan and her mother protested and persuaded her to at least keep the pieces. They gradually talked her into training again, and Thomas taped the form back together. Janice ironed it before she mailed it off.

Debi Thomas has this thing about lights. When they go on, so does she.

She is an impressive sight on the ice, for at 5 feet 6 she is statuesque for a skater. She differs from her closest competition in that respect; Chin, the national bronze medalist, is fluttery and workmanlike; Caryn Kadavy, the national silver medalist, is willowy and elegant; Witt is regal and beautiful. Thomas by contrast is raw and charismatic, and when the adrenaline is going through her like rocket fuel, she is nothing short of magnetic.

"I'm a ham," she said. It's a necessary asset, because she is an incorrigible risk-taker who frequently seems on the brink of disaster. In five weeks of preparing for the February nationals, she did not once complete her long program without a mistake and spent most of the time studying for midterms.

"She was a physical wreck," McGowan said, and he told Thomas as much.

"I warned you," he said. "I told you, you can't go to school and train at the same time and expect to win."

"Watch me," she said.

When Feb. 8 came, she was a nervous wreck as well, and fell twice warming up on her triple salchow. Trailing Kadavy after the short program, she needed to land all five triples in her routine to win the gold. She gave one of the most stunning performances of her life to win. "She's a fighter," McGowan said.

At the world championships, Thomas again had exams to contend with, this time finals. Despite completing a three-hour calculus test in her hotel room, she was in second place after the compulsories, and held the lead after the short program when Witt suffered an embarrassing fall. She needed only to get through the long program without a serious mistake, which she did, omitting a fifth triple jump. But she felt compelled to add an improvised combination jump, against McGowan's orders. She carried it off and upset Witt.

"Doing things the hard way," she said. "That's my middle name."

Her willfulness in disobeying McGowan's directions has made for a strange working relationship. They communicate in inverted form: McGowan, equally obstinate, tells her the opposite of what he wants her to do, secure in the knowledge she will argue. The method is inarguably successful.

One issue they have never resolved, however, is school. For years McGowan, a native of Scotland who leans toward the conservative as a coach, has pleaded with Debi and Janice to postpone her studies and train full-time. Since Thomas entered Stanford last fall, there has been more than the usual amount of friction between coach and skater.

"He's always right," Thomas said, irritably. "He'll never be convinced. Even now, after winning the world championship, he doesn't think we went about it the right way. To tell you the truth, I think he made it more difficult than it had to be; he added pressure. But maybe that's why it works. He says, 'You can't do it,' and I say, 'Watch me.' "

McGowan calls her victories at the nationals and world championships flat miracles.

"I wouldn't say we did it the right way because of the stress on both of us," he said. "There was more on her, of course. But it was an enormous struggle. The odds are always against her."

Despite the tension, she has remained loyal to McGowan when she might well have found a more notable coach. The part owner of the Redwood City rink where Thomas trains, McGowan has never before had a successful protege. In comparison, Chin trains with Don Laws, Scott Hamilton's former coach, and Kadavy, a gorgeous stylist from Erie, Pa., who may well challenge Thomas next year, is a protege of Carlo Fassi, who produced Dorothy Hamill.

"After the nationals, I really felt like king of the hill," McGowan said. "Then I thought, 'Well, I'm not really king of the hill until we win the worlds.' After that, I really thought we had done it. Between the stresses and strains, we produced a world champion. So I'm happy."

"You have to understand," said Ruby Mason, Thomas' academic adviser, "there are tons of these kinds of people at Stanford. She's a typical solid Stanford student; it's just that the nature of what she does is a little different."

Thomas takes considerable sorting out. She carries a basic freshman pre-med load of English, calculus, chemistry and western culture, but life is complicated by her lengthy practice sessions. She trains at McGowan's Redwood City ice rink from 1:15 to 7:45 p.m. every day. Mondays and Wednesdays are particularly bad, with classes all morning in addition to the practice.

"Suicide days," she calls them.

The first publicity photos of Thomas when she returned from the world championships were unusable. Pouches and shadows decorated her eyes, which generally looked as if they had been punched.

"For weeks she was getting no more than two hours sleep a night," Holzapfel said. "If she got into bed before morning we were amazed. 'Oh my God,' we'd say. 'Debi's in bed.' "

Thomas has had occasional bouts of depression severe enough to make her briefly consider quitting both skating and school. She does admit that she will have to take the winter term off in 1988, which will be her junior year, when she will compete in the world championships and Olympics.

"I have no intention of quitting, because it's what I want to do," she said. "It's not as if I'm always working. It's not work, because it's what I like."

Thomas had just completed her superb long program to defeat Chin and Kadavy and win the gold medal at the nationals.

"What are your immediate plans?" a reporter asked.

"Yes, I'd like to know that, too," McGowan said.

"To read Dante's 'Divine Comedy,' " she said.