Rubin Carter's letter came two years ago on onionskin paper, in double-space typing and with important words and phrases underlined. Not a word misspelled. Not one eraser smudge. There was an address on the flap of the envelope: the Hurricane writing from Trenton State Prison in New Jersey.

A separate sheet of drawing paper showed a sketch of a redesigned boxing ring with its altered dimensions detailed in gothic script. Some of the letters ending words that ended sentences had tails that whipped into the margin, and the ink was indigo blue, the kind you get from fountain pens. Angelo Dundee looked it over a couple or three times before giving it to his secretary to put on file.

"He's my best friend," Dundee said, sitting in his office the other day in Miami. "They put him in prison for life for supposedly killing some people with a gun. My best friend, the Hurricane. And he's got an idea."

Dundee, who trained champion boxers such as Muhammad Ali and Sugar Ray Leonard, had appeared on national television a week before the letter came, and had talked about the death of Duk Koo Kim, a big-hearted South Korean lightweight who died as a result of blows received in a title bout against Ray (Boom Boom) Mancini in 1982. One of Dundee's friends said, "It seems every time some poor bleeding heart catches a glimpse of blood on a bully's face, they put old Ang on the tube and let him explain what it all means."

Earlier this month, the American Medical Association met in Hawaii and adopted a resolution encouraging "the elimination of both amateur and professional boxing, a sport in which the primary object is to inflict injury." It also resolved to "assist state medical societies to work with their state legislators to enact a law to eliminate boxing in their jurisdiction."

That was the AMA's most recent effort to abolish the sport its president, Dr. Joseph F. Boyle, once called "an exhibition designed to titillate people who find it glamorous watching macho men punch each other in the face."

And so the debate on the banning of boxing rages on, even as the sport's tevision ratings remain high, even after the American public became enchanted with the U.S. Olympic boxers, even after Thomas Hearns and Marvelous Marvin Hagler have signed for a fight that will bring each man an estimated $5 million when they meet this spring.

"I know that AMA," Dundee said. "I know what they're all about. Every six months, they have a convention. Don't you know they have to have a reason to have a convention, and in a classy resort like Hawaii. So what're they gonna do? They're gonna ban boxing. You think anybody'll pay attention to the AMA if they ban croquet or cricket?

"Hell, no. They pick on us at the peak of our popularity. Things are going smoothly for us now. But when something happens, like a death, we have to take a long look. When that Korean died, why didn't we study what happened? Why didn't a bunch of doctors look into the training techniques in Korea? Why? Because Korea's like a mystique. Like the Muslim religion was when it first came out with Muhammad. It scares you. What is it? I thought a Muslim was a piece of cloth."

Dundee took exception to the AMA's description of boxing; the fight game is, by his understanding, as scientific as it is athletic, and what does it mean when a neurosurgeon asks questions like, "What factors contribute to this continued public spectacle of brutality, and the literal sacrifice of minority youth for the profit and delectation of self-styled sportsmen?"

"Baloney!" Dundee said. "You go out there and whip each other and see who's the best man, that's all. Nobody's out to maim nobody. You're out there trying to score points. Trying to impress the judges and win. Who wants to get hurt?"

Dundee keeps a doodle sheet in a little black book under a heap of KO and Ring magazines on his desk. On it, he lists a number of safeguards he thinks "could prevent a tragedy or two or three." The graphic in Hurricane Carter's letter completes the list, and Dundee likes to show it off when someone asks for ways to make boxing safer.

The preamble to his private constitution goes like this: "It's a tragedy when someone doesn't make worthwhile out of his life. Teach a young man the art of self-defense and let him take out his inhibitions in a gym, and you'll have a better American citizen. Know what I mean?"

Hurricane Carter once had been a middleweight contender, but he was twice tried and convicted of the shooting deaths of three people at an all-night restaurant in Paterson, N.J. Bob Dylan, the balladeer, wrote a song about Carter's nine-year fight to beat the murder conviction, and even staged a Madison Square Garden benefit concert called "The Night of the Hurricane."

" . . . the back of the neck striking lower strand of ropes, coupled with the velocity of the fall itself, delivers a 'whiplash effect' directly to the nexus or nerve impulses at the bases of the skull, causing brain trauma and producing blood clots, which ultimately could bring about the death of a fighter . . . "

Carter wrote that in his letter to Dundee and suggested locating the lowest strand "six inches to the outside of a perpendicular line dropped from the upper strand." Dundee liked the idea. But a rope could only complete the damage begun by a fist. Dundee thinks gloves with contained or safety thumbs -- not thumbless or open-thumb gloves -- should be mandatory equipment to prevent eye gouging.

On top of that, Dundee contends every fighter should wear a mouthpiece made by a dentist and have an oral examination to determine whether his wisdom teeth should be removed. "Remove the teeth and the jawbone has a chance to grow," he said. "It's not the force of the blow that does a guy in, it's the condition of the jaw."

When Muhammad Ali announced his withdrawal from boxing on Dec. 12, 1981, he said, "I don't want to be one of them old fighters with a flat nose saying 'duh-duh-duh' before a fight." Less than three years later, Ali was diagnosed as suffering from "Parkinsonism," or minor symptoms of Parkinson's disease.

That day, speaking to a crowd of journalists, his voice was slow and slurred, as if his mouth were stuffed with cotton. He said then, "I've been punched a lot of times," but added that he did not regret fighting "because of the good it allowed me to bring to the world."

A team of physicians headed by Dr. Ira R. Casson of New York examined 18 former and active boxers and published its results in the May 25 issue of the Journal of the American Medical Association. The boxers underwent neurological examinations, EEG tests, computed tomographic scans of the brain and neuropsychological testing. Eighty-seven percent of the pro boxers with a substantial number of bouts had definite evidence of brain damage. All the boxers had abnormal results on at least one of the neuropsychological tests.

"One fact remains that must continue to be examined," Dr. Maurice W. Van Allen said. "A severe blow to the head damages the brain. Boxing, stated simply, is a disgusting spectacle. One can be broadminded about the human condition, and it's still sickening, especially from a medical point of view. How many physicians' sons are in the boxing profession? I know of none. Promoters take advantage almost exclusively of minorities."

Dr. Sam Sherman, a former chairman of the judicial council for the AMA, said he thinks the call for a ban is "a result of a great deal of emotion. The AMA represents doctors traditionally trained to save lives, but in my estimation, they used the overkill approach this time out. I do feel they acted responsibly, although somewhat drastically. You just d3308a national commission with standard rules in every state and region. Different rules from region to region is a problem. A 15-round bout, for example, is much too long, yet some commissions allow them to go on. I think congress would have to enact a commission to govern the sport, or some other such body with legislative power."

Casson agrees. "I don't think a ban is the answer," he said. "If you ban it, it goes underground or out of the country and there will be no controls. I think it will get worse. From a philosophical and a practical point of view, I don't think it's going to work."

Sherman was the first physician in the state of California licensed to work a corner. He worked with Carl (Bobo) Olson, a former middleweight champion, and advised him not to fight Archie Moore, then the light heavyweight champion, on June 22, 1955.

"Bobo violated a cardinal rule," Sherman said. "He didn't stay in his own class. Greed got in the way of good sense. In the third round, Moore cold-cocked him and put him on the canvas. After that, Bobo wasn't worth a damn as a fighter. It ended his career," although Olson bounced around 11 more years before retiring.

Many types of injuries can be inflicted in the ring. Brain damage occurs when a blow, striking the skull, causes the brain to move inside the head at a speed different from the skull. Cells snap and tear and small blood vessels break and produce small hemorrhages. Also, a massive accumulation of blood, or acute subdural hematoma, can fill the space between the unyielding skull and the mass of tissue of the brain. The pressure squeezes the very life out of the fighter, as it did in the case of Duk Koo Kim.

"See," Sonny Liston, a former heavyweight champion, once said, "all the brains are in a sort of cup and after you get hit a few times it shakes them out of that cup. When they give you smelling salts, it pulls them back into the cup. It's when the brains get shook up and run together that you get punch-drunk."

Most fighters attempt to justify the risks by comparing their work to that of hockey and football players. Elvis Yero, a senior national amateur champion in the 139-pound class, is 19 and a native of Cuba who became a U.S. citizen on Sept. 17, 1984, five days before the preliminary tournament for the title began. He fought 10 fights in less than 20 days to become the U.S. Amateur Boxing Federation champion, an odyssey that "wasn't tough, really. I didn't get a bruise." He says he would have fought every day and twice a day if he had to.

Dundee often reminds him, "Five of the Olympic gold medal winners got $100,000 for their pro debut in 1984. You'll win the gold in '88 and get double that."

But Elvis Yero says he's not "financially fit." His father Celestino was a professor of English in Cuba for 19 years before leaving his home in 1968 and settling in Miami Beach. First, the old man worked for the Economy Packing Co., feeding cattle. He was as tough as an old scar, and he raised his son tough, too. "I have never seen my dear son Elvis bleeding," Celestino once told a stranger. "But if I did, I would understand it. I have bled some myself."

"My father hurt his shoulder at work," Elvis Yero said. "He applied for compensation, but the check from the government usually gets in too late to pay the rent. I know if I turn pro we'll be able to pay the bills. I'm tempted. It's hard to go on just making it and fighting for medals and trophies and not money. I hope one day to be rich."

Reiner Hartmann, the West German heavyweight champion, is one of the most promising members of Dundee's stable. He works out at Miami's Allen Park Gym, throwing punches at shadows, slapping speed bags that ring like music. Because he makes so little money as a professional, he works at a Mercedes-Benz dealership, converting European cars to U.S. standards.

"When you're an athlete and special in the way God made you," Hartmann said, "you take your opportunities. I have a talent. I've been in boxing 10 years and came here to learn how to fight better. If they took boxing away from me, it would be like rewarding me with a piece of cake, then taking it away."

Kenny Baysmore, a promising Washington fighter who trains at Round One Gym in Hyattsville, said he's been in bouts where he "hurt the guy pretty badly. I've been stung myself, too. But it's not lasting. You always recover, or you think you do. When I see what's happened to Muhammad Ali, it affects me from a sympathetic point of view. But he just hung around too long. You have to know when to get out. I see myself fighting for six more years. Hopefully, no more. I won't let myself go out punch-drunk."

In a 1983 editorial in the Journal, Dr. George D. Lundgerg, the editor, concludes his remarks this way: "Boxing seems to me to be less sport than is cockfighting; boxing is an obscenity. Uncivilized man may have been bloodthirsty. Boxing, as a throwback to uncivilized man, should not be sanctioned by any civilized society."

Celestino Yero, who once roped wild bulls in a Cuban rodeo and came away with a half-moon scar under his left knee, often tells his son, "You must always keep moving, my dear Yero. Always keep moving."