Muhammad Ali's personal physician said yesterday that the former heavyweight champion "could have died of heat stroke" on Thursday night in the 115-degree desert heat of Las Vegas had he not received emergency treatment when his bout with champion Larry Holmes was stopped after 10 rounds.

"He became extremely dehydrated," Dr. Charles Williams of Chicago said on the telephone.

"He went into heat exhaustion, almost a heat stupor. He was headed toward a heat stroke, because he had stopped sweating. It was a very ominous sign.

"That was what happened to those people down South who died during the heat wave this summer."

"I treated Ali right after his bout. He seemed a bit stupid and I wasn't sure whether it was from a concusion of the head, whether it was the beginning of a heat stroke or whether he was becoming delirious. The victim often suffers a change of personality.

"He became extremely sleepy and rolled over on a couch in the trailer used as a dressing room, as if he were going into a coma. I gave him a stimulant and a small amount of tranquilizer, and he came out of it. I gave him some Tylenol for his pain and to bring his temperature down.

"We didn't want to bring an ambulance there in front of all his fans. He walked out of the trailer to his car, and then went to his hotel room. He seemed very alert and awake, in pretty good shape.

"He might have been on the verge of becoming delirious after the bout, because I remember that he was asked why he didn't throw punches at Holmes when there were openings and he said, 'Holmes seemed so far away.'

"I didn't like the way Ali looked on Friday afternoon. He told me he felt fine. But he wanted to know why he felt so weak during the fight. I recommended that he go to the University of California at Los Angeles Hospital for tests by Dr. Dennis Cope, whom I have talked to about Ali's case."

At a news conference at UCLA yesterday, Ali said an overdose of thyroid medicine made him physically unfit to fight Holmes. Doctors were reported as saying Ali suffered no residual damge from the fight and that he was given a clean bill of health.

Ali said he was taking six grains of Thyrolar a day, in two pills, although his doctor told him to take only one pill, because Ali thought the regular dose increased his vitality. His weight dropped from 254 to 217 1/2 in five months.

Before those reports yesterday, Williams, assistant professor at the Abraham Lincoln School of Medicine in Chicago, said he did not give the Thyrolar to lose weight, but to correct a hyperthyroid condition.

"My impression was that that (the hyperthyroid condition) was the reason Ali gained all that weight and suffered slurred speech while in retirement.

"I'm sure he was dehydrated. He was producing a markedly diminished urine output. He didn't drink enough water in training to keep up his urine output.

"Much of his bloated condition and thickness of speech then was due to his thyroid condition.

"I never really was satisfied with his condition before the Holmes fight. I wanted him to weigh about 225, but he continued to dehydrate. He wouldn't drink water or eat. He looked fine the day of the bout, but his mouth and skin tissue were too dry. He wasn't perfect, but was okay to fight.

"He didn't tell me till after the fight that he tried to run for 30 minutes three days before the bout, but couldn't. He complained constantly about the heat during the fight.

"I think we (Williams, Ali, and the rest of the entourage) goofed. I think his condition was correctable. I didn't emphasize enough that he drink more water. I expected this trouble because of his loss of weight. He can get over this and fight again. It can happen to anyone training in daily 100-degree heat."

Asked why Ali's condition was not observed at the prefight physical examinations -- a week before and a day before the fight -- Williams said, "When you are examined while calm and lying down it is different from when you have just finished fighting. Those examinations should be given after a boxer has had a stiff workout or has just finished running several miles.

Sig Rogich, chairman of the Nevada State Athletic Commission, said "I think the most pertinent fact is that Ali was down to 230 before he came to Nevada for training.

"I got a copy from the Mayo Clinic of the examinations Ali underwent there. It constituted a clean bill of all areas pertinent to the fight. I took it back for our commission physicians to study, including a neurosurgeon and a cardiovascular specialist.

"Ali lost only about 10 pounds after I saw him in Deer Lake. I can't believe the Mayo Clinic would jeopardize its standing with anything but a complete, true report. That is the Cadillac of health care. We have antidoping test after a fight in Nevada, a urinalysis. I think somebody wants Ali to fight Mike Weaver (World Boxing Association champion. Holmes is the World Boxing Council champion)."

Dr. Donald Romeo, Nevada commission physician, said on the phone from Las Vegas, "I was not aware of what was done about Ali using any thyroid drugs for a weight loss. My examinations a week before and a day before the fight showed no evidence of Ali being on thyroid medication. His cook was reported as working up the diet to lose weight."

Dundee said on the phone from Miami, "I don't know of anything given to Ali in camp. He never complained to me. He didn't even complain when he had a broken jaw (in losing a decision to Ken Norton)."