BATTLE CREEK, MICH. -- On a typical afternoon at the turn of the century, John Harvey Kellogg -- physician, cereal visionary and founder of the modern health movement -- could be found in his study at the Battle Creek Sanitarium, bending over to administer his fifth enema of the day to himself.

It was apparently one of his most treasured rituals, given his lifelong emphasis on colonic purity. Kellogg's Sanitarium, founded in 1876, was the first institution of its kind dedicated to the pursuit of good health through a series of revolutionary treatments. He evangelized the fat, the sick and the tired, putting them through rigorous exercise to music (a century before Jane Fonda); feeding them from calorie-counted vegetarian menus; bunking them in beds attached to elaborate funnels that pumped in fresh air; and tending their bowels with ardor.

These images of the doctor's world -- with an emphasis on the scatological -- are portrayed with quirky affection in "The Road to Wellville," starring Anthony Hopkins as Kellogg. "Wellville," which opens Friday, shows Kellogg preaching his code for healthy living, a set of nostrums ranging from the inspired to the absurd, amid a host of Gilded Age neurotics, eccentrics and entrepreneurs eager to latch on to the health bandwagon.

But the depiction of Kellogg, who also invented peanut butter and the electric blanket, is causing angst among his followers. In Battle Creek, where he is still a local hero, Kellogg's Co. -- founded by his younger brother -- has completely disassociated itself from the film, and residents are concerned the good doctor's memory will be besmirched.

Their anxiety is not likely to be calmed by images of the doctor prescribing a 15-gallon yogurt enema to a young male guest, or his constant references to the perils of the colon. "My own stools, sir, are gigantic, and have no more odor than a hot biscuit," the doctor lectures a perplexed patient in the film.

"There is concern about what kind of film would come out of a book that is fictional but based on a real person," said Marlene Steele, the historian at Battle Creek's public library. "Wellville" is based on a novelized treatment of Kellogg's life by a master of dark humor, T. Coraghessan Boyle. "People are excited," Steele allowed, "but they're also worried maybe it will put Battle Creek into a bad light, and not represent a true picture."

But Alan Parker, who directed the film and wrote the screenplay from Boyle's book, insists that the hero has been shown in a positive light. "I read almost everything I could about him, and the dialogue is based pretty obviously on most of the things he said," Parker asserted. "He was a very autocratic figure, that's for sure. He was absolutely sure he was right about everything. Yet we show him in a good light -- albeit eccentric."

Hopkins's performance, the director said, is "much less gruff than Kellogg is in the book, and he comes across as more benign in the film. It's meant to be an outrageous comedy."

The film also reopens a bitter debate cutting to the very center of the nation's breakfast tables: Who invented the cornflake?

In his heyday, John Harvey Kellogg -- author of more than 50 books including "The Crippled Colon" and "The Disposal of Slops and Garbage" -- was the toast of the rich and famous. Visitors to "the San," as his sanitarium was called, included Eleanor and Teddy Roosevelt, George Bernard Shaw, John D. Rockefeller, Henry Ford and Johnny Weissmuller, the Olympic swimmer and movie Tarzan.

The first sign that greeted them at the gates of the elegant spa was "No Smoking on the Grounds." (A senator once visited the place and announced he was ready to give up smoking; Kellogg lamented in a health magazine in 1908 that the promise came too late. "He took a solemn pledge never to smoke again, and he has not; but he has lost his political position, and I believe he might have kept it had he stopped smoking before.")

Kellogg also preached against alcohol, meat ("a tide of gore") and sex ("the sewer drain of a healthy body"). He apparently did not indulge in any of these unhealthy appetites throughout his life -- the 42 children in his care were all adopted.

It all began with a vision. In the 1850s, Ellen White, a senior figure in Battle Creek's Seventh Day Adventist Church, announced that God had appeared to her and spoken of the virtues of healthy diet and hydrotherapy. The Lord gave her step-by-step instructions on how to buy land and set up a water cure.

The task of directing this inspired institution fell on the shoulders of John Harvey Kellogg, whose medical training was sponsored by White and who invented the word "sanitarium." The San prospered under his leadership -- but a feud broke out when White, who continued to receive divine instructions, claimed that Kellogg's expansions did not coincide with her visions.

The San flourished despite the rift. At its busiest, near the dawn of this century, its cosmopolitan clientele paid $6 a week for a room and $10 more for treatments. Among the most common ailments Kellogg treated was something he called "the neurasthenic condition." Also known as "nervous prostration" or "auto-intoxication," this was a 19th-century version of stress.

One of the most popular treatments was "diversion from morbid ideas and introspection" through doses of fresh air, sleep and "bottled sunlight." Intense electric lights -- described as "resuscitated sunlight of 10,000 candle power" -- were aimed at patients, who wore protective glasses. Neurasthenic patients were massaged, bathed in mud and stretched on special tables. A Dr. Giesel appeared at the San to lecture on the "evils wrought by corsets and high heels."

As the San's reputation spread, visitors poured through its doors -- 700 every week -- and the Battle Creek Idea, a weekly magazine promoting San treatments, was circulated around the world. In 1901, Leo Tolstoy Jr. wrote to the magazine on behalf of his father, the Russian nobleman and author of "War and Peace." Count Tolstoy loved its vegetarian diet, his son reported.

Kellogg was an international star. "We all knew him in Battle Creek, and he never dressed in anything but white, and he had a white goatee," said Robert Sharpe, aged 80, whose mother worked for Kellogg at the San. "He had an electric car with pink flowers on the doors. He let all the children use his swimming pool, which was quite something."

Yet it was not the Sanitarium -- or his regime of Gastric Correctness, or his stern loathing of masturbation, or his white outfits, worn to perfect his body's interaction with solar rays -- that made the Kellogg name immortal. Rather, as Hopkins says in the opening scene of the new film: "The cornflake is my gift to the world."

The facts have been lost in the mists of legend, obscured by a cloud of opposing theories and claims regarding the evolution of the tasty, lucrative morsel. Among those claiming some credit for the cornflake industry was Ellen White -- No. 35 on her list of godly visions dealt with running a cereal factory.

But according to the Battle Creek Historical Society, one general theme runs through all cornflake theories: John Harvey was in the kitchen at the San one day in 1894, along with his wife, Ella, and his younger brother, Will. The devoted vegetarians were experimenting with wheat products to serve their guests. A portion of wheat bran was rolled out and put over to one side and forgotten.

When they returned, the bran was stale. On a whim, they decided to force the grain through a set of rollers -- and it broke off into perfect individual flakes. When baked, the flakes tasted crisp and light. Corn tasted even better -- and the cornflake was born.

"All the stories involved all three of them," said Mary Butler, archivist for the historical society. "The wife was quite an important lady who hasn't had all the credit she deserves, but we're working on it."

It was Will, the younger and less flamboyant of the brothers, who recognized the potential of their invention. In 1906 he set up a cereal company, after arguing with his brother over the $50,000 cost of the factory. In 1922 the company was christened Kellogg's.

The cereal's success quickly attracted competitors to Battle Creek, which became known as the Cereal Bowl of the World. But Will outdid them all with his aggressive advertising, and each box carried his signature to show it was authentic.

Soon, the younger Kellogg's star eclipsed John Harvey's -- after all, his name was on breakfast tables across the country and, eventually, around the world. Another feud broke out.

John Harvey sued Will. Will sued John Harvey. For years, they hardly spoke to one another.

"They were different kinds of people with different purposes," said Butler of the historical society. "Will added ingredients, sugar and malt, that John Harvey didn't agree with."

In 1943, John Harvey -- who kept plugging (and unplugging) at the San, which he ran as a nonprofit institution -- sent a conciliatory note to Will. But later that year, the old doctor was dead at the age of 91.

Today, the San is testimony to the long arm of Washington: It is used for federal offices.

Though his name was overshadowed, John Harvey Kellogg's legacy has endured: With the possible exception of his enthusiasm for bowel purgation, most of his treatments are still popular. Little has changed in the world of health spas he helped to create -- aside from the prices.

Each year the rich and famous and auto-intoxicated of the '90s pour into the health spas of such villages as Palm Springs. For example, at Two Bunch Palms -- a favorite of Julia Roberts, Madonna, Robin Williams and Meryl Streep, where a room costs up to $400 a night and treatments are up to $400 a day -- the nervously prostrate enjoy mud baths, steam rinses, stretching treatments and massages. The restaurant menu praises clear air, warm water and bright sun -- a virtual homage to John Harvey Kellogg.

So perhaps it's appropriate this film should come along just now. No matter what the people of his hometown might dread, Dr. Kellogg has earned his place in memory: The second-greatest flake from Battle Creek.