The 64-year-old man with the Zero Mosiel face and thick, silver eyebrows sat on the edge of his hospital bed, fingering his green plastic identification bracelet and telling of the "pet food" he ate because he was poor, but not poor enough.

He had eaten the pet food, along with stale, brittle bread and rusty canned foods until it was more than his chunky 212 pound frame could stand. A diabetic with a heart disease, he had been taken to the hospital two weeks ago complaining of severe chest pains.

His doctors declared him well days earlier. Yet until yesterday he remained a patient of Prince Georges General Hospital, literally trapped in a $150-a-day semiprivate room by a society that has declared him too rich to be helped, but too poor to stay well.

Social agency after agency contacted by the hospital or the man's wife said no. Because the couple could have as much as $433.60 a month in income, they were too well off to qualify for public assistance, the agencies said.

But they were aalso too poor to buy the foods that the man's doctor said he must have to stay healthy. Troubled by the certain prospect that his patient would once again become ill if released, his doctor took what was a bold step: he refused to allow the hospital to release his patient.

For days, the hospital seemed baffled. "We're trying to pactch something together . . .," said Sandford Wilcox, a hospital official, on Thursday night. "But there are so many Catch 22s to his problem."

Yesterday, fewer than 12 hours after a reporter began making inquiries about the case, a solution appeared as the man's physician. Dr. Robert Dietz, put it: "All of a sudden, like manna from heaven."

A fraternal organization willing to give the couple $30 a week for the next three months surfaced. An unmaed donor offered a month's medicine. An apartment renting for $75 under their current $239 a month Forestville apartment was discovered and the heads of the various public agencies that had said no to the couple agreed to reconsider their request for funds.

"This is dynamite . . . just what they needed," said Dr. Dietz, a 43-year-old Hyattsville cardiologist, who had risked provoking the hospital's ire by refusing to discharge the man. "It happen somehow; how I just don't know."

A hospital spokesman said yesterday they could not recall of a similar action by a doctor nor could they recall of a case as perplexing as that of the 64-year-old man.

To Dietz, whose practice is "more on the affluent side," the dilemma his patient faced represented "a failure of our whole system." It is also illustrated what hospital social workers said is a commentary on how easily a family that is slightly above the government's officially proclaimed poverty line can become victims of the rapidly rising costs of food and a dwindling income.

The man, who pleads that his name not be used because of the embarrassment it might bring his wife who works at a part-time job for the District government, says he had no choce but to eat the pet food. "The doctor's got me on a diet I can't afford," he said Thursday afternoon as he said fully dressed on the bed of a hospital room, paid for by an insurance policy he has.

His pudgy face and steel blue eyes are etched by the worries of living off $483.60 a month in one of the nations most expensive metropolitan areas. "With lettuce at 69 cents a head and tomatoes at 69 cents a head . . ." he began.

His voice trailed off and then he mumbled about the cost of cottage cheese and tuna, which his doctor had also wanted him to eat. The man doesn't even know the prices for those items and it is probably just as well he said. He couldn't afford them either.

After paying his rent, making a $20 payment for car repairs, $40 for gas for his wife's car, about $75 for medicines, and utilities, there remained about $65 to $75 for a month's food, he said.That forced his wife to buy bulky starches - rice, beans and the like - along with the pet food, stale bread and out-of-date canned goods.

When the family's medical bills were so high that they could get food stamps, his wife secretly would pull the "pet food" label off old meat scrap bags in order to buy the meat with the stamps. (Pet food cannot be purchased with food stamps under government regulations.)

"They call it pet food and say it's not for human consumption," the wife said. "But it's old ground beef that I make into mea ltoaf and eat."

Because the man said they had no choice, he would eat the meat loaves, the stale breads, and old canned goods, knowing they were, as his wife said "poison to him."

"A healthy 18-year-odl could probably eat the dog food without any harm," said Dietz. For the old man, it was too much, pumping too many starches and too much sugars into his body, he said.

When he was admitted to the hospital, two weeks ago, his blood contained a dangerously high level of sugar. Under treatment and a planned diet, the hospital was able quickly to restore the man's health.

Dietz, however, was adamant that the hospital not release the man until he was certain that his financial troubles were resolved. "Under the circumstance I believed I could not authorize his release because he could easily end up back in their with a coronary," Dietz said.