Sheila Joyce washes her hands anywhere from six to 12 times in the course of her working day. She isn't a doctor, or a dental hygienist, or a nurse, and as far as can be ascertained she has no trouble in the Lady Macbeth area. She's a bank teller, and her fingers get smudged from handling stacks of filthy lucre.

"Ink rubs right off new money," Joyce said. "When I first started working in a bank I noticed my fingers got real dirty real quick, and there was something in the ink that made my fingers start breaking open, and so it didn't take me long to get in the habit of frequent washing." She has been a bank teller for eight years now, the last six of them in the Shepherd Park branch of the National Bank of Washington on upper Georgia Avenue.

Another thing Sheila Joyce has noticed in the last eight years is that she gets far fewer colds and flu than she did before, and a lot fewer than her friends and colleagues who haven't been washing their hands as frequently.

In 20th-century America, the old saw "living from hand to mouth" can be reworked as "dying from hand to mouth" for maybe 80,000 people a year, estimates the federal Centers for Disease Control in Atlanta.

This is because bacteria and viruses, including the strains of virus believed to be responsible for the common cold, are transmitted largely by hand contact from person to person -- not by inhalation, as had been believed down through the ages.

More than 20,000 deaths a year result directly from infections acquired in a hospital -- called nosocomial infections -- the CDC reports. These infections contribute indirectly to another 60,000 deaths, the CDC says, and present to the bill-paying public an annual cost of $2.5 billion for treatment, says the Department of Health and Human Services.

One third of these infections are preventable, estimates the CDC, and the people who look at these things say the best way of preventing them is by washing your hands.

"A 30-second handwashing can rid your skin of 90 percent of the particles carrying viruses," said Dr. Lawrence D'Angelo, who heads the department of adolescent and young adult medicine at Children's Hospital and is also chairman of its Infection Control Committee. "If people are scrupulous about washing their hands, it can cut the risk of catching colds, for instance, dramatically."

Hand-washing, he says, breaks the cycle of the cold virus transmission. Repopulation of the hands with viruses and bacteria begins immediately, with the first covered sneeze or the first touch of a doorknob, but the hands can be washed again.

We're not just talking about colds here, though. Hand-washing can also protect against the kind of infections that can kill, particularly in hospitals, where some health care professionals may move from patient to patient without taking the time or mild inconvenience of washing their hands.

"I wash my hands 12 to 18 times during a working day," D'Angelo said. "That's before and after seeing each patient, and sometimes in between. That's a lot, and it's irritating and tough and it's so easy to skip, and eventually it gets to hurt, and I use an awful lot of hand cream, but it simply has to be done. Even in a hospital environment people tend to go around it."

At Children's Hospital here, a lot of doctors are getting a new message about their hands, and their egos. One doctor, who remains unidentified, emerged with a beet-red face from the room of a little girl, spouting:

"She said I couldn't touch her until I washed my hands! She said I should go wash my hands! I can't believe this!"

That young patient was following the advice of Children's Hospital's new T. Bear campaign, a nationwide effort launched by HHS to help control the spread of controllable infection in hospitals.

Under the program patients are asked to demand that they get a germ-free hand on their fevered brows. The kids in the Hematology-Oncology unit at Children's Hospital, for instance, were provided last week with 16-inch stuffed bears, all named T. Bear, to hug and to remind them to ask of their healers that which is next to godliness: simple cleanliness. Members of the Pringe George's County Zonta Club raised $500 through an art show to buy enough T. Bears for every kid admitted to that unit in the next two years, according to Zontian Dr. Agnes Donahue, a pediatric dentist.

The idea is to get doctors and nurses back to basics, the simple cleanliness (leading to the asepsis of the ideal modern hospital) that makes it more difficult to spread one or more infections from patient to patient by a white-jacketed Typhoid Mary.

And the T. Bear campaign (the theme is "Handwashing Prevents Infection . . . It Really Does") is being taken to the day-care centers as well as the hospitals for two reasons: the people who work at the centers may not have had grandmas who insisted they wash their hands, and it is a prime place to teach small human beings the rudiments of personal hygiene.

The whole business goes back to soap and water, and your grandma knew all about that. When things are clean you don't get sick so often.

Soap-making, boiling animal (and sometimes vegetable) fat and caustic alkali (lye and wood ashes) together, the way Grandma did it, and then skimming off the dross, seems to have predated the Romans and was described by Pliny (Pliny the Clean). The art moved across Europe from Rome in the 12th and 13th centuries and remained a cottage project until the 19th century, when, under the auspices of the Industrial Revolution, a way was found to make large amounts of soap fast. The soap we have now is essentially the soap they had then: a chemical compound resulting from the interaction of fatty oils and fats with alkali, possessing the properties of sudsing, detergency, surface tension lowering, wetting and emulsifying power.

There is some difference of opinion about whether soap is a germicide in itself. The most recent textbook for nurses on the subject ("Introduction to Asepsis," by Marie M. Seedor) states flatly that the sudsing action in handwashing is all that counts, the mechanical flushing away of the germs.

Your old reliable Encyclopaedia Britannica will tell you flatly that "Soap itself has germicidal power against some organisms, and many of the cationic synthetic detergents are strongly germicidal."

Dr. D'Angelo, who grits his teeth and damns the microbes and scrubs full steam ahead, tells us that soap does have germicidal and viricidal action, but not against all bacteria and viruses.

Grandma said she didn't care, she wanted it clean.