Anyone who has ever experienced the power of Beethoven's Ninth Symphony -- or the polyphony of a Georgian folk song -- knows that music can influence a person's mood. Many musicians also believe it can affect a person's body. A drummer in New York City has been investigating whether music can have an impact on the heart - and now he has some members of the medical community listening.

For the last 40 years, Milford Graves, 63, has been touring the world, playing drums. In 1967, he was proclaimed the brightest new talent of the year by Down Beat magazine. He still performs, touring most recently in Sweden. But, for most part, Mr. Graves spends his time nowadays teaching jazz improvisation at Bennington College in Vermont and conducting research into the physiological effects of music.

"If somebody's heartbeat comes in like this," he says, beating a solid, regular rhythm on a drum in his studio, "that's tight, very tight. You don't want that." He changes to a more variable beat and praises its effects on the heart. "It's more than theory,' he says, "because it works with a lot of people. I see it. It works. That's the bottom line. No matter how we explain it, the critical findings are real good."

What Mr. Graves has found is that a normal -- or what some might call a regular -- heartbeat, is actually quite irregular, comprising all sorts of random contractions that, until recently, doctors could not hear because the frequencies were too low. But, in the basement of his house in Queens, New York, Milford Graves has devised a way of using computers to identify and record these frequencies.

"See, it's only recording the big ones and the small ones," he says, as he plays a traditional recording of a heartbeat on his computer. "But we want all of them in there. Now you do it like this," says Mr. Graves, striking a key that changes the frequencies of the beat so that numerous other beats can be heard in between the main ones.

Mr. Graves compares these beats to music -- specifically Cuban and Nigerian drum rhythms -- in an effort to understand them. He beats out a passionate and powerful Nigerian rhythm on a bha-tah drum. "And the Cubans, when you hear the Cubans play their bha-tah, they make like [this]," he says, changing the rhythm to something entirely different, but equally erratic. "That's all those beats in between there. They're smart."

Milford Graves calls Nigerian and Cuban drummers smart, because he says they figured out centuries ago that an external, irregular drumbeat can have a positive influence on the health of a listener. He says these drummers probably did not understand why their music had that impact -- but now, thanks to computer technology, we can. Mr. Graves says music can actually re-program hearts that are not beating as irregularly as they should. "You can send another stimulus, to counteract that [unhealthy beat] inside," he says. "So you set up this interplay, to try to get this [drumbeat] to overrule."

Milford Graves' research was persuasive enough to convince the Guggenheim Foundation to give him a grant to update his equipment and continue his studies. He has also attracted the attention of doctors such as Baruch Krauss, an emergency room physician who teaches pediatric medicine at Harvard Medical School. Dr. Krauss calls Mr. Graves a modern-day renaissance man, akin to Leonardo da Vinci. He says researchers at prestigious medical schools like Harvard have only begun to understand what Milford Graves was able to discover in his basement -- that a normal heartbeat is poly-rhythmic.

Dr. Krauss says that, although the medical community is not yet ready to start using music to treat patients, physicians do use electronic pacemakers to correct rapid heartbeats -- a principle that is quite similar. "So you take an external pacemaker," he says, "and you feed in stimulus to the heart, to increase the rhythm even further, which actually drops it back down to normal. That's not very different, in principal, from what Professor Graves is proposing."

Of course, implanting a pacemaker does involve minor surgery, which is a bit more invasive than the acupuncture needles Milford Graves uses to deliver his drum patterns to an individual's heart. That is why Baruch Krauss says Mr. Graves' ideas about music and the body deserve further exploration and more funding.