As I lay on my back, the first silver needle pricked the skin of my instep. The sensation was so slight it was as though I had brushed a filament of stereo speaker wire or touched the tip of a thorn. The needle was so fine and flexible that if not in the hands of an expert, it would have bent when meeting my skin rather than sticking. The next sets of needles went into my wrist, chest, abdomen and lower neck. I had been a pin cushion for 20 minutes before he at last applied his needles to the area I needed treated.

The tender spots in my lower back felt the final ten minutes of treatment from needles so fine that they never broke the skin. The finishing touch: he held a smoldering root, known as moxa, above the treated area to induce relaxation.

Unfortunately, my condition is chronic and will take a long series of treatments to recover fully. According to my acupuncturist, who has just returned from four years of study in China, the diagnosis is simple: my qi (pronounced key) was severely imbalanced. To regain health, he must restore me to an even qi.

Western medicine bases diagnoses on specific symptoms, but traditional acupuncture determines treatment by reading your qi, or energy flow. To test a patient's qi, an acupuncturist examines a patient's skin color (coffee drinkers are distinguishable from non-coffee drinkers), listens to his voice, samples his odor (diabetics smell sweeter than non-diabetics), and most important, the patient's pulse.

Adept acupuncturists can differentiate six separate pulses in each of your wrists, or a total of 12 distinct beats. Each of the 12 pulses corresponds to 12 meridians, or energy paths, that course through the body running from legs and arms to head. These 12 meridiens in turn, correspond to 12 organs.

The pulse quality is critical, and is rated either fast or slow, weak or strong, difficult to locate or "floating." Different acupuncture systems categorize the pulse types by more than 24 different qualities.

Pulse determines therapy. Western diagnoses such as stomach ulcers or colds have no translation into acupuncture treatment. A patient does not have a histological problem, but a problem in an imbalance meridien.

Acupuncturists regulate the meridiens and thus the qi in two broad ways. Both too little or too much qi can cause problems. If the patient has too much qi in one meridien, the acupuncturist disperses it by pricking quickly and then putting pressure on the aperture. Too little qi is "tonified" by allowing a needle to sit longer.

Is there a relationship between the Chinese meridiens and Western anatomical features that might explain the effectiveness of acupuncture? Well, yes and no. Although he has not made a careful study, Farish A. Jenkins, professor of Biology and lecturer in Anatomy, says, "Some points are obvious because they block nerves but other sites don't make immediate sense."

Yet in some acupuncture styles such as contact point, the needles never penetrate deeply enough to reach a nerve, leaving Western scientists bewildered. As Dr. Brian Doyle of the Acupuncture Center of Massachusetts says, there are two explanations: "Either the nerve pathways are not defined or the acupuncture meridiens are not related to nerves at all."

Some Harvard Medical School researchers take the latter view, arguing that acupuncture might work by stimulating endorphins, the body's natural painkillers.

Even without explanations, acupuncture is being used to relieve muscle stiffness and bursitis and even to perform facelifts.

But acupuncture is most widely known in the United States for its anaesthetic capabilities. In Japan, most dentists use acupuncture and surgeons prefer it to putting their patients into a deep sleep. But this side of acupuncture is new. Although the techniques and insertion points were complied more than 2000 years ago, acupuncture anaesthesia is only 30 years old and derives from Western influence on Oriental medicine.

Acupuncture is spreading. Many hospitals in Europe use it regularly and UCLA has recently adopted it for many cases.

There are as many schools of acupuncture as psychology, and each has its own history, traditions and even needles. Some use contact points while others insert heavier needles two to three millimeters into the skin. It is an anaesthetic and a therapy for thousands, yet it remains more of an art than a science