" ''I believe the day will come when most of us will have something similar to the VeriChip under our skin,'' said Scott Silverman, president of Florida-based Applied Digital Solutions. "

The painless procedure barely lasted 15 minutes. In his South Florida office, Dr. Harvey Kleiner applied a local anesthetic above the tricep of my right arm, then he inserted a thick needle deep under the skin.

''First we locate a prime spot,'' he said. ''The next thing is to release the button that triggers the injection mechanism, and that's it, the cargo's been delivered.''

The ''cargo'' was a half-inch-long microchip inside a glass and silicone cylinder that carries my permanent identification number. For an instant, I remembered the famous scene in the movie ''Fantastic Voyage'' in which a miniaturized Raquel Welch and her companions are inserted, submarine and all, into the vein of a patient. In my case, the tiny chip inside me can transmit personal information to anyone with a special handheld scanner.

Theoretically, this VeriChip will allow doctors to call up my medical records even if I'm too badly hurt to answer questions. It is also supposed to allow me to get money from an automatic teller machine by flashing my arm instead of punching in my PIN number. Or reassure airport security that I am a journalist, not a terrorist.

And, though the VeriChip strikes critics as Orwellian, its makers think the surgically implanted IDs could be the Social Security numbers of the future in a nervous world.

''I believe the day will come when most of us will have something similar to the VeriChip under our skin,'' said Scott Silverman, president of Florida-based Applied Digital Solutions. ''People will regard that its benefits -- in terms of financial, security, and health care -- far outweigh the possibility of loss of privacy.''

Right now, I am part of a very small club, the 18th person in the world -- and the first journalist -- to get ''chipped.'' Most of the others are ADS employees along with one Florida family who have been jokingly dubbed ''the Chipsons'' in a play on the old Jetsons cartoon.

The idea of a system that gives emergency workers and others immediate access to potentially lifesaving information is exactly what drew the Jacobs family of Boca Raton to the VeriChip. At the request of their 14-year-old son, Derek, the Jacobses got chipped last year.

''My husband has cancer and we've experienced the frustrating delays of trying to provide urgent medical history information every time he is rushed into the emergency room,'' says Leslie Jacobs.

Since the attack on the World Trade Center on Sept. 11, 2001, she continues, ''we know that our lives are increasingly vulnerable. If we want increased safety, security, and peace of mind, we need to take positive steps. We've decided that having a VeriChip is one way to do just that.''

But critics see surveillance technology like the VeriChip as a growing threat, giving potentially dangerous new power to businesses and government alike. In a report issued in January by the American Civil Liberties Union, Jay Stanley and Barry Steinhardt warned that an explosion of technology has already created a ''surveillance monster.''

''Scarcely a month goes by in which we don't read about some new high-tech way to invade people's privacy, from face recognition to implantable microchips, data mining, DNA chips, and even `brain wave fingerprinting,' '' they wrote. ''The fact is there are no longer any technical barriers to the Big Brother regime portrayed by George Orwell [in his novel `1984'].''

The VeriChip is similar to the more than 25 million chips already embedded in animals all over the world acting as ''pet passports,'' allowing customs officials to monitor those animals that do not need to go into quarantine, or to identify your stray dog.

But, at least for now, the VeriChip does much less: it's mainly for demonstration purposes, carrying only an identification number and the capacity for about three paragraphs of information. Only 10 hospitals and doctors in Florida have the scanner to read the chips. And the Food and Drug Administration has not yet approved the chips for use in health care, so they cannot be used to access medical records.

However, ADS officials say this is just the beginning. They want to build a chip that can store loads of information, or act as the key to a central database that stores information about the user. Ultimately, the company hopes to be able to track the movement of people with chips worldwide using global positioning satellites.

The company is field testing its Personal Locator Device, or PLD, which ADS says could help track lost children, sick elderly family members, mountain climbers who get lost, or kidnap victims. Company officials say they have been inundated with requests from private companies in Latin America, especially Mexico and Colombia.

The PLD is still years away from wide use, according to Keith Bolton, ADS's chief of technologies. The working prototype is rather large -- 2 1/2 inches in diameter -- and would require major surgery for implantation (though it appears some Israeli secret service agents already carry something similar). It is powered by a pacemaker battery, and, just like in a Tom Clancy book, it would let anyone with access to the PLD system follow the wearer anytime, anywhere in the world, at the click of a mouse.

''The PLD would also monitor the vital signs of the wearer, and the environmental conditions around that person, and it could be a great way to protect a family member with a disease such as Alzheimer's,'' says Bolton.

Businesses already use technology to track their products around the world, but we should stop and think about the implications before starting a human tracking system, cautions Mohan Tanniru, professor of information systems at the University of Arizona.

''I am not going to put a chip on my kid thinking that she could be kidnapped,'' he says, ''unless I know the chip will be activated only if I report that my kid is lost. But how do I know that the police are only going to activate it when I say so, and not when they feel like it? You can't just say that technology is bad just because it is there. So it is a matter of deciding what trusting agency should be given that responsibility.''

Tanniru actually thinks that human tracking might be welcome in certain cases, such as following criminals on probation or making sure foreign nationals don't overstay their visas. In fact, Pro Tech Monitoring of Tampa already makes an externally worn tracking device for parolees that alerts authorities if the wearer enters a forbidden area, such as a school zone.

For ADS's Silverman, both the VeriChip and its future GPS-based version are a matter of individual choice.

''No one is forcing you to have a VeriChip. If you want a chip in your right arm you are going to know it is there because you will see it injected. When you look at the events of 9/11 and the way people measure their own personal security today versus the way they did a few years ago, there is a much higher concern to make sure that family members are safe and sound, and some people now put that above privacy rights.''

So far, ADS's technology gamble has not translated into profits. In 2002, ADS lost $112 million on revenues of $96 million, though this loss is significantly lower that that of the previous year.

As far as I am concerned, having a chip with a code in it is not giving me the chills. I think it would be nice to use it to get cash or pay for gas, and I wouldn't mind paramedics having access to my health records in the blink of an eye. Besides, I know it would never get lost. I did, however, have a few questions about its health hazards. So I asked Dr. Kleiner.

''The VeriChip is extremely safe,'' he says. ''Pacemakers are hundreds of times larger and more complicated and nobody has problems with them. To prevent the chip from migrating to another part of the body there is a little polymer at one end of the capsule that will adhere to the skin and hold it in place.

At his office, my arm was like a barcoded product at a supermarket cash register: It beeped every time the scanner prodded the chip. It worked even through my clothes. Displayed on the screen was a long number with many zeroes. For good or bad, I thought, this chip may be quietly heralding a time when people will literally have technology under the skin.

http://www.boston.com/dailyglobe2/140/science/Barcoding_humans+.shtml