I FEEL LIKE my whole life has been renewed," said Otis X. Brown. "I like myself more."

"The doctor asked me how my wife liked it," said Harold Q. Chisholm. "I told him she was going to send him a Christmas present!"

"It" is the inflatible penile prosthesis, the surgically implanted, hydraulically operated device that corrects impotence and ensures erection at any time.

It's one of the latest medical technological marvels, which, along with organ transplants and limb reconstruction, is paving the road to the future and the $6 million man.

Dr. Paul Weisberg, associate clinical professor of psychiatry at the George Washington University, says, "It's one of the great pieces of Yankee ingenuity in this century."

About 3,500 men, most of them Americans, have had the implant operation since the device came on the market in 1973. And they represent only a fraction of those who need the operation.

Estimates of American men who are organically impotent, range from three to ten million. (The latter figure represents 10 percent of the U.S. male population. Some medical authorities say another 10 million are psychogenically impotent.

The operation affects the most intimate aspects of a man's life. Men whose depression-filled lives have ground to a halt because of impotence are suddenly transformed into "new" personalities following the implant. Their self-esteem rises dramatically and they're easier to get along with.

"There are patients of mine who have a whole new burgeoning of life," says Weisberg. "They feel more youthful. They become more creative. A man who had been a novelist, who had stopped writing and was in a depressive hole, had the surgery. He wrote another novel and made a lot of money and became quite well known."

Every man, urologists point out, probably experiences impotence at one time or another from a variety of causes -- fatigue, worry, antibiotics. But the major causes of organic impotence are diabetes, vascular disease, trauma that results in paraplegia, quadraplegia or pelvic damage and cancer of the prostate, rectum and colon.

It's a problem that cuts across lines of color, class and age. Blacks and whites suffer from impotency. So do dishwashers and executives, teenagers and octogenarians.

After airing the subject last summer, the Phil Donahue Show was flooded with hundreds of letters from men and women asking for more information about the operation. Weisberg, who appeared on the program, said most of his mail came from women inquiring for their husbands.

The operation is so new that many physicians aren't aware of it. The first implant patient at Walter Reed Army Medical Center read about the procedure in a newspaper. He told an army urologist who promptly took the three-day seminar required for performing the operation.

Before the implant operation, Clarence Z. Nelson, 45, had been impotent for almost three years. A rare nerve disease had changed him from a happy, healthy person to a depressed and irritable physical cripple.

Nelson rarely left home. He wondered if he was truly a man and feared his wife was losing interest in him.

Ellen Y. Nelson, a 44-year-old government worker, recalls the trauma her husband experienced before his operation:

"I think he had the notion that sooner or later I was going to get tired of it [his impotency] and that was going to be it. He kept trying to impress how important this was and he wanted to keep our marriage going. And I didn't disagree with that.

"I told him it was mind over matter. You have to live with what you can't change. I didn't realize he could change it at that time. I was determined that if that was the way we were going to have to live, then we'd just live that way."

He remained depressed most of the time and stayed inside. "He used to have his little pity parties all by himself," she says. "At first I tried to join him in them, but they never helped. They just made the poor fellow feel worse."

But he's become a new person since the operation.

"From my standpoint," she explains, "his total outlook on life has changed. He never was a person who was hard to get along with. But he became grouchy and short. He couldn't even manage a smile.

"Now he's more open and more ready to participate in other things. He probably hasn't even thought about it, but his other illness doesn't even bother him anymore. He hasn't been in the hospital once [since the implant]."

Already, this technological marvel has changed lives. Husbands, widowers, young and old singles have recaptured their virility. And most women also appreciate it.

"For the man," says Dr. Weisberg, "it's a coming to a new adolescence, where there are new things to master and new combinations to get. The sense of excitement that one sees in these men over the first six months is just wonderful."

The job of treating impotence is as old as the Bible. When the aging King David's virility was not restored by the favors of a young virgin, he renounced his throne.

Impotence is also a theme in 20th century literature. In Faulkner's "Sanctuary," Popeye's impotence is equated with the mechanical civilization that had invaded the South.

For centuries the treatment was usually by way of alleged aphrodisiacs and witchcraft. Not until the late 16th century did surgeons begin theorizing about it. In 1889, a French physician injected an extract from the testicles of dogs into himself and reported that he was rejuvenated.

By the early 20th century, vascular surgery, assuring a greater flow of blood, became a new concept. It wasn't until 1967, however, that it became a surgical procedure, mostly used by European physicians.

The current method of treating organic impotence dates back to the 1930s, when a urologist reconstructed a penis using a section of rib cartilage. The first synthetic material was implanted in the 1950s. These semi-rigid devices are still used widely, but are becoming less popular because of their discomfort and the availability of the new device.

The latter is the brainchild of Dr. F. Brantley Scott, a Houston urologist, Dr. William Bradley, a neurologist, and Dr. Gerald Timm, a biomedical engineer with American Medical Systems, the Minneapolis-based firm that manufactures the device.

Although they all worked on it, Scott originated the idea. Described by Weisberg as "the most ingenious, most inventive, craftiest urologist in the country," Scott said the idea hit him while he was working on an artificial sphincter, a surgically implanted device that would correct urinary incontinence.

"When I first saw the artificial sphincter, the thought occured to me that it could be inflated," he recalls, "and it occured to me that if we could put two cylinders in the penis, we could do the same thing."

Scott works out of St. Luke's Hospital in Houston, where about 430 implants have been installed.

Dr. William L. Furlow, a urologist at the Mayo Clinic in Rochester, Minn., has performed about the same number of operations.

The operation is simple, taking from 40 minutes to 2 hours to perform, depending on the expertise of the urologist and operating room team.

An incision is made just above the penis. Two inflatible cylinders are inserted. They are attached to a fluid-containing reservoir in the lower abdomen. That is connected to a pump in the scrotum near the testes. The pump pushes the fluid through silicone elastomer tubing from the reservoir to the cylinders, making the penis erect. To become flaccid, a man only need press a release valve on the pump, sending the fluid back to the reservoir.

But approval for the operation is granted, patients must undergo the nocturnal penile tumesence (NPT) test to determine if they're capable of erection. Organically capable men will become erect several times a night during sleep, regardless of any emotional problems.

If the monitor measures any erection activity, the patient is rejected for the operation and told to seek psychotherapy (usually, the only exceptions are made for elderly man).

Once a patient has been selected for the operation, he and his wife, or regular sexual partner, are required to undergo one psychiatric counseling session. If that goes well, the operation ensues.

Most urologists report a 95 percent success rate. Infection requiring removal of the device is a complication is less than 5 percent of the cases.

The operation costs between $5,000 and $6,000. Patients are advised to have a good health insurance or lots of cash.

Placing the cylinders in the penis is a delicate and painful procedure that leaves the organ sore for several months afterward.

"It was the most painful operation I've ever had," says Chisholm. "The first couple of months it hurt to walk; sit down or even stand up. But I had looked forward to this. I thought it would be better than nothing -- better than taking a cold shower! You know, if you're sexually aroused and you can't get an erection, that can be pretty disheartening."

Because the device is relatively new, psychiatrists are just beginning follow-up evaluations on patients and partners.

"My impression is that the wives are usually delighted," says Weisberg. "One reason is that women's sex drive tends to stay up longer than men's. So that by the time a couple is 55 or 60, there is usually an equal sex drive or a slight disparity on the side of the wife. So when a husband regains his potency, the wife is going to be very pleased.

"But I have seen wives who have responded with hostility, thinking it was a competition. The husband is repowered in terms of his ability in the marital competition and it puts the wife down."

"Of course," he said, "impotence is used in marriage as any other debility. But any debility will lead to a shift in balance in the marriage. Sometimes that shift is a power shift, sometimes it is a responsibility shift or maybe a satisfaction shift.

Dr. Harvey L. Resnik, a psychiatrist, and his wife, Audrey, a psychiatric nurse, who have treated about 45 implant patients, say they caution couples that intercourse may be different afterward.

"The normal human sex organ has a certain amount of give to it," they say. "But the implant has a certain rigidity and has the potential for hurting the partner."

"We're short-circuiting the process nature has given us," they say. "We now have an instant penis, and men might get the desire for instant entry. Some women feel left out."

The Resniks, who trained under sex therapists Masters and Johnson in St. Louis, provide therapy for wives, or partners, as well as husbands.

"People should follow guidelines. Please don't hit the button the moment you hit the bed. Allow your partner to hit the button once in a while."

So eager are they for the device that patients rarely raise ethical questions about the operation. "There's not much of an ethical or moral element attached to it," says Weisberg, "because you're restoring the capacity for fathering. A person is acting in his own behalf to increase his own levels of capacity to procreate. As such, that's not sinful.

"It's less of an ethical question than a shame question for men. Men feel very shameful about their ego. They don't want to advertise their position."

Unlike most couples, Peter J. Q. and Jean X. Knight have no trouble talking about the device. They've even told their teen-aged sons.

But the Nelsons have been close-mouthed. Says Ellen Nelson: "I don't want people to look at us walking down the street and say, 'Look at the couple that has that thing.' I don't want people to think we're freaks. It's a very personal, private thing."

As the 95 percent success rate suggests, the overwhelming number of men are satisfied with the operation -- and they encourage others to undergo it.

Dr. Myron I. Murdock of Bowie and Dr. David G. McLeod of Walter Reed Army Medical Center, the urologists in the area who probably have performed the most implants, say their operating schedules for the device are getting crowded.

Murdock has implanted 55 devices since 1973 and McLeod has installed 16 in almost two years.

The implications of the operation are far-reaching. While enhancing the sexual activity of many couples, it may, some fear, further the depersonalization of sex. One urologist says he has already been approached by homosexuals and men involved in male call services and pornographic movies to perform the operation.

Others wonder whether the restrictions on psychogenically impotent men may soon be relaxed, possibly paving the way for a psychopath to obtain the device and perhaps use it for rape.

Nevertheless, the implant is in its infancy now and most people think primarily of its good effects.

"Men don't have to accept impotence any longer," says Weisberg. "It's no longer a matter of accepting that it's just old age or that 'Uncle George lost it when he was 65, so why shouldn't I even though I'm only 32.' I think it's a major advance."

Names of the patients in this article have been changed to protect their privacy .