The blood-pressure reading was fine, and now the veterinary anesthesiologist picked up a small, electric hair clipper to clear a patch of fur from my dog's foreleg, just above the paw. This was too much. Stoic through patient intake and the tightening of the blood-pressure cuff, he now turned his head toward the whirr and chick of the blades and began to quaver in a way I'd never seen.

"He's probably just picking up on your anxiety," the vet tech said. There was reproach in her tone, but I wasn't in a position to argue. So I nodded and tried harder to act like a $1,400 veterinary brain scan under general anesthesia was no big deal.

But the dog knew better, and so did I. Looking down at my boon companion for more than half of my adult life, I thought, "I hope this is the right thing to be doing."

Bear was a mutt who looked a lot like a black Labrador, until you stood him next to one. He was 14, and he'd always been hale. He'd survived falls through pond ice, fracases with raccoons, tangles with rusted barbed wire, a tumble from a mountain catwalk, periodic midnight rambles (mostly solo and unscripted), transatlantic air travel and even a bounce off the bumper of a moving car. He could wriggle through spaces where only a pancake could fit, and he was always just as enthusiastic to be home from his travels. Nothing fazed him, except thunder and, oddly, brooms. It was part of his charm.

My most recent experience with major veterinary care had been way back in the '70s, when visits to the vet with the family dog never involved anything more complicated than a rabies shot or a worming pill. Back then, 10 years was old age for many dog breeds. Dog food came in huge bags at the grocery store and poured in mysterious shades of chemical orange and bright brown.

But now, we were uneasy pilgrims in a strange new world, where we never seemed to get out of the clinic for less than $250 and our first real sick visit cost $900, more than I'd ever spent on one doctor visit for myself.

Bear's symptoms were mysterious; the diagnosis was elusive. He was sluggish, he had loss of sensation in his paws and mysterious fevers -- and he wasn't getting better. The regular vet diagnosed a thyroid condition, but beyond that, he was stumped. He sent us on to a veterinary neurologist, who, suspecting a brain tumor, had sent us here to Vienna, to the Washington area's only commercial veterinary MRI facility -- the Iams Pet Imaging Center.

"Believe me," the center's senior veterinarian, Pat Gavin, a professor of veterinary radiology at Washington State University, had told me, "if George W. Bush were getting an MRI, he wouldn't be any better monitored than the animals at this facility."

In the scan room, white-coated technicians with clipboards squeaked back and forth across the gleaming white floor, noting patients' vital signs every five minutes. The center's chief, Julie Smith, one of a handful of board-certified veterinary anesthesiologists in the country, presided over this reassuring tableau with a kindly competence that generated immediate trust. Smith had spent four years in postgraduate veterinary study learning how to safely anesthetize dogs, cats, lizards, hawks. MRIs were all they did here, and they seemed to do them very well.

Still, I was having trouble wrapping my brain around the idea. The civilians I talked to weren't much help.

"An MRI for a dog?" said an acquaintance. "You're kidding, right?"

She shook her head. "What you need is an old-fashioned country vet," she said. She had a friend who'd had three ancient dogs, and when their time came they were "put down," and that was that.

"The old-fashioned kind of vet," she said firmly. "That's what you want."

But did I? And what did that mean, anyway? True, I'd always been a fan of the old-fashioned approach, the approach enshrined in books like James Herriot's All Creatures Great and Small, where the vet is kindly and competent and does things the old-fashioned way. In principle, at least, I was as irritated as anyone by the unceasing, often pointless-seeming innovation of modern American consumer life, the incessant alarms about the dangers of this toxin or that. In fact, part of the appeal of having a dog had always been the connection it seemed to offer to a simpler way of life.

And now we were in the middle of a $1,400 brain scan. And if there was a brain tumor? How I would know how much medical treatment was right and how much was too much? And how much could I afford? Already we were flying on credit cards; I'd just refinanced my house to pay off debt, and now the numbers were rising again.

At the veterinary specialty clinic, the waiting room was full of other people seeking similarly sophisticated treatments. We might have discussed this, but we were all locked inside our own compartments of worry. And there was something else. I recognized the look immediately: It was the determinedly upbeat expression I'd been wearing for months, a mixture of anxiety and the desire not to offend the veterinary pros upon whom we were now very dependent. It was hard to get these appointments -- specialists like veterinary neurologists were in such demand that veterinary schools were having trouble keeping enough on hand to teach. So, far be it from me to make waves by asking whether anyone else was as surprised by these prices as I was.

As Bear slipped off into the ether for his MRI, I was sent back to the waiting room. I was flipping through the dog magazines when a man carrying a small black-and-white Boston terrier came in the front door. They'd just driven up from North Carolina, the man said. This was the only veterinary MRI facility between home and Philadelphia, he said, and he felt very lucky to be here.

Me, too, I replied. We talked a little more and then fell silent.

IN A CAVERNOUS, CONCRETE-FLOORED EXAMINING HALL at the Leesburg campus of the Virginia-Maryland Regional College of Veterinary Medicine, a fourth-year student stood in the shadow of an enormous caramel-colored draft horse. Heather Craven, 32, was using a white plastic disposable razor to shave a small patch on the horse's neck, preparation for a catheter through which a large sack of blood would be drawn.

"There we go," Craven said as she worked. A stethoscope peeked out from the back pocket of her baggy, blue jumpsuit. A pile of bloody plastic tubing and gauze bandages awaited cleanup at her feet. In the background, a walkie-talkie announced the imminent arrival of two emergency cases, a horse with severe colic and a broodmare in the last stage of a difficult pregnancy.

Fellow student Kelly Malec-McConnell stood nearby with a clipboard. A large, O-shaped bruise was fading from purple to dark red around her right eye. A horse she'd been treating had kicked as she'd injected an anesthetic into its leg, as part of a diagnostic test for lameness called a nerve block.

The emergency cases meant that a scheduled gastroscopy -- in which a tiny camera on a tube is threaded through the horse's nose and into its gut -- would have to be postponed. In a room across the hallway, meanwhile, a small brown horse stood passively as an X-ray machine mounted on a crane and dolly rotated around its middle. The digital images were relayed to a computer screen in the next room, where a veterinary resident inspected them for clarity. In still another room, a horse stood chewing hay and drinking water, quarantined until it excreted radioactive isotopes injected during nuclear scintigraphy, a test used to pinpoint the source of lameness.

Welcome to a routine (and therefore anything but routine) veterinary school clinical rotation, circa 2004 -- a mixture of old-fashioned bloodletting and nuclear medicine and everything in between. Craven and Malec-McConnell, rising seniors at the main veterinary campus in Blacksburg, Va., were in the final months of preparing for a career that will be expected to embody both the veterinary profession's simpler past and its demanding, high-tech future.

In addition to the traditional course work -- about 60 percent of it in small-animal medicine (i.e., dogs and cats) -- their $200,000, four-year veterinary educations include instruction on the human-animal bond and the importance of good vet-client communication: personal touches such as sending a note when an animal in their care has died. "Even horses have gone from being farm workers to people's companions," Craven said. "That course did a good job of making it clear that the relationship has changed -- that people are willing to spend the money on their animals. And they want to spend the money."

That recognition is one small part of a sea change that began in the late 1980s, driven by technological innovation and the rising social status of the American house pet. At the country's leading veterinary teaching hospitals, surgeons now routinely perform procedures that were unavailable to the average house pet 10 years ago: kidney transplants, cancer chemotherapy, back surgery for herniated disks, titanium hip-joint replacements, radiation treatments for goldfish, MRIs for hawks. Even treatments once reserved for very expensive animals -- racehorses and champion purebred dogs -- are available at the sophisticated specialty hospitals that have proliferated in the past decade and that provide a range of care previously available only at the nation's 28 veterinary school teaching hospitals.

"In the 1980s, pet owners began to say, 'If medical science can remove my cataracts, why can't it take out my dog's?' " says Jack Walther, head of the American Veterinary Medical Association, the profession's primary membership organization. "And the answer was, we could. We'd just never been asked."

Until the 1940s, and through most of its history, veterinary medicine was devoted to helping agriculture manage its food animals. The creed of veterinary medicine -- to help society by helping animals (as opposed to helping animals themselves) -- reflects this. Until the 1960s, most vet students were men with a background in farming or animal science. As the United States suburbanized in the 1950s, small-animal veterinary practices began to proliferate, but pet cats and dogs still spent much of their time outside. (Try to picture Lassie sprawled lengthwise on the living room couch at Timmy's house. It can't be done.) As recently as the late 1980s, most pets were treated as second-class citizens by their owners.

The practice of veterinary medicine reflected this lowly status. Even now, most veterinarians carry little or no malpractice insurance, because until very recently, it was impossible for a pet owner suing a vet over loss of a pet to recover anything more than the animal's replacement value. The bigger part of the vet's week was spent administering vaccines and fixing the broken bones that were a common and unremarkable fact of life in the decades before leash laws. When a pet's medical problems became difficult or expensive to fix, the animal was "put to sleep," or euthanized.

"One of the most discouraging parts of my practice in the early days was having a dog come in with a simple broken leg and having the owner say, 'Well, it costs money and it's just a dog, so put him to sleep,' " says Walther, who began his practice in Nevada almost 40 years ago.

In the late '80s, however, pets began to fill the emotional and physical void created by rising divorce rates and growing numbers of single-person and childless households. "A pet may be the most stabilizing, permanent presence a child from a divorced home will ever experience," says Arlington vet Robert Brown.

Dogs and cats began to live longer, too. From 1987 to 2000, the life spans of the average dog and cat increased by more than one-third, thanks to better commercial pet foods and widespread vaccination, according to the AVMA. But longer life spans meant a jump in the incidence of the diseases of old age -- cancers, organ failure, crippling arthritis and other problems. With the family pet now ensconced on the bed instead of at the far end of the yard, the medical problems were easier to spot and harder to ignore.

Today, many people think of their pets as members of the family, and they want them to have access to the same medical technology they do, vets say. And this is possible, thanks to the same biomedical revolution that transformed human medicine in the 1950s and '60s. According to the Food and Drug Administration, which regulates drugs for the veterinary market, the pharmaceutical industry in recent years has begun shifting its energies away from the agricultural market and toward companion animals. The number of new drugs approved for veterinary use has increased dramatically in the past decade, with special interest in drugs for behavior modification and pain relief.

The focus on pain medication is a particularly significant bellwether. Until very recently, desensitizing veterinary students to animal pain was an important part of their education. "When I went to vet school back in the Stone Age, we didn't really talk about pain," says Stephen F. Sundlof, director of the FDA's Center for Veterinary Medicine. "It was, 'Do the surgery, and the animals will get along fine.' " Today, Sundlof says, there is a growing understanding of pain as a complication that impedes recovery and healing.

This gradual and ongoing "evolution in consciousness," says Elliott Katz, a veterinarian and founder of the advocacy group In Defense of Animals, has been spurred by the entrance of large numbers of women to the profession in the past 15 years, and by the demands of pet owners, whose economic clout is becoming a counterweight to the agribusiness interests that have traditionally underwritten much veterinary research at universities.

All of this has put new pressure on the ordinary neighborhood veterinary clinic. Vets, who 30 years ago needed little more than a stethoscope and an Army surplus field X-ray machine to set up a practice, now equip their clinics with an array of expensive diagnostic equipment, from blood-analysis machines to ultrasound scanners. Even setting up a small practice costs upwards of $500,000.

The average veterinary bill -- which has tripled in the past 10 years -- reflects this. The price surge was not an accident. It is the direct result of a half-a-million-dollar study commissioned by the leading veterinary professional organizations in 1998 to figure out why veterinarians' salaries lagged far behind those in human medicine and in such professions as law and engineering. The study, by the business consulting firm KPMG, cited federal statistics showing that veterinary practice incomes had declined during the 1990s, a decade when many other professional incomes rose.

The study concluded that veterinarians were failing to run their practices as the demanding businesses they had become. Pressed by competition, vets were mortgaging their practices to buy expensive equipment but charging clients prices that hadn't increased much since the 1970s. The veterinary profession called the study's findings a "wake-up call" and set up a national commission dedicated to encouraging vets to concentrate harder on the bottom line.

These days, veterinary school graduates enter a profession more focused on management economics than ever before, and one in which ethical questions long familiar to human medicine are only now beginning to surface. Veterinary malpractice cases, once rare, are on the rise. State courts have begun awarding aggrieved pet owners sums as high as $30,000 for pain and emotional suffering, instead of limiting damages to simple replacement value of the animal, as in the past. Veterinary insurers say this change will drive up costs, but others, including some vets, say the change is inevitable and overdue. "Vets can't come into the examining room saying, 'What's wrong with your baby? What's wrong with the little boy?' and then, if they make a mistake that kills the baby, act like they broke your . . . ashtray," says Robert Newman, a California veterinary malpractice lawyer.

Even the nature of pet ownership itself is under review. In the past five years, more than 40 jurisdictions across North America, including the state of Rhode Island and the city of Windsor, Ontario, have approved ordinances that transform pet "owners" to "guardians," a change that proponents hope will lead to better treatment for companion animals. (Critics fear that giving vets the authority, and even the responsibility, to report animal neglect or abuse will discourage pet owners from going to the vet at all. So far, however, the debate is academic. No charges have been brought against pet owners as a result of the new wording, and Newman and other legal experts say the new language is largely toothless.)

The human-animal bond had been rewritten in my household the day Bear joined it. As an enthusiastic member of the roll-in-the-dead-squirrel society, he wasn't allowed on the bed or the couch, but in all other ways he was a member of the family. The sicker he got, the more all of these philosophical questions were thrown into sharp relief. And I wasn't the only one grappling with them.

"Twenty years ago, if your dog had congenital heart failure or an arrhythmia, you might just be told, 'There's not much we can do,' and that was upsetting, no doubt," says Nancy Kerns, editor of the influential Whole Dog Journal, a national magazine. "But it's also quite upsetting to learn there are things that can be done and it's going to cost you $10,000 or $15,000 to do them. At that point, you're making serious financial decisions, and that's a lot of pressure for some people. There's so much available that it can really cause a hardship . . .

"You're usually in shock when the crisis has struck, and you're in crisis-management mode, and you try to do whatever you can, which you suddenly learn is a great deal."

I HEARD HIM BEFORE I SAW HIM. He was barking continuously, deep bass yelps with a clear undertone of panic. An investigation behind the abandoned chicken coop of a mountain farm north of Frederick revealed a small black dog, emaciated, and tethered to the ground with a length of rusted chain thicker than his foreleg. He appeared to be about a year old. He had a short black coat, a head sleek as a seal's, lively brown eyes and floppy ears.

He was being detained for the crime of chasing sheep, a serious offense in farm country, and was on his way to the pound. He was in trouble, and he seemed to know it. In between barks, he leapt two feet straight up, like a piston, until his tether yanked him back again. He had a nub where his tail should have been, a stub that whirled with excitement, clockwise, then counterclockwise, like a helicopter rotor shorn of its blades. There were scaly spots on his lower legs that would turn out to be a fungal infection.

The man who'd chained him up was a fitfully employed Vietnam veteran with two young kids and a dog of his own to look after. He was leasing the farmhouse but was months behind on rent and was leaving for Florida soon. The dog had been left behind by a weekend deer hunter from Gaithersburg, he said.

"He won't eat," the man said.

The no-appetite defense fell apart momentarily, when Bear wolfed down two bologna sandwiches, then sat politely, cocked his head and waited for more.

"Believe me, you don't want that dog," the man said.

But I did, and two days later, I had him.

"Good luck," the man said. "You're gonna need it."

As it turned out, he was my luck, instead. Over the next 13 years, he was a guide and companion into worlds I never would have discovered on my own. We walked in the mornings, in the evenings and late at night. He forced me out into the living world that so much of modern life conspires to obscure. We saw rabbit holes, deer tracks, raccoons and foxes, and heard the unsettling scream of owls long after dark.

He was everything to me, but he couldn't be everything. A dog, any reasonably sane dog lover knows, is not a child, a substitute spouse, a burglar alarm, status symbol, psychotherapist or even a friend, not in the human sense anyway. A dog is a dog, which turns out to be more than enough.

It's true that, once, a sister-in-law of mine, trying to explain my dog and me to her 4-year-old daughter, had said: "That's Bear -- that's Aunt Mary's baby." I winced, but only a little. As shorthand for a 4-year-old, that wasn't bad.

By age 10, what a friend described as Bear's "rambunctious good cheer" had mellowed. He feinted lunges at neighborhood squirrels instead of giving actual chase. By 12, he was having serious trouble on stairs, and his face was white around the eyes and muzzle, giving him the look of a wise raccoon.

I met each small loss with fierce resistance. Trouble on the porch steps? My boyfriend built us a ramp. Paws slipping on the bare floor? Rugs were laid. Need a boost up the attic staircase each night? I boosted away, and lay awake afterward designing hoists made of climbing rope and carabiners.

He was old, yes, but what was old? In the veterinarian's office a brochure announced that the traditional formula for gauging a dog's age in human terms -- one dog year equals seven human years -- had been replaced by a new formula that multiplied the dog years by four or seven, depending on the year. A canine Dorian Gray, Bear went in one afternoon from 91 to a relatively sprightly 76.

But the day came when what had seemed mere old age began to look more like disease. Bear was stumbling regularly now, held his head to one side at times. His reflexes were ever slower, and some days he hopped across the yard as if it were covered in hot coals. The regular vet, stumped, sent us to a specialist.

The veterinary neurologist worked out of one of this area's handful of sophisticated specialty practices, where you needed your own vet's referral to get in the door and the vets on hand had done postgraduate study in everything from cardiology to ophthalmology. This practice was in a nondescript shopping center in Springfield, but inside, the bright, airy waiting room was as upscale as a Chevy Chase living room. I could tell we'd entered serious wallet-surgeon territory, but that seemed reassuring, somehow. I had been chasing a diagnosis for months and come up empty. It was time to call in the big guns.

The neurologist watched Bear walk up and down the hallway and then outlined a diagnosis. He suspected a brain tumor, he said. An MRI would be the only way to know for sure. It would cost about $1,400. If it was cancer, radiation therapy (with a price tag of $1,500 to $4,000, depending on how many years of remission I was hoping to buy) was one treatment option. Or we could just treat the symptoms with steroids, in which case the cancer would advance.

Radiation treatment was frequently successful, he said. In fact, dogs seemed to tolerate it better than humans. If there was no brain tumor, a spinal tap would be the next diagnostic step. I okayed the scan. Anything that I could afford, or charge, so long as the dog wasn't suffering, was my credo. I'd already spent about $2,200, but I'd heard of people who'd spent more. There was the couple I knew who'd paid out $14,000 treating their dog's stomach cancer. The regular vet had told me about clients who'd stopped buying their own medicines or pawned valuables to raise money for a pet's treatment.

IT WAS COCKTAIL TIME in Maura Hall's kitchen in Laurel. Outside, four cats lolled on flagstone warmed by the late afternoon sun. Inside, a fifth cat, a former stray turned queen of the household, was perched on the kitchen table, preparing to down her customary pre-dinner pharmaceutical. Hall stood at the counter, drawing a few drops of the immunosuppressant drug cyclosporine out of a tiny bottle with a small hypodermic needle and injecting it into a capsule. To this she added an antibiotic to fight a fungal infection, a steroid called prednisolone and insulin for the cat's diabetes.

Lily, a longhaired, gray Maine coon-type with a pushed-in nose and enormous, feathery tail, received her new kidney last year. The medicine is part of her post-transplant regimen. She takes it every 12 hours and will need it on that precise schedule for the rest of her life. She is a good patient. This afternoon, as usual, she swallowed her medicines without complaint, gave her paw a lick and, with a look of fastidious forbearance, jumped off the table and sauntered to the food dish where dinner awaited. Monkey, the donor cat, a lab animal adopted by Hall as part of the transplant program, waited outside with the other cats until Lily was through.

"I'll be doing this for the rest of my life, or hers," Hall said cheerfully, closing medicine bottles with the efficiency of a pharmacist. The divorced mother of a teenage daughter, Hall has spent more than $25,000 for kidney transplant surgery and follow-up care at the University of Pennsylvania's veterinary hospital. The transplant itself cost about $8,000. Complications (including a second surgery), weekly blood tests at $200 each and medicines have driven the cost up from there.

Although the total was far more than she expected, Hall says she has no regrets. She sees Lily and herself as foot soldiers in science's war against feline kidney disease, which is epidemic in the United States. "It's not for everybody," she says of the transplant surgery. "In the initial phases, our whole life was turned upside down" by frequent trips to Pennsylvania for pre-transplant testing and treatment and then the surgery itself. "But to see this cat now -- she's fat, she's happy, she's jumping on top of the couches. To me, it doesn't matter whether it's a human life or an animal life. Who was I to say, 'You know, I can't do this' or, 'It's too much trouble' or, 'People are going to think I'm nuts.' I just went with it. I went with what I thought was right.

"And I've gotten so much from this. I'm just a better, more optimistic person. I've been able to think, and study and learn new things, participate in life instead of just going along."

Hall, a former professional horse trainer who now sells motorcycle parts, has euthanized dogs and horses over the years. She is not sentimental about animals, she says, but there was something special about Lily, who blew into her father's yard during a hurricane in 2001, a time when Hall had just lost her mother to cancer.

Still, at times, during the lengthy transplant procedure, she wondered.

"It's a huge roller coaster -- ethical and emotional," Hall says. "You ask yourself: Is this the right thing? Am I interfering with the natural progression of things?"

"You hear it all the time: 'Why in the world would you spend all this money on a cat?' " agrees Lily Aronson, a surgeon and faculty member at Penn who has done some 75 transplants since the program was started there in the late '90s. "The answer is: 'I don't drink, I don't smoke, I don't go out and blow thousands of dollars gambling in Atlantic City . . . So, if I decide to spend my hard-earned money on my animal, that's my decision.' "

But it's a decision that can be a lightning rod, nonetheless. Hall received hate mail after news of her cat's kidney transplant appeared in local newspapers, and there is a segment of the American public for whom the idea of spending tens of thousands of dollars on a cat's medical care when so many humans don't get even basic care is, if not incendiary, at least highly objectionable. It's a further sign, this argument goes, of a culture that has lost its moorings.

And in online chat rooms devoted to feline kidney failure, Hall sometimes runs into yet a third perspective: resentment and guilt, from pet owners who've had to forgo transplant treatment for financial reasons. "I can understand it," Hall says. "They're buying time, just trying to make their cats comfortable, and then they hear from someone like me."

The question of access is "the driving ethical question in veterinary medicine today," says Arthur Caplan, chairman of the department of medical ethics at Penn. "I can assure you that if your cat or dog is hit by a car in a poor neighborhood, you're going to have the choice of euthanasia or hoping that the animal will come around. In a rich neighborhood, you're going to get a whole recipe of things you might consider doing: orthopedics, the possibility of dialysis, lots of things that would be similar to what happens with human trauma."

"In general, it's a sort of tough question of, Do you get your money's worth . . .," Caplan says. "I think that sometimes the economic forces, on the part of the vet, and family guilt, line up to promote treatments with only a remote possibility of success."

Katherine Karamolengos agrees. Her cat, Leo, was one of the early patients in Penn's feline kidney transplant program. Leo survived for three years and six months after surgery, but much of that time was spent battling the complications (diabetes, anemia, intestinal ulcers, Cushing's disease, liver cancer) that are routine in human transplant patients taking immunosuppressants, the drugs that keep the body from rejecting a donor organ. The original estimated cost of the transplant, about $4,000, ballooned to seven times that.

"Faced with similar circumstances, I wouldn't do it again -- absolutely not," Karamolengos says. "No one explained to us before the surgery that there could be such terrible complications, that there would be such a terrible burden financially."

Karamolengos's online research had led her to believe the cost of post-transplant medicine would be about 49 cents a day. Instead, cyclosporine cost her $450 for a bottle "the size of a thimble" that lasted two months.

"I think the public should be educated and know what they're getting into when they consider high-tech and experimental procedures," she says. "Because everything is very expensive, and you don't get a break."

Some vets worry that high-tech diagnostics could someday overwhelm the physical exam, the cornerstone of veterinary medicine. "I hope we never get to the point where first all the diagnostic stuff is done and then you look at the animal. It kind of looks like it's going that way," says Arlington vet Robert Brown.

In veterinary medicine, Brown says, "people want answers, and they want them quick. It's just not acceptable to do a lot of sophisticated testing and say, 'We don't know.' There's a lack of understanding that this is the same medicine that is done on people."

It is not exactly the same medicine, however. Many pet owners do not realize that the FDA's approval process for veterinary medicine is far less rigorous than the one for human medicine. Human drugs typically are tested on tens of thousands of people before reaching the market. With veterinary pharmaceuticals, for reasons of cost, that number is much lower, according to the FDA, often in the low hundreds. "In reality, when new drugs are released in the marketplace, the first two years of animals using it are the actual test population," says the Whole Dog Journal's Kerns.

That has been the case with a family of drugs known as non-steroidal anti-inflammatories, which have been widely and successfully marketed in recent years to relieve arthritis pain in older dogs. Ten months after the first of those drugs, Rimadyl, hit the market in 1996, the FDA's Center for Veterinary Medicine had received hundreds of reports of serious, sometimes lethal, side effects in dogs that were taking the drugs. In the wake of those reports, according to the FDA, the drug's manufacturer, Pfizer, met with the FDA, revised and expanded the drug's list of serious side effects and sent out a "Dear Doctor" letter warning vets to use greater caution when prescribing Rimadyl and similar drugs. More recently, the warning has expanded to include an advisory against switching between different brands of the same drug concurrently.

With the variety of veterinary pharmaceuticals increasing all the time, some critics worry that busy vets may rely too heavily on pharmaceutical company salesmen for their information about the efficacy and safety of new drugs. "The vets tend to flip through the pamphlets [from the salesmen] and say, Yeah, that sounds good," Kerns says. Too often, Kerns says, pet owners leave the veterinary clinic with prescription drugs but without the warning circulars that human patients receive as a matter of course.

Nonetheless, the demand for new medicines and better diagnostics is expected to soar in the coming decade.

"There are so many treatments and technologies and things to try," says Penn's Caplan. "In America, we say we have ambivalence about technology, but I don't believe that for a second. . . . In America, by the time we start talking about turning off the machines, either for our relatives or our pets, in most parts of the world they've already been buried."

IF VETERINARY MEDICINE at times seems like a no-win choice between doing too much and doing nothing at all, there are vets who are trying to imagine another way.

In a storefront on the outskirts of Columbus, Ohio, in a clinic tucked away between a Papa John's pizzeria and a KFC outlet, a red-haired visionary named Tami Shearer is doing just that.

Shearer's three books about pet care and her pioneering use of new treatments -- a paw gauge that measures pain by recording changes in the electrical conductivity, low-level laser therapy to treat arthritis and post-operative pain -- helped make her the Hartz Mountain Veterinarian of the Year in 2003. In her veterinary clinic, there are more signs of a creative mind at work. The examining rooms, for example, have glass-paneled doors, which reduce the stress many animals exhibit when enclosed in a small, windowless room.

Perhaps Shearer's most innovative work is in the bright, airy examining area next door, where she is operating one of a handful of pet hospices in the country. The idea is similar to human hospice -- to relieve the suffering of animals with chronic or terminal illness. The care includes the use of narcotics like morphine to manage severe pain and low-tech therapies like massage to improve circulation. There is also psychological counseling, financial assistance, even housekeeping help for pet owners drained by the demands of caring for severely ill animals.

"We used to think, 'Okay there's either death and suffering or there's euthanasia, and there's nothing in between,' and that's not true," Shearer says. "So at the hospice, we talk not about prolonging suffering, but improving the quality of life until it's the right time for euthanasia, or until there's suffering we can't control. It seems to give a lot of people comfort to know there's that gray zone in between."

Unlike human hospice, where patients typically are in residence, pet hospice teaches people to care for their ailing animals at home, offering lessons in practical but not necessarily obvious mercies such as moistening the mouth and eyes of a dying animal with water to keep it comfortable. And there is more technical instruction, too.

On a recent morning, Shearer sat in hospice with Stanford Apseloff, a lawyer and longtime client whose 19-year-old cat, Isabel, is dying of lymphoma. Isabel beat cancer eight years ago but had recently relapsed. Four months ago, convinced that there was no hope of cure, Apseloff, with Shearer's help, made a decision to focus on end-of-life care.

Shearer sat with Apseloff for more than an hour, painstakingly reviewing the details of Isabel's care and medical status. Later, on her way home, Shearer hopped in her truck and paid a house call. She found Isabel peeking out from under Apseloff's bedsheets, bedraggled and frail, but feeling feisty enough to yowl a loud greeting. "Bea Arthur," Apseloff joked. The cat, a Siamese, allowed herself to be pulled from under the bedclothes without complaint and stood under her own strength on the bathroom countertop for a quick physical exam.

"You know, to me she looks dehydrated," Shearer said. Apseloff winced. It was time for another round of a subcutaneous dialysis, in which intravenous fluid is injected through the skin into the body cavity, to be absorbed by the capillaries and do the rehydrating and detoxing that is normally handled by the kidneys.

"Not my favorite thing," Apseloff said, as he and Shearer unwound sterile plastic tubing and unsheathed a hypodermic that would feed the liquid into Isabel from the scruff behind her neck. In the mirror, Apseloff's reflection was grim-faced, but the cat seemed revived. When the procedure was over, she walked easily downstairs to the living room and hopped up into her corner of the couch by the fireplace.

Shearer believes pet hospice could greatly reduce the high incidence of what vets call "economic euthanasia," where pet owners put animals to death simply because they can no longer afford to care for them. But the time and expense involved in providing hospice is considerable. (A first-time hospice visit costs $82 for a consultation and evaluation, about the same price as a regular, one-hour veterinary visit.) Shearer once envisioned hospice care as part of every veterinary practice but now thinks a central hospice that vets could refer clients to makes more sense. Her hospice recently received nonprofit status, and she is applying for grant money to assist low-income clients.

For some of her clients, hospice care meets needs that modern veterinary medicine does not.

"In my experience, compassion isn't much of the equation in the average veterinary practice anymore," Apseloff says. "It's more about client management than compassion. I've been to a lot of different vets over the years. Most places I see, they're businesses; they run people through. It's like doctors' offices. They're running people through, they're billing, they're making money. And hospice just doesn't fit into that for them. Anything that takes time doesn't fit into that for them."

BY JANUARY, Bear's back legs were weaker still. By late February, he needed help getting up much of the time. Thyroid supplements had raised his energy level, but the dosage was hard to get right. He was manic some days, lethargic the next. When the vet tested his reflexes by curling his paws under, he left them that way, as if he could no longer feel what was happening below his knees.

"That dog needs help!" a man in a van hollered as we inched along the sidewalk one evening.

"Thanks for the bulletin, Einstein," I thought. But the sarcasm was just a cover for the anguish I felt at not being able to help him.

The brain scan was negative, but after taking weeks to relay the radiologist's report confirming that, the neurologist no longer talked about a spinal tap. "We'll just keep him comfortable," he said. A third vet thought there might still be more diagnostic work to do -- a blood culture to check for a fungal infection, for example -- but this vet was in another state. I thought about piling Bear into the car, but hesitated, worried about the stress a new round of tests would inflict. And there was the cost. I knew one dog owner who'd run up a tab of $3,000 in one weekend at a university veterinary hospital, only to be given a diagnosis of "idiopathic." Translation: We don't know.

Bear was belatedly tested for Lyme disease, and the blood work came back positive, but the vet thought it unlikely that Lyme was the source of his problems. Antibiotics seemed to help at first, but then he deteriorated again.

Then events overtook us. On a Monday in early March, Bear began to run a high fever and suddenly could not take more than a few steps without help. The vet made a house call and gave an injection of a powerful antibiotic, and Bear improved for a few days. But by the end of the week, he was weak again and on Friday had to be carried to the clinic. X-rays to check for signs of cancer and other tests were inconclusive.

At the end of the visit, the vet proposed giving Bear an injection of one non-steroidal anti-inflammatory and a second, in pill form, to be started the next day.

"Um, aren't those dangerous?" I asked tentatively. I had only just heard that about the drugs' occasional side effects, and he seemed so sick. I was worried about putting more medicine on his plate.

"Not a problem," the vet said. "We'll only be using it for a week, and we'll be watching him closely."

The next day, however, the first pill caused immediate and severe gastric problems that continued through the weekend, although I stopped the pills immediately. By Monday night, Bear was panting and in pain. I called the vet clinic right before closing. How do you know when it's time to go to the dog emergency room? I asked. "Use your judgment," the vet tech said.

I spent Monday night lying on the floor next to Bear, spooning water into his mouth with a saucer. On Tuesday morning, the vet made another emergency house call. An appointment with an internist at a second specialty clinic for later in the week was moved up. The vet thought Bear's spleen looked distended. Have the internist check it with ultrasound, he said.

The spleen was fine, as it turned out, but the ultrasound revealed something much worse.

"Bingo," the internist said, returning to the exam room with a syringe of dark, plum-colored fluid pulled from Bear's gut. There was a hole in Bear's intestine, and the leak had caused a massive infection of the abdominal cavity. The hole had probably only opened a few days earlier. There were two options: operate immediately to close the hole and try to clean up the infection. Or, the doctor said, "I'm afraid we have to put him down."

Bear lay panting on the examining table between us. The doctor carefully outlined the risks and costs. The operation was major surgery. The anesthesia would be deeper and thus more dangerous than the brief sleep induced for the MRI. If Bear survived it, he would need at least two days in intensive care, followed by two weeks of convalescence and massive doses of antibiotics. The cost would be roughly $3,200.

Still, the internist added, softening his tone, he'd seen old dogs survive the surgery and recover very well. His own dog was one of them.

I looked at Bear. Though he was clearly in pain, his head was up and he was alert. It did not seem possible to give up on him. I stroked his head one last time and gave the go-ahead. They took him off to prepare for surgery.

I went outside to the pay phone and mapped out the rest of the evening: home to change soiled clothes and back again before the surgery started. Tomorrow, while Bear was still in intensive care, I'd clear out the stained rug pads that I'd been cleaning and re-cleaning and replace them with fresh ones. Family and friends would help with the nursing. I could manage it all. I could see it unfolding.

But Bear died on the operating table that night, before the surgeon made a single incision. He was weak from infection, and his heart did not tolerate the anesthesia, the vets said. For the same reason, the medicines used to stabilize adverse anesthetic reactions failed, too.

Shortly after they'd started the anesthesia, a nurse in surgical scrubs and a plastic shower cap had run into the little waiting room where I was staring at a fish tank. "He's having trouble with the anesthesia," she said, and asked if I would approve the use of CPR. I blinked. CPR?

Yes, she said. There would be a small charge for it.

Okay, I said, and the nurse raced out again. Much later, I wondered if what she'd really been asking was, "Is it okay to let him go?"

A few minutes later, the nurse came back and said Bear was gone. Doctors appeared. The emergency room vet, a woman, cried and said how sorry she was, which made me feel both better and worse, but mostly better. The internist walked me through what had happened. He took his time even though it was way past closing.

They'd done a quick autopsy, the internist said. The hole in Bear's gut was large enough to put your finger through. It looked as if the infection had been underway for a few days. There was no sign of cancer, or a sharp object, such as a piece of bone, that might have caused the hole. It was well below the place in the stomach where ulcerations from non-steroidal anti-inflammatories typically are seen, and, in any case, it seemed unlikely that two doses of the medicine could have been responsible. He couldn't rule it out, he said, but he really doubted it. Most likely, we'd never know what caused the hole.

They brought me Bear's collar and tags, and said they could make a cast of his paw print if I wanted. They explained they could dispose of the remains, or I could arrange for a cremation, in which case I'd have an urn with his ashes.

I asked if I could see him. A few minutes later a nurse led me into a small examining room, where they'd laid him on a pretty pink-and-white striped sheet. There was a blue surgical blanket covering his body up to his neck. His upside ear was cocked, as if he was listening. The top of his head was still warm. The hospital was very quiet. I thought about the golden retriever I'd seen earlier in the evening, a successful amputee dancing out of the clinic with his elated owner. Why couldn't that have been us?

It occurred to me that what I'd wanted all along from veterinary medicine was the best of both worlds: the commitment, skepticism and horse sense of an old-fashioned vet, and the compassion, diagnostic smarts and philosophical approach of the new breed, vets informed by the belief that animals, in effect, were people, too.

In the lobby, they handed me the paw print on a clipboard labeled "oncology." I couldn't think of what to do after that. I didn't want to go home, where the living room was strewn with the ruins of Bear's awful last days. I called my boyfriend and then my family to relay the news, then went to a club near my house and listened to a country band from Brooklyn, waiting.

When my boyfriend arrived, we went to my house and walked out into the back yard. It was strange to think we'd never see Bear nosing around in the grass again, sniffing the fence line. The squirrels would be happy he was gone. They'd noticed immediately when he'd begun slowing down, and soon were walking, not running, to the nearest tree when they saw him step gingerly down the back-porch ramp. Soon enough the feral cats, or the possums, or even the neighborhood red fox, would be angling for backyard supremacy. Within weeks, a family of raccoons would be emboldened to take up residence in the chimney.

There was a full moon that night. It cast a bright light over the grass and the hedges. In the sky, a dozen birds moved across the face of the moon in a bright white vee. They may have been geese heading north for the summer. Or possibly they were cranes, which also migrate north at that time of year. White cranes are a sign of luck in many parts of the world. So, in my head, I made them cranes and hoped they would bring Bear luck, wherever he was.

A few days later, a vase of flowers arrived on the front doorstep. There was a card. It was from the veterinary clinic.

"With sympathy for the loss of Bear," it said. "He will be missed."

Mary Battiata is a Magazine staff writer. She will be fielding questions and comments about this article at 1 p.m. Monday on washingtonpost.com/liveonline.