During San Francisco's 1967 summer of love, Oregon artist Phyllis Brown lived just a few blocks from the city's patchouli-drenched Haight-Ashbury district. But she secretly hoarded a bottle of ultra-establishment White Shoulders perfume. Decades later, a drift of the scent still evokes a bizarre episode in her life.

"I was sharing an apartment with a wild girl named Kitty and her 2-year-old daughter, Jennifer," recalls Brown. "I kept my White Shoulders in this sewing tin, but one day Jennifer found it and spilled it all over everything. Everything reeked of White Shoulders, and I got really mad. A few weeks later, Kitty and Jennifer didn't come home one night. The next morning my landlord showed me Kitty's picture on the front page of the San Francisco Chronicle. She'd gotten stoned on acid in Golden Gate Park and forgotten about Jennifer, who wandered to a police station. The cops found Kitty in the park."

When Brown smells White Shoulders now, the distinctive floral aroma unsettles her. "I think of that sewing box, and of Jennifer, and of Kitty's picture in the paper."

This power of fragrance to evoke the past has been noted by poets, studied by scientists and cashed in on by Madison Avenue. But why should a simple scent give us such a powerful blast of who, where and how we were years before?

Searching for clues to this riddle, experimental psychologist Rachel Herz of Philadelphia's Monell Chemical Senses Center has for a decade investigated the relationship between fragrance and memory.

Herz says scent-induced memories may have such an instant impact because the sense of smell connects more directly than any of the other senses into the brain's limbic system--the part that organizes emotions and memory.

"Memories brought back by odors are experienced in a much more emotionally potent way than those from other sensory cues," says Herz. "In a most basic and most primitive way, smells tell us what to approach and what to avoid."

Such associations may affect us more profoundly than we realize. In a recent Monell study, children were asked to solve a deliberately frustrating maze in the presence of a distinctive odor. When the same group of children were subsequently given an unrelated task--some in settings with the original odor, others not--the worst performers were the ones being tested in the environment laced with the frustration-linked smell. By the same token, smells can transport us "across thousands of miles and all the years we have lived," as Helen Keller wrote.

For Connecticut antiques dealer Babs Seymour, the fragrance of an old dime store perfume called Blue Waltz seems to have almost a "fountain of youth" effect, mystically evoking her adolescence in 1950s Marysville, Calif. It was in Marysville that her military family stayed long enough for her to establish a beloved group of friends, and "we all wore Blue Waltz," says Seymour of the vanilla-ish fragrance she describes as "sort of a subdued, spicy smell that has the sea in it, a sweet ocean smell."

"My best friend, Josephine Carmen Vigil, introduced me to it," says Seymour. "I was kind of a tomboy and she was determined to make a lady out of me. Every morning I'd go over to her house and we'd get ready for school together. We'd fix our hair and makeup, and put on our Blue Waltz."

Though Herz says such perfume-linked memories may be intensely felt, she adds that there's no evidence that memories evoked by fragrances are more accurate than those triggered by other sensory stimuli. But one of her studies suggests that when it comes to mate selection, the smell of a man matters more to a woman than hers does to a man, and other research indicates that women are more attuned to odors.

Herz theorizes that female sensitivity to male smells may be a species-fostering trait, with women instinctively ensuring the health of future offspring by literally smelling out potential mates with antibodies different from their own--which possibly would produce offspring with a healthy diversity of physical defenses.

This heightened female sensitivity to fragrances may explain why many women yearn nostalgically for fragrances that connect them with happy memories and so few men seem to be pining for a whiff of High Karate or Wild Rhino.

"Jade East was the favorite of the 'plasterers,' " says Brown, referring to a popular mid-1960s male scent. "It had a chemical, bitter, citrusy, loud smell. It screamed 'Smell me, here I am!' " The same era featured an equally intense male fragrance called English Leather, symbolic of the period's fetish for all things British.

"I was in junior high school in Beltsville back in the Beatles era, when the Carnaby Street thing was really popular, and there was a Yardley cologne called Oh! de London," says one nostalgic Maryland suburbanite. "I still remember it and wish I could find it. It had kind of a light jasmine fragrance. It was during that 'mod' time. It was part of my whole mod look--my Empire-waist dress and my black patterned stockings and my ironed hair."

This longing for remembered fragrances gave veteran New York perfumer Jeffrey Dame the idea of reviving discontinued scents familiar to baby boomers and their mothers and aunts. He researched arcane perfume journals for the original recipes of such out-of-commission perfumes as Blue Waltz, Ecusson, Apple Blossom, Casaque and others, secured necessary legal rights, then set out to re-create them. Sometimes he had to find substitutes for old ingredients now banned from use.

His totally Web-based business at longlostperfume.com features about a dozen scents--including a male cologne called the Baron--and he's planning to resurrect 20 more lost fragrances soon.

Dame says that when a perfume conjures a memory, "you may go straight back to the prom in 1954. But not only do you remember the prom, you're remembering the car you rode to the prom in and the texture of your date's jacket."

He says those searching for particular scents tend to be the women who wore them and the daughters of women who wore them and recall having to "sneak a spray" of perfume from their mothers' atomizers. But he also believes that liking or disliking fragrance is something you're born with, a personal thing--a God-given set of genes that says "you're going to like to wear fragrance or you're not."

For women who do like perfume, happy scent memories seem to be pleasantly associated with first kisses, first dates and young love. Science writer Elaine Friebele of Cheverly says the smell of Wind Song evokes the excitement of getting ready for a high school dance as a North Carolina teenager.

"It smelled like the unknown," she says. "It was just a very romantic fragrance."

But sometimes the date evoked by a particular scent may not be one you want to revisit. Patricia Butler of Potomac can't tolerate Polo cologne thanks to a particularly obnoxious guy she once knew.

"I hate the smell of it because a real schmuck with a capital S used to wear it, and every time I smell it I just cringe, really. It's almost a physical reaction."

Certain scents may also remind us of old selves we'd rather forget.

"Back around 1970 the fragrance of musk was popular as an essential oil," says Phyllis Brown. "I thought it was so sexy and I just loved it. But then the hippie thing ended very abruptly and painfully for me, and the smell--I just couldn't stand it. To this day when I smell women in their forties and fifties who still wear it, I think of them as throwbacks. I think, 'There's some woman who wants to be a chick.' I actually believed we were chicks."

Fragrances can also conjure lost loved ones in dramatic ways.

For National Institutes of Health writer Susan Cahill, Aqua Velva instantly evokes 1950s memories of her late father's morning shaving ritual.

But it's the memory of an older sister's Pond's Dreamflower talcum powder that most calls to her. "If I could find it now somewhere, I'd buy barrels of it," she says. "It was wonderful."

Babs Seymour knows the feeling. Blue Waltz vanished from the nation's Woolworth stores sometime in the late 1950s or early 1960s. For years she scoured yard sales in search of a residual drop or two left in its heart-shaped bottle. When she finally found Jeffrey Dames' Internet site, she was ecstatic.

Wearing it "kind of brings back a time when you're a kid and just beginning to notice boys," she says. "We all wore Blue Waltz."

It also revives another blissful memory.

"When Damon Casmey kissed me on the cheek, I was wearing Blue Waltz."

CAPTION: "Evening in Paris," watercolor of perfume bottles on a windowsill.