Not a drop of Portuguese blood flows in Barbara Humber's veins. Her ancestry is Scottish and Irish, but hand her a pile of linguica, garlic and potatoes, and she can cook up a genuine batch of sopa.

Ms. Humber is just one of a growing number of Islanders who have not only joined the Portuguese-American Club in Oak Bluffs but now play pivotal roles in it despite a glaring deficit: They aren't Portuguese-Americans.

The reasons aren't really that complicated.

Ms. Humber, a bookkeeper from Oak Bluffs and now one of the lead soupmakers for the annual Feast of the Holy Ghost, joined four years ago because she was impressed with the good deeds accomplished by the club - ranging from tens of thousands of scholarship dollars given away each year to Vineyard high school students to the work with Camp Safe Haven, a camp for children with AIDS.

"They're the one club you hear the most about, and the one that does the most," she said. "They don't care if you're Portuguese or not. Whatever you need done, they do."

For Dave Greenlaw, the reason for joining wasn't quite so altruistic. It was purely social. "I was friends with a group of people who played darts over here," he said.

Then he married a woman who was an active member. Now, Mr. Greenlaw is the PA Club manager. "And I'm Scottish, Greek and French," he said.

How about speaking Portuguese? "The language?" he said. "No."

It's been almost two decades since the PA Club required proof of Portuguese lineage for membership. Now, all you need is $35 for an official club card.

"We wouldn't have much of a club if it was only Portuguese," said Tricia Bergeron, who can trace her roots back four generations to San Miguel and who has organized the feast for the last 14 years.

The PA Club was forced to open its doors to outsiders when it applied for non-profit status and had to comply with federal laws banning discrimination in the 1980s.

But the change has helped swell the ranks of club members. "Ten years ago, there were only 300 or 400 members, if that," said Ms. Bergeron.

This weekend's feast comes at a time when the PA Club is in the midst of constructing a new clubhouse off the backside of the present building. Mr. Greenlaw speculated that the new building could also account for a resurgence in the membership rolls.

"It's not just Uncle Joe's basement anymore," he said.

While the club has drawn in Islanders from varied ethnic groups, it hasn't attracted the one group with real ties to both the history and language of Portugal: the Brazilians on the Vineyard.

"That really surprised me," said Ms. Bergeron.

"It's exciting that the Brazilians are here, but they feel separate from us," said Jean Andrews of Edgartown.

Indeed, it wouldn't be hard to argue that the non-Portuguese influence at the PA Club is simply more dominant.

Kay Manning, another non-Portuguese member of the club, pointed out that for almost eight years, not even the club president was Portuguese.

"They've got a whole league of nations, and it's great," she said. "The old-timers are all passing on . . . We've got them outnumbered at this point."

Mrs. Andrews agreed. "We've become diluted into the milieu of the Island," she said.

But are there any misgivings or hard-feelings about a membership where the blood-lines are so thinned-out?

"A lot of the old Portuguese are wistful for the good-old-days," said Mr. Greenlaw. "I knew I had a huge bridge to cross with the older members. But they universally accepted me, and it was a great relief."

Ms. Manning, pointing out her Scottish roots, said she remembers when she first started going to the PA Club with Joe Nunes (one of the oldest and most honored club members) and then became club secretary. "It turned a few heads."

Now, she said, "The old-timers just roll with the punches."

But in the face of so many new faces, holding onto the Portuguese heritage is key. "So much of the culture is lost," said Ms. Bergeron. "The few Portuguese that are left certainly do want the tradition carried on."

The Holy Ghost Feast that starts tomorrow at the PA Club grounds on Vineyard avenue embodies that link to the past. It's more than a parade, more than the food and the entertainment and games.

It starts with the preparations, the women who began Monday cracking dozens of eggs and blending them with flour to make the dough for malasadas, a fried dough.

"I could probably do it in my sleep," said Melanie daRosa, a fourth generation Portuguese-American who lives in Oak Bluffs. She expects to make more than 20 batches which requires almost 90 eggs and at least 80 cups of flour.

"It's so sticky, there are times that it's oozed right out of my refrigerator," said Mrs. daRosa.

Today, the soup fixings will arrive from New Bedford: 250 pounds of linguica, 150 pounds of chourico and 160 pounds of cacila, a Portuguese-seasoned pork, plus at least ten bags of onions, cabbage and beans.

Ms. Bergeron's 8-year-old son is already steeped in the tradition. "Mom, order extra chourico for me," he said as he sat at the PA Club Wednesday watching her keep track of the details involved in planning the festival.

Traditions rank high in Ms. Bergeron's preparations. She has brought back the Portuguese Folklore Dancers for Sunday, and invited Portuguese-American clubs from Taunton and Fall River to attend.

An old photograph she fetched from a shelf in the club shows a feast from 1927 when PA Clubs from Peabody and Hudson arrived on the Island bearing banners. The photograph, almost a foot and a half across, displays a sea of people.

Saturday, people will also come to see the auctions, music by the Stingrays and Lenny Baker. On Sunday the soup is free, harking back to the genesis of the feast when a generous queen brought soup to the poor despite the king's forbiddance.

And even if your bowl of soup wasn't made by a Portuguese-American, rest assured that the cooks were well-schooled. "We did what we were told," said Ms. Humber. "The older ones tell you, and you have to make it the right way."