Did the drinking fountains at West Catholic High School dispense holy water?

That may explain the astonishing number of priests, nuns and religious brothers who have poured out of that urban brick fortress at Chestnut and 45th Streets - many of whom returned yesterday for a special reunion.

Since its founding as a boys' school in 1916, and the addition of the girls' school in 1926, West Catholic has turned out more than 1,000 religious sisters, 600 priests, at least 300 Christian Brothers, six bishops, and Cardinal John O'Connor, the late archbishop of New York - Class of '38.

That may be a record for any Catholic high school in America, according to West Catholic's president, Brother Timothy Ahern.

But the 180 cassocked and habited alumni who came for Mass and a light breakfast were having too much fun to solve the mystery of their great numbers.

"Are you a St. Joseph?" Sister Elizabeth Heller shouted above the din in the crowded library after the morning Mass. She meant a Sister of St. Joseph.

"No, I'm an RSM" - that's Religious Sisters of the Americas - answered Sister Kathleeen Waugh, who stuck out her hand in greeting.

"Betty Heller, Class of '54," said Heller, clasping Waugh's hand.

"Fifty," replied Waugh. In an instant, the two were laughing and reminiscing about their girlhoods at "West" a half-century ago.

Milling around them, clutching foam cups of coffee, doughnuts, and a few canes and walkers, were gaggles of SBSs, IHMs, OPs, OSFs and many more nuns, along with 14 priests, two deacons and a handful of CBs, or Christian Brothers, the school's male teaching order. (SBS is Sisters of the Blessed Sacrament; IHM is Immaculate Heart of Mary; OP is Order of Preachers-Dominican, and OSF is Order of Saint Francis.)

Yesterday's reunion was the idea of the Rev. David Engo, a Capuchin priest who arrived at West only last fall as the school's chaplain.

He and Ahern sent out invitations two months ago and were "amazed," Ahern said, when nearly 10 percent of all the school's religious graduates replied that they were coming.

While Ahern (Class of '66) knows of no national data confirming the school's bragging rights on vocations, he surmises that - miracles aside - the sheer volume of West graduates helps explain the high numbers.

In the 1950s - an era when many of yesterday's visiting alums were teenagers - West was one of the nation's largest Catholic high schools. Actually, it was two campuses, West Catholic for Girls and West Catholic for Boys, and in any given year each had about 3,000 students in grades 9-12.

But those numbers, like the school's vocation supply, are history.

The boys' and girls' schools merged in 1989 because of declining enrollment, and today West Catholic numbers just 561 pupils, only 52 percent of whom are Catholic.

"Only a few" have entered a seminary or convent in recent years, according to Ahern. Since 1995, he said, "none of our graduates has joined the Christian Brothers."

And so, while celebration was the theme of yesterday's joyful gathering, the call for Catholic vocations was its subtext.

The homilist at the Mass was Msgr. James T. McDonough (Class of '49), who told how the school's principal had stopped him in the hall one day and asked: "James, did you ever think of becoming a priest? I think you would be a good one."

In fact, McDonough said, he had been thinking about it since he was 4 or 5, when he had asked his mother who the man on the altar was.

"He's a priest," she said. "And you can be one too."

McDonough urged any students who felt called to religious life to "listen to that voice within, and respond."

"See how old we all are up here?" he joked, pointing to the other gray-haired priests at the auditorium altar, who laughed. "We need some of you to come along and take over."

Students hearing that call were hard to find yesterday.

"I never thought about it. I'm just helping out," said 15-year-old Franck Bikibili, who was wearing the black cassock and white surplice of an altar server and carrying a candle. "I'm going to be a soccer player."

Philip Cheung, 17, another server, said he had "thought about being a priest when I was about 14, but not so much now." He wants to be a doctor, he said.

But Bobby Nguyen, 18, of Southwest Philadelphia, said he was "thinking about" entering the priesthood. Growing up in Vietnam, he said, "the priests were always there for us." Being a priest, he said, "feels like a privilege."

"I don't think it's for me," Siobhan Richardson, 16, of Overbook Park, said of religious life.

Bridget McGovern, Class of '96 - and at 29 one of the youngest at the reception breakfast - said it was her time at West Catholic High that led her to be a candidate for the Sisters of St. Joseph.

Her journey into religious life began, she said, when she told an acquaintance that she had gone to West Catholic. "She said: 'Oh, West Catholic: They always served the poor.' "

"That got me thinking about the idea of service," said McGovern, who plans on taking vows in a a few years.

It was a time of retrospection and fond memories for most of the nuns, some of whom wandered down halls they had not seen in decades.

"Oh, the elevator hasn't changed," said one.

"They never let us on it," joked another.

"Are we allowed on these stairs?" asked one elderly nun, stepping cautiously on the main marble staircase that had been restricted in her day to upperclassmen.

"It's OK," one of her friends called out. "You're a senior."

Contact staff writer David O'Reilly at 215-854-5723 or doreilly@phillynews.com.