Throughout the evening, an eclectic assortment of people--from purple-haired teenagers in leather to old men--stop by asking for hot chocolate, or for a sandwich, or just to say hello. Often the volunteers greet the people by name.

The sense of community among homeless youths that the mobile medical van has been quietly building for 30 years, Melchiono says, is just as important as the medical service the van offers.

He remembers when a homeless adolescent girl was hit by a car and killed. "We all had a memorial service for her, and I remember thinking that this is a girl with no family, but her family--her family of choice--came. I thought, what a wonderful example of a group of young people coming together to share their memories. I was touched."

An Intricate History

The medical van is just one service provided by Bridge Over Troubled Waters, a Boston-based organization established in 1970 to serve runaways and homeless youths. While the program targets people ages 14 through 25, the van does not turn away older people who need medical care.

The entire organization grew out of one book-mobile turned mobile medical van, which made regular stops anywhere homeless youths were known to congregate. The van was the first of its kind, and its success inspired activists nationwide to follow suit.

Today, the van is staffed solely by volunteers like Melchiono, who says he heard about the program 17 years ago and fell in love with it. He ran the medical van during the '80s and has been volunteering his time in addition to his regular job as a nurse practitioner with Children's Hospital in Boston ever since.

During their hour-long stay in the Square, the volunteers routinely see anywhere from three to 30 patients. Visitors are more numerous in the summer due to the general increase in Square foot traffic.