Boston, MA 11/16/11 Barney J. Brawer (cq), principal of the Michael J. Perkins School (cq), talks about the underchosen elementary school in South Boston, that is also a high achiever on the 3rd-grade MCAS. He gives The Boston Globe a tour, on Wednesday, November 16, 2011. (Pat Greenhouse/Globe Staff); Reporter: Vaznis; Section: Metro; Slug: XXX