By Harold Pollack I spent yesterday at Cook County Jail, a behemoth complex of buildings the size of a small neighborhood on Chicago’s west side. During a glacial wait for some Xerox copies, I stared out the window at the sidewalks marked off by high fences and ugly concertina wire. Young moms, kids in tow, tentatively pushed baby strollers along this maze of concrete walkways leading to the visiting area. Out of sight, out of mind, prisoners are a population we readily ignore when the cable TV shows are off. Yet these men and women are absolutely central to public health.