Twenty years ago, Bill Jacobs made the tuberculosis bug glow. It was like mounting a pair of headlights on a man-eating tiger. One of the world’s deadliest infectious diseases could no longer slink around in the shadows, evading its trackers. Microbiologists could now peer into a microscope to see if a particular antibiotic turned out the lights—that is, killed the TB bacteria. Or at least they could do this so long as they didn’t happen to be Bill Jacobs. That’s because when Bill Jacobs looked into the microscope at his own creation, he couldn’t see a thing. He was going blind.