For Chinese immigrant Wong Chut King, surviving in San Francisco meant a life in the shadows. His passing on March 6, 1900, would have been unremarkable if a city health officer hadn't noticed a swollen black lymph node on his groin--a sign of bubonic plague. Empowered by racist pseudoscience, officials rushed to quarantine Chinatown while doctors examined Wong's tissue for telltale bacteria. If the devastating disease was not contained, San Francisco...