The discovery that bacteria caused disease, a revelation that came in the mid-nineteenth century, brought about a sea change in hygiene and public health. To control germs, experts said it was mandatory to wash hands regularly. In addition, to avoid disease, sewage had to be disposed of safely, and water had to be pure. Meeting these goals, a challenging undertaking, continues to this day. In the quest for better hygiene, science and technology elucidated the importance of new and better ways to promote health. Even relatively simple inventions, like the flush toilet and chlorinated water, have probably saved millions of lives. Washing machines and detergents play a big role too—they helped people clean clothes quickly and thoroughly. In the struggle to prevent bacterial diseases, modern society has clearly gone the extra mile. Hygeia would be pleased, for although she is no longer worshipped as a goddess, people today are cleaner than ever.