Let a voice come from your streets, alleys, courts, workshops and houses that shall startle the ear of the public, and command the atention of the Legislature. 1848 Public Health Act is passed by a reluctant Parliament fearful of spread of cholera. National Board of Health and local boards to regulate water supply, sewerage, offensive trades. Smoke abatement becomes a political responsibility of the health department. 1852 Mother of the Forest giant sequoia tree chopped down in Calaveras Grove of Big Trees in what would become Yellowstone National Park.
Public opinion is aroused.
1854 Henry David Thoreau writes Walden. 1854 John Snow, London doctor, maps spread of cholera in Broad Street neighborhood, traces cases to a contaminated drinking water pump. 1855 First comprehensive city sewer plan in U.S. in Chicago. By 1905, all U.S. towns with population over 4,000 have city sewers. Baltimore sewer system, begun 1915, last city to build comprehensive system.