Dirt and Disease. Population growth, urbanization, and industrialization vastly increased health problems in Europe between 1750 and 1914. Dirt from coal smoke darkened buildings and their surroundings, already muddy from unpaved streets. Crowding exacerbated sanitation problems in the cities and industrial districts. Coal fumes joined the smells of garbage and human and animal waste, which littered the streets, particularly in poorer areas, and contaminated the drinking water, already in short supply in most cities. Disease preyed on malnourished urban populations, leading to spectacular declines in life expectancy among the lower classes, especially during catastrophic natural disasters such as the European Potato Blight of the late 1840s. In 1840 in Manchester, England, high rates of infant mortality lowered the average life span among the working class to only seventeen years, whereas the average for all England was forty years. Scientists were slow...