What English physician was able to influence public health improvements?
1854 Broad Street cholera outbreak:  This outbreak, which killed 616 people, is best known for the physician John Snow's study of its causes and his hypothesis that contaminated water, not air, was the source of cholera. 1854 Broad Street cholera outbreak:  This discovery came to influence public health and the construction of improved sanitation facilities beginning in the mid-19th century.
i don't know