- Handout 1: “Information About Cholera”
- Handout 2: “Map of Cholera Deaths”
- Handout 3: “Map of Cholera Deaths and Locations of Water Pumps”

Objectives
Students are expected to:

Opening the Lesson
Have students use atlases to locate Great Britain and London. Tell students that in September 1854, during the last great cholera epidemic in Great Britain, 500 people—all from the same section of London, England—died of the disease within a ten-day period. Bacteria were still unknown. People were panicking. Distribute or read Handout 1 to students.

Developing the Lesson
Dr. John Snow was a British doctor who had been studying cholera for many years. In trying to determine the source of cholera, Dr. Snow located every cholera death in the Soho district of London by marking the location of the home of each victim with a dot on a map. Distribute the handout “Map of Cholera Deaths” and have students focus on the spatial distribution of cholera deaths.

Have students formulate questions about the map. (For example, why is there a cluster of deaths near Broad Street? Why are there fewer deaths on Regent Street?) Ask students to speculate as to the spread of cholera deaths. Have students predict the location of pumps. Record student responses on the chalkboard. After discussing the distribution of cholera deaths, distribute Handout 3, “Map of Cholera Deaths and Locations of Water Pumps.” Ask students to formulate additional questions—for example, why were there so many deaths near Broad Street? (Explain to students that water pumps were the only source of drinking water.)

Concluding the Lesson
Ask students what course of action they would take if they were city officials presented with the information on Dr. Snow’s map. Then tell students that Dr. Snow requested city officials to remove the handle from the Broad Street pump, making it impossible to get water there. After his request was granted, the number of new cholera cases in the area declined dramatically—almost to zero. Dr. Snow’s theory was confirmed: Cholera was associated with the drinking water supply, and the water was carrying the disease to its victims.

Assessing Student Learning
Ask students to list the steps that Dr. Snow took in solving the cholera problem in London. Ask them to answer these questions: What if the locations of deaths and locations of water pumps (Handout 3) were not clustered? How might this have altered Dr. Snow’s research and course of action? Have students identify particular problems and issues that might be better understood through map development and analysis—for example, the occurrence of auto accidents, tornadoes, earthquakes, or crimes.

Extending the Lesson
Discuss some questions that are important to medical geographers: Where are diseases found? How do diseases spread? Is there a pattern to the spread of disease? Are some diseases more common in some environments than in others? Are the locations of health-care facilities important? Are they related to patterns of disease?

Have students research the spread of specific diseases, for example, AIDS, smallpox, malaria, or typhoid, then use medical atlases to research and plot the spread of diseases on blank outline maps.

Give students (or have them acquire) information on traffic accidents in your community. (This information should be available from local police or the county sheriff’s office.) Plot the accidents on a map and have students formulate questions and draw conclusions based on the data. Perhaps there is a need for a stop sign, traffic signal, or lower speed limit in a particular area.

Additional Reading
Snow, John. Snow on Cholera. New York: Hafner, 1965.

This lesson from TC Tool Kit: A Resource for Teacher-Consultants, National Geographic Society, 1993.