One of our favorite stories to illustrate the power of information is chronicled in Steven Johnson’s The Ghost Map. The book is about a cholera outbreak in 1854 London and the impact it had on society, city life, medicine, and science in general. It reads like a medical thriller, and the historical account alone makes it worth picking up. But the true strength of the story is the insight it gives into the conditions needed for true multidisciplinary thinking.

John Snow and the 1854 cholera outbreak in London

19th century London smelled really, really bad. There was no working sanitation system, and people had cesspools underneath their houses. Physicians thought the foul air was responsible for spreading deceases, which made the government dump all the waste in the river Thames. This decision made matters worse. More cholera outbreaks occurred than ever before, killing hundreds of people at a time.

John Snow, a local doctor in London, was arguing for years that the evidence for the foul air theory was too slim, but nobody believed him. When Soho got struck with a terribly lethal outbreak on August 31 in 1854, he saw a chance to investigate it. Together with Reverend Whitehead, a man with strong community ties, he started to thoroughly question people in the Soho area. He asked them about the people they knew who got sick: where they drank their water, what they drank besides water, what they had to eat, and where they had died. The results from the interviews made clear that everyone who died during the outbreak drank from the water pump on Broad Street.

To strengthen his claim, John Snow made a spot map where he visualized the connection between the location of deaths and the location of the water pump.

This map represents a breakthrough in health geography, and can be regarded as the founding event of epidemiology. Snow’s methods were unusual in many aspects: maps were almost never used for anything else then navigation at the time, and the idea of collecting demographic information when it comes to epidemics was unusual. John Snow had the courage to collect and combine unusual kinds of information in unusual ways.

What have we gained since 1854?

Let us step back and look at the steps that were necessary to reach the important insights that ultimately saved many lives. First, Snow had crucial data about every death that occurred due to cholera. Then, Snow had the insight to visualize every incident on a map of London, which immediately showed that most incidents were clustered around a specific location. Finally, he combined the data on the map with information on the location of water sources around London. All these steps brought him closer to proof that the disease was indeed spread by specific sources of water, which could then be shut down immediately.

John Snow already had strong suspicions, but still needed to rule out that the outbreak didn’t have another source. He needed to play around with his data and visualize it to make a stronger case. Making it easier to work with collections of information is crucial for multidisciplinary thinking, and paves the way for unexpected discoveries.

At Silk, we are trying to create a better tool for working with different sources of data. If there ever were to be another John Snow, we want to make his life easier. To try Silk, go to our homepage and create a free account.