Returning directly from foreign battlefields, soldiers instantly hug and kiss their loved ones in almost all war movies. I won't blame filmmakers who can't wait to produce dramatic effects. In real life, though, homeward-bound soldiers have to be quarantined as a matter of protocol. The reason? Foreign wars, foreign diseases. It seems common sense. Yet, it was not commonly accepted, much less practiced, until William Crawford Gorgas became the surgeon general of the U.S. Army in 1914, the year World War I broke out.

Gorgas had a sharp eye for infection-related statistics. Today, even first-year medical students are quite statistically-minded. In Gorgas's days, however, not too many medical practitioners or researchers cared. They should. Statistics is a mathematical study of history. Yes, history. In modern times, a good medical professional is also a good medical historian. History prompts us to find out what happened and why. Statistics is a handy tool in this regard.

In terms of statistics, the following historical facts caught Gorgas's attention: 

The Crimean War (1853-1856) -- Britain, France, and Russia received not only returning soldiers but also their cholera.

The Franco-Prussian War (1870-1871) -- Prussia (and Germany at large) embraced victorious homecoming soldiers with smallpox.

The Spanish-American War (1898) -- American soldiers carrying typhoid hugged and kissed American civilians.

Also, in the American Civil War (1861-1865), the North and the South traded typhoid, dysentery, and smallpox.

Gorgas did not often have good statistical compilations to work with. But he was still able to delineate story-telling trends from them. What we take for granted in our age of algorithms was no mean feat in Gorgas's time. Indeed, WWI statistics turned out to agree with Gorgas that influenza killed more American soldiers than combat did.* His insistence on quarantine thus made every medical sense, though under-appreciated by his superiors who would live to regret it.

* Haskell County, Kansas, USA, was likely the ground zero of the 1918 influenza which went global. Spanish flu is a misnomer. During WWI American soldiers could pick up the disease in their home country or Europe. 

Author: Lingyang Jiang