Today in History—March 24: The Lecture That Unraveled the Mystery of Tuberculosis
On this day in 1882, German physician Robert Koch gave a lecture at the monthly meeting of the Berlin Physiological Society announcing that he had discovered the cause of tuberculosis: the tuberculosis bacterium.
That sounds like a well, duh, now. But that night, the shy, usually hesitant man spoke clearly as he turned medicine, microbiology, and public health on their heads.
He’d isolated it and grown it in his lab, he said calmly—as if he hadn’t just made history.
To get there, Koch first had to overcome two dominant ideas: spontaneous generation—the idea that living things could develop from nonliving things (maggots, for example, were supposedly produced by rotting meat) and miasmatic theory, which blamed disease on “bad air.”
In 1876, researching anthrax with the clever use of glass slides to view bacteria under a microscope, Koch showed for the first time that a specific pathogen could cause a specific disease. This idea—germ theory—wasn’t new, but no one had ever proven it.
Then came years of travel to investigate cholera outbreaks in Egypt and India, where he correctly identified contaminated water.
Only then could he tackle tuberculosis—aka consumption or the white death. Rapid industrialization and crowded cities meant it accounted for 1 of every 7 deaths in the U.S. and Europe.
Tuberculosis had been known for thousands of years. It was thought to be hereditary, since it affected family members. But Koch suspected otherwise.
In 1800s America some people blamed tuberculosis on vampires, so some victims were beheaded, buried upside down, or had their hearts burned to stop them from “returning.”
He worked in secret for months until he’d isolated and cultivated the bacteria. At the meeting he showed dyed tissue samples of bacteria he’d grown, and a few weeks later he published his findings. That work still underpins how we link microorganisms with diseases today.
He got some things wrong, notably insisting that tuberculosis in cows was unrelated. But in the larger sense, he was spectacularly right. His methods spread worldwide and transformed diagnosis and treatment.
In the years that followed, Koch continued in public health: He steered Hamburg through a cholera outbreak, studied leprosy, malaria, and tropical diseases—though some of his work on the latter involved ethically indefensible human experiments—and continued his fight against the disease he’d identified.
What Koch left behind was a blueprint for scientific investigation, and scientists have been following it ever since.
- 270: Koch’s unsuccessful attempts to identify the tuberculosis bacillus
- ~80: Attendees at Koch’s lecture
- 9,000 years: Oldest traces of tuberculosis germs found by archaeologists in human remains
- 1603: James I inherits the throne of England from Queen Elizabeth I
- 1934: U.S. Pres. Franklin Delano Roosevelt signs a bill for eventual Philippine independence
- 1958: Elvis Presley is inducted into the U.S. Army
