When Cities Were Cesspools of Disease | Nat Geo Explores

Imagine living in darkness. You're in a roof the size of a closet with your entire family. I can't see a thing, but you can hear and smell everything—every breath, every sneeze, every cough that hits your face. This is life in a 19th-century city.

There's a story of 19th-century American history which is about progress—the rise of America to becoming a great economic power. But there's a pretty grim underbelly to that story, and that is a really shocking rate of death to infectious diseases. America in the 1700s was, to a large extent, a country of hamlets and villages and small towns, with a few cities which were slowly growing. Come the 1800s, cities like Boston and New York were doubling and doubling again. Technological innovation was thriving; titans of business like Rockefeller and Carnegie were growing industries at unprecedented rates. Railroads were transporting people and things faster; machines were making things more efficiently than humans ever had in history. This was quite literally a revolution. Tons of new jobs were created.

But here's the thing: the cities weren't ready for all those people. So places like New York City ended up packing these newcomers into cheap apartments or tenements. They were small and rarely had windows, so there was no light or ventilation. Houses were overcrowded. They were working in factories, breathing on one another, contaminating one another with their germs and also with feces. That's right—feces. That's because there weren't proper sanitation or sewer systems or clean water supplies. Very rapidly, people were starting to drink water that contained feces from their neighbors, through a number of diseases that claimed a lot of lives. The most serious were respiratory illnesses, and the biggest killer of all was tuberculosis. Tuberculosis killed one in seven in the United States.

In Europe at this point, people came to suspect that their living conditions influenced their health. They began to argue that if you want to combat diseases, you've simply got to clean up the slum areas. In fact, in New York in the 1830s, they had people sweep the streets. They called this the “Helle beam dump” decades, and they were amazed to find that underneath all the muck and the film and the decomposing animal bodies, the rattling cobblestones— they were all doing this because they believed in miasmas. These gases that rise up from decomposing matter, they believed somehow cause sickness.

But the efforts to clean cities got a major push in the late 19th century when doctors and scientists were able to prove that diseases were not caused by miasmas but by germs. One of those doctors was Robert Koch. Robert Koch was a German general practitioner who, in his spare time when not treating patients, devoted endless hours to investigating disease under the microscope. He discovered that specific germs caused specific diseases, but he's probably best known for his work in tuberculosis. He discovered the germ responsible and found that it was transmitted through the air.

Now that people realized what causes infectious disease, they had every incentive to make sure that people had clean water. When you wash your hands, you wash away many of the disease-carrying smudges you may have picked up, and they had sewage pipes to take away the effluence. This led to large-scale civil engineering projects across America. Due to the improved access to clean water, in the first few decades of the 20th century, US cities saw an estimated 50% drop in mortalities. Laws were also passed to reform housing in the cities to ensure residents had sufficient light and proper ventilation in their homes.

In less than 20 years, the death rate from tuberculosis plummeted from one out of every seven to more like one in 1,000 in the United States. Robert Koch even got a Nobel Prize for the impact of his tuberculosis research. Life generally was getting better and better for Americans. Knowing that germs cause disease was a significant component of that.