miasma theory | Sovereign Hill Education Blog

How did we get from Miasma Theory to Germ Theory in the 19th century?

The way we see the world, and ourselves in it, can completely change when new scientific theories/ideas come along. While this can be scary in the eyes of some people, for others it provides better ways of living, and exciting new opportunities to make money. Some examples of big ideas in science which have changed the world include:

The theory of evolution by natural selection, made famous by explorer and naturalist Charles Darwin in his 1859 book called ‘On the Origin of Species’. He explained that life on Earth has evolved (changed) over time as conditions (weather etc.) have changed, and as a result of the competition for resources (like food and water).
Medical technologies like anaesthetics (to make you go to sleep and feel no pain), antiseptics (to keep wounds and medical tools clean), antibiotics (to kill bacteria which cause painful and often deadly infections), and vaccinations (making us immune to certain diseases).
Understanding the role humans can play in the ‘Greenhouse Effect’ – if we put CO2 (carbon dioxide) into the air by burning fossil fuels like coal, natural gas, and petroleum (used to make plastics and fuels for cars) this can cause the atmosphere to heat up and change the climate.

Scanning electron microscope image of Vibrio Cholerae. This is the bacterium (germ) that causes cholera, a big killer on the 19th century Victorian goldfields. Reproduced from Wikipedia Commons.

In this blogpost, we will explore the scientific idea that microscopic germs exist, and how this idea radically changed the way we treat disease and deal with human waste. We are interested in this topic at Sovereign Hill Education because the 19th century gold rushes in Victoria were happening at the same time Germ Theory became popular. It changed the way Ballarat’s doctors did their work, and is the reason sewage pipes (that Ballaratians still use today) were installed under our city.

What is Miasma Theory?

Miasma = from the Ancient Greek word for ‘pollution’.

For thousands of years, people (and their doctors) in many places around the world believed that diseases, especially epidemics (like the Black Plague), were caused by ‘bad air’ which was commonly called miasma in English-speaking countries. It was thought that breathing-in or being too physically close to bad air from rotting organic matter (like a compost heap or pile of dog poo) could cause the four liquids found in your body (blood, phlegm [like snot], yellow bile, and black bile) to get out of balance. People believed that the weather and seasons could also affect these liquids and cause sickness (click here to learn more about a related idea called Humorism). Miasma was thought to cause all kinds of diseases, from diarrhoea to chicken pox, from the flu to obesity!

A representation by Robert Seymour of the cholera epidemic of the 19th century depicts the spread of the disease in the form of deadly air (miasma). Reproduced from Wikipedia Commons.

Staying away from rotting and smelly things is smart because they can cause disease, so those miasma believers were on the right track, but it’s not the smell of these things that actually makes people sick.

In the past, when doctors treated sick people based on this theory, treatments often involved draining some of their blood. We now know that such treatments could be more dangerous than the sicknesses they were treating – for example, in 1799 it is likely that George Washington was accidentally bled to death by his doctor while being treated for a throat infection!

What is Germ Theory?

Germ = Late Middle English word (from an Old French word, originally from Latin) germen, which means ‘seed, sprout’.

While the compound microscope (from the Ancient Greek for ‘small’ [mikros] and ‘to see’ [skopein]) was invented in the 1600s, it wasn’t until the 1800s that people realised they could actually see (through Lister’s improved microscope design) that germs – also known as microorganisms – existed, and could cause disease in people, animals and plants. A number of people had already tried to replace Miasma Theory with Germ Theory, but it took the work of scientists like Louis Pasteur and John Snow in the 1850s to popularise the idea that germs caused most diseases. Support for Miasma Theory didn’t completely disappear until the 1880s because, like any new scientific idea, it took a while to catch on. And unsurprisingly, people found it hard to believe in something they couldn’t see, until the technology came along to help them see it!

The first doctor on record (named Ignaz Semmelweis) to suggest that doctors should wash their hands between patients to avoid spreading disease was completely ignored by other doctors … He eventually died in an lunatic asylum from a disease he could have avoided if only his doctor had washed his hands!! There are many scientific ideas through history which people laughed at, or ignored, which turned out to be true. You can explore some of the most fascinating ones here.

How did these changes to the way we understand disease change our lives?

S.T.Gill’s Butcher’s Shamble, 1852, shows the unclean conditions in which meat was bought and sold before the popularisation of Germ Theory and the invention of electricity (to enable refrigeration)

By the time Germ Theory became popular, the Victorian gold rushes were well underway. In other parts of the world, the Industrial Revolution was creating factories around which cities were growing. Such hives of human activity like a mining centre or industrial city pushed people closer together than they had probably ever lived before in all of human history – and of course this meant diseases could spread more easily than ever from person to person. Knowledge of Germ Theory and the medicines it made possible over the next 100 years helped cure many diseases, but most importantly it helped to create more sanitary conditions, which meant people started living in cleaner houses and communities. For the first time, we started washing our hands thoroughly after going to the toilet, sterilising surgical equipment and removing and treating our sewage to make sure it didn’t end up in our drinking water. During this time, we began vaccinating children to help them avoid the most deadly diseases of childhood such as smallpox, and cleaning our teeth and bodies through the popularisation of soaps and toiletry products.