Passmores History Department

Why was the discovery of Germ Theory by Louis Pasteur in 1861 such a significant event in the history of medicine?

Background

In 1861 the French chemist Louis Pasteur made what is possibly the most important discovery in the history of medicine. Whilst working for a brewer he discovered that the cause of decay in organic matter was the presence of germs that existed in the atmosphere and floated in the air. From this Pasteur and the German Robert Koch went on to show the link between germs and disease. They then went on to develop explanations for diseases such as Cholera and Syphilis that had plagued humanity since prehistoric times. 

During the period before Pasteur doctors were ill equipped to deal with disease

Before Pasteur’s discovery all explanations of disease and illness were based on common sense, religion or guesswork

With no knowledge of the existence and impact of germs, doctors before Louis Pasteur had been working in ignorance of the real causes of the illnesses they observed. From the Prehistoric explanations based on supernatural causes, to Egyptian theories based on the body’s ‘channels’ to the Greek and Roman ideas of four humours and a balanced body, explanations of illness were at best sensible ideas based on observation and a bit of guesswork to ‘fill in the gaps’. Even during the European renaissance of the 15^th to 17^th centuries, no real advances had been made in explaining the causes of disease. 

This had disastrous consequences in the nineteenth century

With the growth of industrial cities in the 19^th century, mankind was faced with public health problems on a scale never before experienced. Outbreaks of Cholera in Britain in 1831, 1848 and 1854 and 1866 killed tens of thousands of people, and there was no real understanding of the causes of the disease. Even though campaigners such as Edwin Chadwick and Dr John Snow were able to show the link between poverty, dirty drinking water and cholera outbreaks, they lacked the scientific proof to back up their theories. It was still possible for governments and others to argue against public health measures in the absence of conclusive scientific proof of the causes of the widespread ill health of the 19^th century. 

Once Pasteur had made his discovery medicine was changed forever.

Doctors were able to prove why disease occurred

After thousands of years of being unable to truly explain the cause of disease, doctors were soon able to use Pasteur’s findings to explain disease. Pasteur’s work was developed by both himself and others such as the German Robert Koch. Within 35 years scientists and doctors had discovered the germs that caused the diseases that had ravaged humankind since the Stone Age. Leprosy, Diphtheria, Cholera and the Bubonic Plague all had their germs discovered in this period. Once this had been done, doctors were able to work on creating vaccines to prevent people from contracting the disease.

The next stage was to develop cures based on Germ Theory

Following work by the German Paul Erlich and the Japanese Sahchiro Hata, the first ‘magic bullet’ that could kill disease causing bacteria inside of the body was developed for human use in 1911. This was followed by other magic bullets named Sulphonamides. In 1929 Dr Alexander Fleming discovered Penicillin whilst searching for a cure for the Staphylococci bacteria. Ernst Chain and Howard Florey then developed this in the Second World War. These discoveries allowed doctors to treat patients for illnesses that had been fatal for thousands of years. All of this work came from Pasteur’s Germ Theory discovery. 

Germ Theory led to improved public health in Europe

Once the link between germs and disease had been proven, it was impossible for governments to refuse to undertake simple public health measures. Robert Koch showed that the Cholera germ was carried in unclean water supplies, and was spread by sewage and rubbish that was not properly removed. Armed with this knowledge public health campaigners were able to force the British Government to pass the compulsory Public Health Act in 1871. This forced councils to provide clean drinking water supplies and to remove sewage and rubbish from streets. This and subsequent acts revolutionised the health of Britons living in cities. Without Pasteur’s Germ Theory, any arguments for such simple measures were weakened by lack of scientific proof. 

In short 

Pasteur’s discovery of Germ Theory was significant in medical history because: 

• All ideas on disease and illness before Germ Theory were not proven scientifically and were actually little more than common sense or guesswork

·   Religious explanations of disease still had a foothold in medicine

·  The public health crises of the 19^th century were partly caused by ignorance of the real causes of the epidemics that swept across Europe

·   With the discovery of Germ Theory in 1861 doctors were able to fully understand the real causes of disease in humans

·    Doctors such as Pasteur and Koch were able to find the germs for human diseases and then find vaccinations for these diseases

·    Magic bullets to cure diseases once they had infected the human body were developed in the 20^th century as a result of Pasteur’s discovery

·    Public Health measures were taken in Britain after 1871 partly as a result of the discovery of Germ Theory