3.1.1
Germ Theory, Pasteur & Koch
Germ Theory and the Work of Pasteur
Germ Theory and the Work of Pasteur
Before Louis Pasteur’s work in 1861, there was a debate over how infections were spread. Before Pasteur, most scientists believed spontaneous generation and that diseases could be spread by miasma or contact.
Spontaneous generation
Spontaneous generation
- Surgeons thought that microbes were caused by disease in something called “spontaneous generation”.
- The microbes were a symptom and diseases developed randomly, creating bacteria.
Spreading disease
Spreading disease
- The two main groups were contagionists and anti-contagionists.
- Contagionists believed disease could spread through contact.
- Anti-contagionists believed disease spread through miasma.
Pasteur
Pasteur
- In 1857, Pasteur tried to explain why the sugar beet used to ferment alcohol soured. Pasteur thought that germs in the air were responsible.
- He found that sterilised water was still sterile if the flask was closed, but was not sterile if the flask was open. This suggested that there were germs in the air.
Germ Theory
Germ Theory
- In 1861, he published his Germ Theory – germs were causing infections.
- Microscopes (invented in the 17th century) eventually allowed Pasteur to see the micro-organisms that he described.
Opposition to Germ Theory
Opposition to Germ Theory
- Pasteur faced serious opposition for his theory.
- A famous doctor called Charlton Bastian supported the theory of spontaneous generation, which contradicted Pasteur’s Germ Theory.
- Pasteur’s research focussed on how liquids, such as milk went sour (pasteurisation). Many did not see the connection to humans.
- Doctors did not believe that small germs could cause such harm to humans.
The Work of Robert Koch – Microbe Hunting
The Work of Robert Koch – Microbe Hunting
Using Pasteur’s Germ Theory, a German doctor called Robert Koch explained that germs could cause human disease. He linked a disease to the microbe that caused it. This was the beginning of ‘bacteriology’.
Different germs
Different germs
- Koch showed that germs were not all the same.
- He identified the different microbes that caused anthrax in 1876, septicaemia in 1878, tuberculosis in 1882 and cholera in 1883 by injecting animals with diseases. He then dyed bacteria and viewed them using microscopes.
- Other scientists then discovered typhus in 1880, pneumonia in 1880, tetanus in 1884, diphtheria in 1884 and the plague in 1890.
Germ Theory in the UK
Germ Theory in the UK
- Koch and Pasteur’s studies were picked up by many scientists in Britain.
- John Tyndall gave lectures on Germ Theory to British doctors. He refuted (disagreed with) Bastian’s ideas of spontaneous generation.
- Dr William Roberts created a medical version of Germ Theory.
Koch's work in the UK
Koch's work in the UK
- William Cheyne translated Koch’s work and highlighted that not all microbes caused harmful disease.
- Koch and Pasteur inspired a generation of scientists who were called ‘microbe hunters’.
- These scientists became interested in diseases and how to prevent them.
Pasteur and Vaccination
Pasteur and Vaccination
Pasteur and Koch tried to apply Germ Theory to develop more advanced vaccinations.
Chance discovery
Chance discovery
- In 1879, Pasteur accidentally showed that vaccinations could prevent disease.
- After a researcher Charles Chamberland left out a cholera culture over the weekend, they discovered that weakened (attenuated) cholera germs could make a chicken immune from later stronger bouts of cholera.
Vaccines
Vaccines
- In 1881, Pasteur produced a weakened (attenuated) vaccine for anthrax in sheep.
- By 1884, Pasteur created a vaccine for rabies. A year later this was applied to human subjects.
- Pasteur’s contribution to vaccines is so significant because it allowed some of the world’s deadliest diseases to be eradicated.
Rivalry and war
Rivalry and war
- In 1871, the Franco-Prussian war (between France and Germany) ended. Some historians think national rivalry between Pasteur and Koch drove developments.
- Scientific advances were propelled forward by competition.
Diphtheria
Diphtheria
- There was internal rivalry to understand a germ called diphtheria.
- By 1890, Pierre Roux had shown that diphtheria produced a poison.
- Later in 1890, Emil Behring showed that if diphtheria was diluted it could produce an antitoxin.
1Medicine Stands Still
1.1Ancient Egyptian Approaches to Medicine
1.2Ancient Greek Medicine
1.3Medieval Medicine
1.4Religion & Medicine
1.5Public Health in the Middle Ages
2The Beginnings of Change
2.1The Impact of the Renaissance on Britain
2.2Treating Illnesses in the Renaissance
3A Revolution in Medicine
3.1The Development of Germ Theory & its Impact
3.2A Revolution in Surgery
4Modern Medicine
4.1Modern Treatment of Disease
4.2New Diseases & Treatments in the 20th Century
5Themes in Public Health
Jump to other topics
1Medicine Stands Still
1.1Ancient Egyptian Approaches to Medicine
1.2Ancient Greek Medicine
1.3Medieval Medicine
1.4Religion & Medicine
1.5Public Health in the Middle Ages
2The Beginnings of Change
2.1The Impact of the Renaissance on Britain
2.2Treating Illnesses in the Renaissance
3A Revolution in Medicine
3.1The Development of Germ Theory & its Impact
3.2A Revolution in Surgery
4Modern Medicine
4.1Modern Treatment of Disease
4.2New Diseases & Treatments in the 20th Century
5Themes in Public Health
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