Pasteur, Koch and the race for vaccines, 1861 to 1890

Germ theory turned into a race between French and German scientists to identify microbes and stop them. Their rivalry produced new vaccines and new methods that changed medicine.

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Pasteur proves germ theory

In 1861 Louis Pasteur published his germ theory: microbes in the air cause decay.
With swan-necked flasks, he showed that a sterile liquid stayed fresh when microbes could not reach it, disproving spontaneous generation.
He worked out how to weaken microbes to make vaccines. In 1879 an old culture of chicken cholera failed to kill chickens and then protected them.
In 1881 he publicly vaccinated sheep against anthrax at Pouilly-le-Fort: vaccinated sheep survived, the others died.
In 1885 he used a rabies vaccine on a boy, Joseph Meister, who survived.

Koch identifies the culprits

Robert Koch in Germany proved in 1876 that a particular bacterium causes anthrax.
He developed methods to stain bacteria with dyes, photograph them, and grow them on solid jelly so they could be studied one type at a time.
He identified the bacterium that causes tuberculosis (1882) and cholera (1883).
The rivalry between the two teams was sharpened by the Franco-Prussian War (1870 to 1871), and governments funded them as a matter of national pride.

Building on Koch

Koch's methods let his students find more microbes. Emil von Behring developed an antitoxin for diphtheria in 1890; in 1901 he received the first Nobel Prize in medicine.
The search for chemicals that killed microbes led Paul Ehrlich to Salvarsan 606 (1909), the first 'magic bullet'.
Together these discoveries moved medicine from guessing about causes to identifying specific microbes and attacking them.
Worked example

Explain why the work of Pasteur and Koch progressed so quickly.

  1. Rivalry: the Franco-Prussian War made each nation want its scientists to win.
  2. Government funding paid for laboratories and teams of assistants.
  3. Technology: better microscopes, dyes and photography let them see and record microbes.

Answer: National rivalry brought government money and teams, and new technology let them identify and record microbes.

Key idea

Pasteur: germ theory (1861), swan-necked flasks, chicken cholera (1879), anthrax vaccine at Pouilly-le-Fort (1881), rabies vaccine for Joseph Meister (1885). Koch: anthrax bacterium (1876), staining and growing bacteria, TB (1882), cholera (1883). Rivalry after the Franco-Prussian War and government funding sped progress. Behring's diphtheria antitoxin (1890); Ehrlich's Salvarsan 606 (1909).

Key words
Germ theory
Pasteur's theory (1861) that microbes cause decay and disease.
Magic bullet
A chemical that kills a particular germ without harming the body, such as Salvarsan 606, found by Ehrlich's team in 1909 to treat syphilis.

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  1. What theory did Pasteur's swan-necked flask disprove?

    1. Spontaneous generation
    2. Germ theory
    3. The four humours
    4. Miasma alone
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    Answer: Spontaneous generation

    Microbes came from the air.

  2. How did Pasteur's assistant help the chicken cholera discovery?

    1. He injected himself
    2. He bred new chickens
    3. He left a culture over the summer, which weakened it
    4. He used X-rays
    Show the answer

    Answer: He left a culture over the summer, which weakened it

    Weakened germs protected the chickens.

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Checked by the GCSE-ready editorial team, 17 October 2026. Last updated 2 October 2026. Spotted a mistake? Tell us and we will fix it.

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