Transcript Louis Pasteur - Famous Scientists

27th December 1822 – 28th September 1895
Contents
Louis Pasteur was a French scientist and microbiologist, who is best known for
his remarkable discoveries in the causes and prevention of diseases.
Click on the topics below to find out more.
• A short biography
• Pasteur and pasteurisation
• Pasteur and infection
• Pasteur’s Theory of Germs
• Pasteur’s other achievements
A short biography of Louis Pasteur
Louis Jean Pasteur was born on 27th December 1822 in France and grew up in the town
of Arbois. His father, Jean Pasteur, was not very well educated, but Louis attended
school and it was there that his headmaster noticed how intelligent he was and
suggested that he applied to go to a special college to continue his studies.
As an adult, Pasteur worked as a professor of science in a number of universities.
During this time he met Mary Laurent, who would later become his wife.
Mary and Louis Pasteur married on 29th May 1849 and
together they had five children, although only two survived
into adulthood. Three of his children died of Typhoid fever,
which some people believe may have been what inspired
Pasteur to dedicate his life to getting rid of diseases.
Pasteur died in 1895 near Paris. He had been ill for some
time after suffering a number of strokes. He died listening
to stories about one of his heroes, St Vincent de Paul.
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Pasteur and Pasteurisation
Pasteur was asked to find out why beer and wine go sour, as this caused the
makers to lose a lot of money. After a number of experiments, he discovered
that the sour taste was caused by bacteria (a type of micro-organism).
Later in his life, he realised that it was also bacteria that made milk turn sour.
Pasteur determined to find a way to prevent this from occurring. Eventually
he found that the bacteria could be removed from the liquid by first boiling it
(which kills the bacteria) and then cooling it again.
This method was named after Louis Pasteur and is known as pasteurisation.
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Pasteur and his Theory of Germs
In those days, many scientists believed that microorganisms could simply
appear from nowhere, but Pasteur proved this to be wrong. This is how he
convinced most of Europe that microbes were present in the air all around us
and could not simply appear
1. He filled containers with broth (the special liquid that scientists used to
feed microorganisms), but boiled it to make sure that there were no live
microbes in it.
2. He then used air filters, so that no microbes from the air could get in and
grow in the broth. This meant that if any microbes DID grow in the broth,
then they had simply appeared by themselves.
3. Pasteur discovered that no microbes grew in the broth, so he concluded
that they must usually get into the broth from the air all around.
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Pasteur and Infection
Pasteur spent a lot of time visiting hospitals and became convinced that the same
type of microbe that turned drinks sour (bacteria) could also make humans and
animals ill.
Pasteur knew that diseases could pass from one person to another, but soon
realised that sometimes it was the doctors and other hospital staff who were
spreading the diseases from patient to patient. He encouraged the doctors to make
sure that their hands, as well as bandages and other medical equipment were
extremely clean before they were used so that they were not covered with microbes
that would spread disease.
Pasteur recommended that medical equipment was sterilised (made disease-free)
by heating it to a very high temperature, which he knew would kill bacteria.
This work of Pasteur would later inspire another famous scientist, Joseph Lister.
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Pasteur’s other Achievements
Louis Pasteur’s understanding of microbes and disease meant that he was able to
help many millions of people. Here are just a few of his other discoveries
• He became the hero of the textile (fabric making) industry by realising that a
parasite was killing the silk worms. He suggested that they got rid of this parasite
in the places where the silk worms were kept, and this resulted in the disease being
eliminated.
• Many people were very frightened of a disease called rabies, which was spread by
animal bites and could make the patient very ill. Pasteur found a small amount of
the microbe that caused rabies and made it weaker so that it couldn’t cause the
disease. Then he injected the microbe into a dog. The dog’s body became used to
the microbe and learnt to fight it off. After some time, the dog was injected with
some microbes (not a weakened version this time) and it did not become ill.
Pasteur had created a vaccine that prevented an animal from getting rabies!
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