27th December 1822 – 28th September 1895 Louis Pasteur 27th December 1822 – 28th September 1895

Click on the topics below to find out more. 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. Back to Contents

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. Back to Contents

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 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. 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. 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. Back to Contents

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. Back to Contents

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! Back to Contents