Pasteur, Louis

Pasteur, Louis (1822-95), French scientist.

Louis Pasteur started his career as a physics master in a high school, but by the age of twenty-six, was a professor at Strasbourg University.

Later he moved to Lille University and there, in 1856, he made a discovery of enormous importance to doctors.

He was studying the way that grape juice was made into wine in a factory in Lille. It underwent a change called fermenting. Previously scientists had believed that this was simply a chemical change. But Pasteur found out that it was caused by tiny living organisms which are found in the air and elsewhere. They are called bacteria or germs.

Pasteur made many more discoveries about germs. He found out for example that they were killed by heating. Germs multiply rapidly in milk and this used to cause diseases, notably tuberculosis. Pasteur's discovery was applied to milk, and today most of the milk we drink is said to be pasteurised. This is when it is heated to 71°C for 15 seconds to kill the germs.

Pasteur also showed that people and animals could be inoculated against diseases. Robert Koch discovered the germ causing anthrax and Pasteur produced an inoculation against it.

He also produced an inoculation against rabies in dogs. In his day, people were often bitten by mad or rabid dogs and suffered a disease called hydrophobia. Pasteur's rabies inoculation cured this, too.

In 1865, the silk industry in France was being ruined by disease attacking the silk-worms. Pasteur worked on this problem for six years. He finally found the causes of the disease and a means of controlling it.

On Pasteur's seventieth birthday, doctors and scientists from all over the world met in Paris in his honor.

The kind of work Pasteur did has been continued since 1888 at the Pasteur Institute in Paris, Institut Pasteur, and today it has branches in many countries. Pasteur is buried under the Institute in a tomb of marble and granite.

See Patrice Debré Louis Pasteur