Louis Pasteur

Louis Pasteur lived long ago. But the things he did help keep you healthy today. He was not a medical doctor. Yet he found new ways to help keep people from getting ill. Pasteur studied germs. He figured out that germs could live almost anywhere. He believed that these germs caused sickness.

Pasteur proved that sicknesses happen when germs get inside a body and multiply. He also found that if a few weak germs were put into an animal, the animal’s body would develop its own defense against the germ. He proved this by giving sheep and chickens shots of weak germs. And it worked! Those animals no longer caught the bad sicknesses. In 1881 he started work on a shot to stop rabies. Four years later, a rabid dog bit a boy.

The parents asked Pasteur to save their son. Pasteur did not want to use his shot on a person. He was not sure what would happen. But he knew that the boy was sure to die without it. The shot was his only chance. So Pasteur gave him the first human vaccine. The little boy lived.

Pasteur wanted to come up with a way to keep germs from getting into people’s bodies. He found a way to make milk free of germs. He learned that germs could not stand heat. When he heated milk to 140°F and then quickly cooled it and sealed it in clean jars, the germs died. His method is called pasteurization. It has been used on milk ever since. Today it is used to prevent germ growth in other products, too.