Glas flask used by Louis Pasteur, 1860s.
© Science Museum / Science & Society Picture Library
This flask was used by the French chemist, Louis Pasteur (1822-1895), in his experiments to show that germs are the cause of disease and decay. In order to prove that germs are present in air and will grow in a sterile nutrient medium, Pasteur boiled broth in glas flasks and sealed the ends to prevent air from entering. The broth stayed unspoilt until the flasks were opened, proving Pasteur's theories. This flask has remained sterile since the day that it was heated and sealed during the 1860s. Pasteur developed the pasteurisation proces which kills pathogens in milk, wine and foods, and produced vaccines against anthrax and rabies.