Louis Pasteur was a French scientist who made breakthroughs throughout the 19th century. He was born into a poor family that produced leather. He later managed to enroll into a very upscale college, and then began his work as a chemist.
He proved that micro-organisms were the main cause of most diseases, a belief commonly rejected in Europe before his time. He also proved that micro-organisms also were the reason of why many beverages spoil. He invented a process of heating up the liquids and then cooling them which is called pasteurization in his honor. Many drinks are still pasteurized today including milk and orange juice.
His work led to the many vaccines being created that led to lengthening the lifespan of the common man from every nation in the world. Pasteur himself created the first rabies vaccination. He died in 1895 at the age of 72 from a series of strokes leaving a better world and a mighty legacy behind him.