Called "a living symbol, embodying both science and France," by biographer Patrice Debre, scientist Louis Pasteur (1822-1895) laid the foundation for microbiology and modern medicine.

"Let me tell you the secret that has led me to my goal," he once said. "My strength lies solely in my tenacity."

The great scientist was born on this day in Dôle, Jura, in the eastern part of France. He trained in physics and chemistry.

"Do not put forward anything that you cannot prove by experimentation," advised Pasteur, who postulated the germ theory of disease.

Pasteur was a catalyst for revolutionary ideas in science. An advocate for sterilization of medical instruments, he made sure that health professionals washed their hands and disinfected gauze and bandages to prevent the spread of deadly diseases.

"The greatest disorder of the mind is to let will direct it," he said.

He developed pioneer vaccines against anthrax, cholera, and rabies and introduced a technique of heat treatment to preserve food now known as pasteurization.

"In the fields of observation," he advised, "chance favors only the prepared mind."

Celebrate the god within.