Louis Pasteur (1822 - 1895)
Louis Pasteur was born on December 27, 1822 in Dole, in the region of Jura, France. His discovery that most infectious diseases are caused by germs, known as the "germ theory of disease," is one of the most important in medical history. His work became the foundation for the science of microbiology, and a cornerstone of modern medicine.
Pasteur's phenomenal contributions to microbiology and medicine can be summarized as follows: First, he championed changes in hospital practices to minimize the spread of disease by microbes. Second, he discovered that weakened forms of a microbe could be used as an immunization against more virulent forms of the microbe. Third, Pasteur found that rabies was transmitted by agents so small they could not be seen under a microscope, thus revealing the world of viruses. As a result he developed techniques to vaccinate dogs against rabies, and to treat humans bitten by rabid dogs. And fourth, Pasteur developed "pasteurization," a process by which harmful microbes in perishable food products are destroyed using heat, without destroying the food.
Pasteur was a thorough, highly intuitive researcher who always considered the wider ramifications to his work. While he revered science, Pasteur always believed that there were spiritual values that transcend it. Pasteur was also a capable public speaker, often defending his positions on various controversies with eloquence.