ALPHABETICAL BRAIN™ VOCABULARY #5 of 100 MOST INFLUENTIAL SCIENTISTS #5 LOUIS PASTEUR Life Dates: 1822-1895 GERM THEORY OF DISEASE AND INVENTOR OF PASTEURIZATION Louis Pasteur was a French chemist and microbiologist renowned for his discoveries of the principles of vaccination, microbial fermentation and pasteurization. He is remembered for his remarkable breakthroughs in the causes and preventions of diseases. His discoveries have saved countless lives ever since. He reduced mortality from puerperal fever, and created the first vaccines for rabies and anthrax. His medical discoveries provided direct support for the Germ Theory of Disease and its application in clinical medicine. While Pasteur was not the first to propose the germ theory (Girolamo Fracastoro, Agostino Bassi and others had suggested it earlier, with the significant experimental demonstration by Francesco Redi in the 17th century), he developed it and conducted experiments that clearly indicated its correctness and managed to convince most of Europe that it was true. Today, he is often regarded as one of the Fathers of Germ Theory. However, Pasteur is best known to the general public for his invention of the technique of treating milk and wine to stop bacterial contamination, a process now called pasteurization. And he is now regarded as one of the three main founders of bacteriology, along with Ferdinand Cohn and Robert Koch, and is popularly known as the Father of Microbiology. Pasteur was responsible for defeating the Doctrine of Spontaneous Generation. He performed experiments that showed that without contamination, microorganisms could not develop. Under the auspices of the French Academy of Sciences, he demonstrated that in sterilized and sealed flasks nothing ever developed, and in sterilized but open flasks microorganisms could grow. This experiment won him the Alhumbert Prize of the Academy. Pasteur also made significant discoveries in chemistry, most notably on the molecular basis for the asymmetry of certain crystals and racemization. Early in his career, his investigation of Tartaric acid resulted in the first resolution of what we now call optical isomers. Pasteur's work led the way to our current understanding of the fundamental principal of optical isomers in the structure of organic compounds. SOURCES = The Scientific 100 by John Simmons (pages 27-32); Britannica Encyclopedia; and Wikipedia. instantly go to: NUMERICAL LIST OF 100 MOST INFLUENTIAL SCIENTISTS IN HISTORY or return to: ALPHABETICAL BRAIN™ VOCABULARY INDEX