Pasteur, Louis (1822–95)

Louis pasteur was a polymath French scientist who made many important contributions to modern medicine, including the use of vaccines for anthrax and rabies. He also contributed to the area of stereochemistry, and the term pasteurization carries his name. Pasteur was born the son of a once indentured tanner and showed early promise as a boy, but primarily in art. He took a second degree in science and then a doctorate, with early work involving crystallography. This work resulted in his discoveries concerning asymmetry within biological molecules and the understanding that the structure of the molecules, as well as their composition, help to determine their properties. This was achieved through dividing crystals into their right- and lefthanded states, which were mirror images of each other. Pasteur moved from one topic to the next, steadily progressing through careful science and logical deduction in new but related fields of study.

Pasteur continued his work on molecular asymmetry during his early academic career. When he was appointed dean of the faculty of science at the university in Lille, France, he became involved in the study of alcohol fermentation, since that was an important industry in his new home city. Pasteur's work with asymmetrical molecules had persuaded him that such asymmetry was congruent with the presence of life. Systematic examination of yeasts and other biological inputs helped him to identify the microorganisms that were responsible for impurities that had proven harmful to health and industry. He subsequently determined that heating beer and wine would kill those microorganisms and produce a pure flow of the outputs through the process of pasteurization. His methodical approach led to brilliant results and he was also asked to investigate the silk industry in France, which was close to collapse as a result of two diseases suffered by the silk worms. Pasteur investigated with his microscope and was able to identify the agents causing the diseases and suitable methods for combating them. By helping to create industrial guidelines and supervising the training of workers, Pasteur saved the European silk industry.

Pasteur's work with alcohol fermentation helped him definitively solve the so-called self-generation problem, which had perplexed scientists for thousands of years. This concerned the reason why biological matter should seem spontaneously to come into being, as for example the growth of molds or the eruption of maggots from a corpse. Pasteur identified the presence of microorganisms as instrumental in these events and proved this through systematic experimentation. Using a similar concept as other [Page 1345]scientists in the field, he came to the understanding that such microorganisms or germs were responsible for the spread of many diseases and infections. From this understanding and the application of empirical science, Pasteur was able to develop vaccines for anthrax and rabies, among other diseases, that have helped save millions of lives.