Louis Pasteur was born on December 27, 1822, in Dôle, a small town in France. He grew in a humble family and his father was a tanner. He graduated in 1840 from the College of Arts at Besancon and entered the prestigious Ecole Namale Supervieure, Paris, to work for his doctorate degree. He chose for his studies the then obscure science of crystallography, which was to have a great influence on his career. Pasteur entered the scientific world as a professor of physics at the Lycee of Tournon and started his research on the optical properties of crystals of tartaric acid salts. He found the two forms of this acid which could rotate the plane of polarization of light, one to the right and the other to the left. This was his first important discovery in crystallography, the phenomenon of optical isomers. Paradoxically it incited him to abandon the field. But it won the acclaim of the French Academy and Britain’s Royal Society. Thus Pasteur became famous at the age of 26.
Pasteur soon began researching the complexities of bacteriology. The prevalent theory of life at the time was spontaneous generation which states that certain forms of life such as flies, worms, and mice can develop from non-living matter such as mud and decaying fish. Pasteur disproved this theory with a simple experiment. He showed that microorganisms would grow in sterilized broth only if the broth was first exposed to air containing spores, or reproductive cells. His findings led to the development of the cell theory of the origin of living matter which states that all life originates from preexisting living material. In 1849, Pasteur became professor of chemistry at the University of Strasbourg, where he began studying fermentation, a type of chemical breakdown of substances by microbes. He served the rest of his career as Dean of Sciences at the University of Lille. Soon after his arrival at Lille, Pasteur was asked to solve the problems of the local industries, vinegar and silk manufacture. A producer of vinegar from beet juice wanted to know why the product was sometimes spoilt. On examining the juice microscopically, Pasteur observed that the contaminant, amyl alcohol, was optically active. This gave clear evidence that it was produced by a living organism. Pasteur then proposed a biological interpretation of the process of fermentation. He demonstrated that when no contamination by living contagion took place, the process of fermentation or putrefaction did not take place. Thus the celebrated techniques of Pasteurization, came into being, it could not only preserve wine and milk but drastically cut inflation in the surgeon’s operating table. Today pasteurization follows closely the early techniques of Louis Pasteur. In the case of milk pasteurization, the milk is heated to 161°F for 15 seconds followed by a rapid cooling to 50°F or lower. This process removes any unwanted bacteria, but also kills any beneficial bac! teria and reduces some of the nutritive property of milk. The Franco-Prussian War opened an avenue to press his microbial theory of infection, he got the grudging agreement of the military medical corps to sterilize instruments and steam bandages. As a result, thousands of lives were saved. In 1873, Pasteur was elected to the French Academy of Medicine, a spectacular achievement for a person without a medical degree. Pasteur was now ready to move from the simpler forms of life in the microbial world to the diseases of the higher animals. The opportunity came through a devastating outbreak of anthrax, a killer plague of sheep in 1876. Pasteur tried to produce pure cultures, his objective was to fight the disease and not just to describe it. Pasteur had accidentally forgotten in a corner of the laboratory a culture of fowl cholera and noticed that it had lost some of its virulence. Then he vaccinated some chicken which resisted the disease. The same technique, after improvement, was applied against bacillus anthracis: sheep inoculated with the vaccine survived and the non-vaccinated ones died. A scourge that had crippling economic effects was brought under control. Simultaneously, the principle of immunization or the protection of the body through vaccines was discovered. In 1865, the silk industry of France faced an economic ruin by an epidemic among silkworms. He proceeded to the south of France and set up an improvised laboratory. He isolated the pathogens causing the disease and after three years of intensive work, he suggested suitable remedies. This achievement coincided with personal tragedy in his life: his two daughters died of typhoid fever in 1866. In 1868, he suffered a set back in health, his left arm and leg being permanently paralyzed. Nonetheless, he continued with grim determination, his study of silkworm diseases, which he perceived, will help control diseases of higher animals, including man. Pasteur then started work on rabies, the disease of animals, particularly dogs. The causative agent was a virus, an entity not capable of growth in scientists’ broth, which nurtured bacteria. Pasteur worked for five years to isolate and culture the pathogen. Finally he prepared a vaccine for injection. Animals could now be saved but the effect of trying out on humans had to wait. On July 6, 1885, Joseph Meister with 18 bites from a rabid dog, was brought to Pasteur. He treated him over a 12-day period with the vaccine and the boy was saved. Pasteur is remembered for his innovative work as a teacher. He introduced changes every year in the material he taught in his class, as his main concern was to present an image of science open to debate and discussion rather than based on fixed notions. All along his career, Pasteur maintained a meticulous record of his laboratory work, in which he noted every day all his observations: description of experiments, new projects, notes on techniques of brewers, wine growers, sericulturists, drafts of letters, papers to scientific societies. Due to the extreme rigor and care with which Pasteur used to write his notes, they became an essential work tool. Pasteur’s seventieth birthday in 1892 was celebrated in a unique way, by being observed as a national holiday in France. His address on this occasion carried a thoughtful message: “You bring me the greatest happiness that can be experienced by a man whose invincible belief is that science and peace will triumph over ignorance and war…. In the long run the future will belong not to the conquerors but to the saviors of mankind”. Pasteur, honored by the world but unaffected, died on September 28, 1895, he was buried in a crypt in the Pasteur Institute. In 1940, the conquering Germans came to Paris. A German officer demanded to see the tomb of Pasteur, but the old French guard refused to open the gate. When the German insisted, the guard killed himself. The latter was Joseph Meister, whom Pasteur had saved from hydrophobia.
Louis Pasteur made many valuable contributions to the fields of chemistry, medicine, and industry with findings and research still applicable today. In making discoveries concerning the spreading of diseases he was able to prevent the loss of many lives. Pasteur was a remarkable scientist who put his basic discoveries to use in everyday problems in health and industry.