Louis Pasteur’s works created new milestones in medical history.
Amongst them, his two major works, the Germ Theory of Disease and
Pasteurization, are the cornerstones of modern medicine and the science of
Microbiology. He worked throughout his life in solving practical problems of the industry,
agriculture and medicine. The entire world benefited from his discoveries and new
techniques that saved countless lives. He paved the ways for prevention of Silkworm
diseases, Anthrax, Chicken Cholera and Rabies.
He proved that
microorganisms cause fermentation and disease. The credit for saving the beer, wine, and
silk industries among others, of France as well as of the world, goes to him. What marks
out Pasteur as a scientist is not his path-breaking achievement in science, but his
concern for humanity at large. The network of Pasteur’s discoveries has been knitted
in an organized manner, which begins with Molecular Asymmetry and ends with his Rabies
Prophylaxis.
CRYSTALLOGRAPHY :
FOUNDATION OF STEREOCHEMISTRY
The father of Microbiology
and Immunology, Louis Pasteur launched his scientific career by studying the shapes of
organic crystals. At the age of 26, in 1847, he was working for his doctorate in Chemistry
at the laboratory of Antoine Ballard. In those days, Crystallography was not so developed
a branch of chemistry.
While working with tartaric
acid crystals, which were suppose to refract light in one direction only, Louis found that
there were two kinds of such crystals having a property known as polarization. One type of
crystal polarized the light to the right, the other to the left. They were exact replica
of each other. By merging the two types, Louis was able to produce an optically natural
crystal. Thus, he proved that the crystals have two kinds of structures and named them
isomers. His first work on molecular asymmetry formulated a fundamental law: Asymmetry
differentiates the organic world from the mineral world. This discovery led to the
creation of a new science - Stereochemistry.
FERMENTATION :
FOUNDATION OF MICROBIOLOGY
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The discovery of molecular asymmetry enriched Pasteur with the "inescapable forward moving logic." This logic led him towards studies of alcoholic fermentation. While serving as Dean at the Faculty of Sciences in Lille, Pasteur moved from Chemistry to Biology. At that time, Lille was the center of the sugar beet area in France. A leading industrialist called Monsieur Bigo, who complained that the alcohol was often contaminated in fermentation process, approached Pasteur. He visited Bigo’ factory, and took several samples of both, the healthy mash and the sick mash. He examined them under the microscope. There were little globules of yeast. He also found several smaller structures. He named them ferments, which are known as microbes today. He explained that by eliminating these microbes in the fermenting fluid, pure alcohol could be produced. Soon after, he did further experiments on fermentation. |
He reached the conclusion
that each type of fermentation is linked to the existence of a specific ferment
[micro-organism], which is a living being that can be studied by cultivation in an
appropriate sterile medium. In 1857, he published a paper on fermentation, which was the
basis of a new scientific branch, Microbiology. Pasteur’s success led to the solution
of a problem faced by the French wine industry.
PASTEURIZATION
It was Emperor
Napoleon-III, who asked Pasteur to find out the causes afflicting wine industry, which
resulted in considerable economic losses to the wine industry of France. Pasteur moved to
a vineyard in Arbois in 1864 and began to study the problem. He showed that fermentation
involved microorganisms. He recommended the correct type, rather than that for lactic acid
producing yeast, meant to be used in the winery for producing alcohol.
He recommended that, to
prevent spoilage of the wine during fermentation, it should be heated up to 55º C. He
applied this process of gentle heating to many foods like beer and milk that went sour
rapidly. It was a technique of killing the unwanted bacteria and then ensuring the
container airtight. This heating process is today known as Pasteurization. Following this
discovery, Louis Pasteur became one of the most acclaimed scientists not only of France,
but of the entire world. Modern Pasteurization standards for milk require heating it at
about 63º C temperature for 30 minutes.
SILKWORMS
The year 1865 was
disastrous in terms of economic loss for France. The southern area of France was the heart
of the silk industry, which contributed to a great extent, to the economic mite of the
nation. When this important industry was threatened by a disease that was killing the
silkworms, one of Pasteur’s old professors of chemistry, Professor Dumas asked
Pasteur to rescue the industry from its imminent doom. The Ministry of Agriculture
commissioned Pasteur to sort out the problem. Pasteur was a bit confused. He told
Professor Dumas, "I know nothing about the subject." The Professor answered,
"All the better! You will only have the ideas that come from your own observations
!" Dumas’ words inspired Pasteur to take up the challenge. He moved to the
affected area, the center of silkworm breeding. After three years’ hard work, he
succeeded in isolating the bacilli of two distinct diseases – Pebrine and Flacherie.
He worked out techniques for improving hygiene in the silkworm nurseries. He instructed
the farmers to destroy all leaves, upon which the silkworms had fed. The silk industry was
saved from catastrophe. This experimental success proved him to be a true patriot apart
from a great scientist. |
