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Transcript of louis pasteur
Louis PasteurBy
Dhairya Nagpal
"Imagination should give wings to our thoughts, but we always
need decisive experimental proof.”
These are the famous words of Louis Pasteur who was one of the greatest scientists of the nineteenth century.
Born in France in 1822, Louis Pasteur became a scientific giant, laying the foundation for
several branches of science.
Pasteur is known as the father of microbiology and immunology; surprisingly, however, he began his career by studying the shapes of
organic crystals.
Pasteur worked with tartaric acid and racemic acid whose crystals can be found in fermenting wine. Although these were two different acids,
the chemical composition of the two was identical, and Pasture was determined to find
out how this was possible.
Upon intense inspection beneath his microscope, Pasteur examined both acids and noticed that
although they were identical, their spatial arrangement was different. One was the mirror image of the other. It was this discovery that led
to the science of stereochemistry.
Pasteur’s next study allowed him to solve the puzzle of alcoholic fermentation.
He concluded and was able to prove that living cells, the yeast, were responsible for
forming alcohol from sugar, and that contaminating microorganisms turned the
fermentations sour.
Upon this breakthrough, Pasteur then set out to find some of the specific
microorganisms responsible for normal and abnormal fermentations in such things as wine, beer, and vinegar.
Pasteur demonstrated that if these substances were
heated to a moderately high temperature for a few
minutes, this would kill the living microorganisms and
thereby sterilize (pasteurize) the substances and prevent
them from spoiling.
Pasteur’s discoveries
were still not complete!!!
During Pasteur’s time, there was great controversy over the theory of “spontaneous
generation”. Many people believed that things such as beetles, eels, maggots and microbes
arise spontaneously from decomposing matter.
Pasteur conducted a series of clever experiments that destroyed every
argument supporting "spontaneous generation". It was through these
experiments that Pasteur proved that all life comes from preexisting life.
Spontaneous Generation
The previous achievements of Louis Pasteur were immense, however,
they do not compare to the greatest achievements of Pasteur's career which was the development of the
germ theory of disease and the use of vaccines to prevent these
diseases.
While working on the study of fermentation, Pasteur noticed that the
contamination of such things as wine and beer was due to airborne yeast. Pasteur
thought that maybe this is how certain microorganisms (diseases) could be
spread.
Pasteur observed several hospitals and noticed that infection was spread by
physicians and hospital attendants from sick to healthy patients.
Germ Theory of Disease
Because of this observation and
remarkable finding, the germ theory of disease
came about. Now sanitation, hygiene, and
cleanliness are much more important in our society!
Germ Theory of Disease
ANTHRAX
Pasteur had a particular interest in the disease anthrax. Anthrax is an infectious disease that
affects cattle, sheep, and other livestock that can be transmitted to man.
During this time, anthrax was
responsible for killing large populations of
sheep in France, and this was detrimental
to the economy.
Pasteur supposed that if it were possible to give an animal a mild attack, this might be sufficient to
prevent the animal from getting the disease later on.
ANTHRAX
Pasteur’s hypothesis was correct. He eventually succeeded in producing a mild,
weakened, harmless culture of anthrax bacteria. He then took this culture and
vaccinated hundreds of livestock, and they were then immune to the disease.
Pasteur is predominantly well-known for his work with rabies also known as hydrophobia.
Rabies is a highly contagious, infectious disease that attacks the central nervous
system. This disease is commonly looked upon with horror.
RABIES
Many people have the misconception that those who have rabies act like a wild dog, barking and howling. Rabies enters the body through the bite
of an infected animal or infected saliva.
RABIES
On July 6 ,1885, Pasteur tested his new rabies vaccine
on man for the first time. Joseph Meister was a young man who had been bitten by a rabid dog. Urged to treat him with his new method, Pasteur gave Meister the
rabies vaccine and saved his life.
Rabies was the last achievement for the
astonishing scientist. Louis Pasteur could
be deemed one of the greatest benefactors
of humanity due to his numerous
contributions.
Pasteur was responsible for some of the most important theoretical
concepts and practical applications of modern science that we see and
still use today.
Acknowledgements
• All clipart in this show is compliments of Microsoft.
• The movie and sound clip were compliments of altavista.
• Information from www.louisville.edu/library/ekstrom/spe
cial/pasteur/cohn.html
Presented by:
DHAIRYA
Presented to:
SCIENCE CLUB MEMBERS AND
RESPECTED TEACHERS
DHAIRYA NAGPAL