Louis Pasteur
By
Jamie Mignot
Friday, February 27, 2004
"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!!!
MULTIPLE CHOICE
What two types of acids did Pasteur
base his study of organic crystals?
1.
2.
3.
4.
5.
Steric and Hydrofluoric acids
Tartaric and Steric acids
Tartaric and Racemic acids
Racemic and Oleic acids
Steric and Racemic acids
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.
Spontaneous Generation
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.
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.
Germ Theory of Disease
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
Pasteur’s germ theory of disease
stated that most infectious diseases
are caused by micro-organisms.
It was time for Pasteur to apply his
research on the 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 carefully studied anthrax and noticed
that some cows developed the disease more
severely than others. So he decided to inject two
cows with a strong dose of the anthrax bacteria,
fully expecting them to die. Did they die?
To Pasteur's amazement neither of the
cows developed the disease. Later, he
found that both animals had already
suffered from anthrax.
Pasteur asked himself some
questions. Could they be immune
to it? Could they be protected in
some other way? What do YOU
think?
ANTHRAX
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.
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.
Click on the speaker to hear a sound clip about
Pasteur’s discovery!
RABIES
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. When you hear of the
disease rabies, what do you think of?
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
Pasteur experimented with the infected
saliva of rabid dogs and came to the
conclusion that it did indeed affect the
central nervous system. By studying the
tissue of infected animals, Pasteur was
able to produce diluted form of the virus.
Would this vaccine work?
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.
Click here to see a short movie clip on how
the flu vaccine is created
True or False
Louis Pasteur developed
several vaccines for many
infectious diseases.
True
False
Pasteur was responsible
for some of the most
important theoretical
concepts and practical
applications of modern
science that we see and
still use today.
Scavenger Hunt
• Click here to check out my
web scavenger hunt!
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/spec
ial/pasteur/cohn.html