1822 - 1895
Born: 27 December 1822
Death: 28 September 1895
Birthplace: Dole, Jura, France
The next time you're enjoying a cold glass of milk with your
chocolate chip cookies, thank Louis Pasteur for making the milk
safe to drink.
While you're at it, you can also thank him that you don't have
smallpox, chickenpox, rabies, or diphtheria. Those diseases may
be rare now, but they were very much part of life in 18th and
19th Century Europe. That was before Pasteur made tremendous
discoveries in the fields of germ biology and immunology.
a French Chemist, is best known as the father of pasteurization.
That's the method of heating liquids until germs can no longer
live in them. Look on the label of your milk carton and chances
are it will say "pasteurized."
Born in 1822 in Dole, France, Pasteur was a talented young
artist. He could very well have succeeded in that field, but he
also showed an interest in chemistry.
While pasteurization bears his name, his most important
discovery could be that infections diseases are caused by germs.
Pasteur was able to control the spread of disease by limiting
the places where germs can live.
He also developed the theory that injecting a person with a
weakened form of a disease, such as smallpox, would make that
person immune from catching the disease.
"Vaccination" is the name of this technique that has been used
for decades to help control outbreaks of diseases such as
smallpox, chickenpox, cholera, diphtheria, anthrax and rabies.
In many ways, Pasteur was before his time. His recommendation
that hospitals boil their surgical tools went ignored until the
20th century. That's when surgeons recognized the need to
control germs in the operating room.
Pasteur studied at Besançon and Paris universities, and held
academic posts at Strasbourg, Lille, and Paris, where in 1867 he
became professor of chemistry at the Sorbonne.
Pasteur's discoveries were so groundbreaking that in 1888 an
international fund was created to fund the Louis Pasteur
Institute. Pasteur worked with the institute until his death. It
continues today as a center of microbiology and immunology.
The French chemist and biologist Louis Pasteur (1822-1895) is
famous for his germ theory and for the development of vaccines.
Louis Pasteur was born on Dec. 27, 1822, in the small town of
Dôle, the son of a tanner. He studied in the college of Arbois
and at Besançon, where he graduated in arts in 1840. As a
student preparing for the prestigious école Normale Supérieure
of Paris, he did not doubt his ability. When he gained
admittance by passing fourteenth on the list, he refused entry;
taking the examination again, he won third place and accepted.
For his doctorate his attention was directed to the then obscure
science of crystallography. This was to have a decisive
influence on his career.
Pasteur, under special dispensation from the minister of
education, received a leave of absence from his duties as
professor of physics at the lycée of Tournon to pursue research
on the optical properties of crystals of the salts of tartrates
and paratartrates, which had the capacity to rotate the plane of
polarized light. He prepared 19 different salts, examined these
under a microscope, and determined that they possessed
hemihedral facets. However, the crystal faces were oriented
differently; they were left-handed or right-handed, thus having
the asymmetrical relationship of mirror images. Furthermore,
each geometric variety of crystal rotated the light in
accordance with its structure, while equal mixtures of the
left-and right-handed crystals had no optical activity inasmuch
as the physical effects cancelled each other. Thus he
demonstrated the phenomenon of optical isomers.
Pasteur was elated; he repeated his experiment under the
exacting eyes of Jacques Biot, the French Academy's authority on
polarized light who had brought Eilhardt Mitscherlich's work to
Pasteur's attention. The confirmation was complete to the last
exacting detail, and Pasteur, then 26, became famous. The French
government made him a member of the Legion of Honour, and
Britain's Royal Society presented him with the Copley Medal.
In 1852 Pasteur accepted the chair of chemistry at the
University of Strasbourg. Here he found not only a wife but an
opportunity to pursue another dimension of crystallography. It
had long been known that moulds grew readily in solutions of
calcium paratartrate. It occurred to him to inquire whether
organisms would show a preference for one isomer or another. He
soon discovered that his microorganism could completely remove
only one of the crystal forms from the solution, the levorotary,
or left-handed, molecule.
Studies on Fermentation
In 1854, though only 31 years old, Pasteur became professor of
chemistry and dean of sciences at the new University of Lille.
The course of his activities is displayed in the publications
which he gave to the world in the next decades: Studies on Wine
(1866), Studies on Vinegar (1868), Studies on the Diseases of
Silkworms (1870), and Studies on Beer (1876).
Soon after his arrival at Lille, Pasteur was asked to devote
some time to the problems of the local industries. A producer of
vinegar from beet juice requested Pasteur's help in determining
why the product sometimes spoiled. Pasteur collected samples of
the fermenting juices and examined them microscopically. He
noticed that the juices contained yeast. He also noted that the
contaminant, amyl alcohol, was an optically active compound, and
hence to Pasteur evidence that it was produced by a living
organism ("living contagion").
Pasteur was quick to generalize his findings and thus to advance
a biological interpretation of the processes of fermentation. In
a series of dramatic but exquisitely planned experiments, he
demonstrated that physical screening or thermal methods
destroyed all microorganisms and that when no contamination by
living contagion took place, the processes of fermentation or
putrefaction did not take place either. "Pasteurization" was
thus a technique which could not only preserve wine, beer, and
milk but could also prevent or drastically reduce infection in
the surgeon's operating room.
Another by-product of Pasteur's work on fermentation was his
elucidation of the fact that certain families of microbes
require oxygen whereas others do not. Yeast, he showed, was a
facultative anaerobe; when oxygen was not present, as in the
vats of beer or wine manufacturers, it would derive its energy
from the sugar, converting it to alcohol; under more favourable
conditions (for the yeast) where oxygen was available, alcohol
did not accumulate, and the process continued to the complete
conversion of sugar to carbon dioxide and water. This insight
divided the scientific community, and it was only in 1897, 2
years after the death of Pasteur, that the dispute was resolved,
when a cell-free extract of yeast proved capable of fermenting a
sugar solution. Thus it turned out that the living organism
synthesized an enzyme which carried out the conversion.
Silkworms and Microbial Disease Theory
In 1865 Pasteur was called upon to assist another ailing
industry of France - silk manufacture - which was being ruined
by an epidemic among silkworms. He took his microscope to the
south of France and in an improvised laboratory set to work.
Four months later he had isolated the pathogens causing the
disease, and after 3 years of intensive work he suggested the
methods of bringing it under control.
Pasteur's scientific triumphs coincided with personal and
national tragedy. In 1865 his father died; his two daughters
were lost to typhoid fever in 1866. Over-worked and
grief-stricken, Pasteur suffered a cerebral hemorrhage in 1868
which left part of his left arm and leg permanently paralyzed.
Nonetheless, he pressed on, hardly with interruptions, on his
study of silkworm diseases, already sensing that these
investigations were but his apprenticeship for the control of
the diseases of higher animals, including humans.
The Franco-Prussian War, with its trains of wounded, stimulated
Pasteur to press his microbial theory of disease and infection
on the military medical corps, winning grudging agreement to the
sterilization of instruments and the steaming of bandages. The
results were spectacular, and in 1873 Pasteur was made a member
of the French Academy of Medicine - a remarkable accomplishment
for a man without a formal medical degree.
Pasteur was now prepared to move from the most primitive
manifestations of life, crystals and the simpler forms of life
in the microbial world, to the diseases of the higher animals.
The opportunity arose through a particularly devastating
outbreak of anthrax, a killer plague of cattle and sheep in
1876/1877. The anthrax bacillus had already been identified by
Robert Koch, and Pasteur now set about proving that the agent of
disease was precisely the living organism and not a related
toxin. He diluted a solution originally containing a source of
infection of anthrax by a factor of 1 part in 100100. Even at
this enormous dilution, the residual fluid carried death, thus
proving that it was the constantly multiplying organism that was
the source of the disease.
In 1881 Pasteur had convincing evidence that gentle heating of
anthrax bacilli could so attenuate the virulence of the organism
that it could be used to inoculate animals and thus immunize
them. In a dramatic demonstration of this procedure, carried out
with the whole of France as witness, Pasteur inoculated one
group of sheep with the vaccine and left another untreated. Upon
injection of both groups with the bacillus, the untreated died;
the others lived, and thus a scourge that had crippling economic
effects was brought under control.
Pasteur's ultimate triumph came with the conquest of rabies, the
disease of animals, particularly dogs, which gives rise to the
dreaded hydrophobia of humans. The problem here was that the
causative agent was a virus, hence an entity not capable of
growth in the scientists' broth which nurtured bacteria. Pasteur
worked for 5 years in an effort to isolate and culture the
pathogen. Finally, in 1884, in collaboration with other
investigators, he perfected a method of cultivating the virus in
the tissues of rabbits. The virus could then be attenuated by
exposing the incubation material to sterile air over a drying
agent at room temperature. A vaccine could then be prepared for
injection. The success of this method was greeted with
jubilation all over the world. Animals could now be saved, but
the question arose as to the effect of the treatment on human
beings. In 1885 a 9-year-old boy, Joseph Meister, was brought to
Pasteur. He was suffering from 14 bites from a rabid dog. With
the agreement of the child's physician, Pasteur began his
treatment with the vaccine. The injections continued over a
12-day period, and the child recovered.
Honours from the World
In 1888 a grateful France founded the Pasteur Institute, which
was destined to become one of the most productive centers of
biological study in the world. In the closing paragraphs of his
inaugural oration, Pasteur said: "Two opposing laws seem to me
now to be in contest. The one, a law of blood and death opening
out each day new modes of destruction, forces nations always to
be ready for the battle. The other, a law of peace, work and
health, whose only aim is to deliver man from the calamities
which beset him. The one seeks violent conquests, the other, the
relief of mankind. The one places a single life above all
victories, the other sacrifices hundreds of thousands of lives
to the ambition of a single individual. The law of which we are
the instruments strives even through the carnage to cure the
wounds due to the law of war. Treatment by our antiseptic
methods may preserve the lives of thousands of soldiers. Which
of these two laws will prevail, God only knows. But of this we
may be sure, science, in obeying the law of humanity, will
always labor to enlarge the frontiers of life."
Pasteur's seventieth birthday was the occasion of a national
holiday. At the celebration held at the Sorbonne, Pasteur was
too weak to speak to the delegates who had gathered from all
over the world. His address, read by his son, concluded:
"Gentlemen, 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.… Have faith that in
the long run … the future will belong not to the conquerors but
to the saviors of mankind."
On Sept. 28, 1895, honored by the world but unspoiled and
overflowing with affection, Pasteur died near Saint-Cloud. His
last words were: "One must work; one must work. I have done what
I could." He was buried in a crypt in the Pasteur Institute.
There is a strange postscript to this story. In 1940 the
conquering Germans came again 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
Frenchman killed himself. His name was Joseph Meister, the boy
Pasteur had saved from hydrophobia so long ago.
Pasteur was a French scientist who was a pioneer in
Louis Pasteur was born in Dole, France, the son of a tanner.
In his early work as a chemist he resolved a problem concerning
the nature of tartaric acid. A solution of this compound derived
from one source rotated the plane of polarization of light
passing through it. The mystery was that tartaric acid derived
by synthesis had no such effect, even though its reactions were
identical and its composition was the same.
Pasteur noticed, upon examination of the tiny crystals of
tartaric acid, that the crystals came in two asymmetric forms
that were mirror images of one another. Tediously sorting the
crystals by hand gave two forms of tartaric acid: solutions of
one form rotated polarised light clockwise; the other form
rotated light anticlockwise; and an equal mix of the two had no
effect on polarized light. Pasteur correctly deduced that the
tartaric acid molecule was asymmetric and could exist in two
different forms that resemble one another as a left- and
right-hand glove resemble one another. As the first
demonstration of chiral molecules, it was quite an achievement,
but Pasteur then went on to his more famous work in the field of
He demonstrated that fermentation and the growth of
microorganisms in nutrient broths were not due to spontaneous
generation. He exposed freshly boiled broths to air in vessels
that contained a filter to prevent all particles from passing
through to the growth medium and even in vessels with no filter
at all, with air being admitted via a long tortuous tube that
would not allow dust particles to pass. Nothing grew in the
broths; therefore, the living organisms that grew in such broths
came from outside, as spores on dust, rather than being
spontaneously generated within the broth.
With this established, he invented the process of
pasteurization, in which liquids such as milk were heated to
kill all bacteria and molds already present within them.
His later work on diseases included work on chicken cholera.
During this work, a culture of the responsible bacteria had
spoiled and failed to induce the disease in some chickens he was
infecting with the disease. Upon reusing these healthy chickens,
Pasteur discovered that he could not infect them, even with
fresh bacteria: the weakened bacteria had caused the chickens to
become immune to the disease, although they had not actually
caused the disease.
The notion of a weak form of a disease causing immunity to the
virulent version was not new: this had been known for a long
time for smallpox. Inoculation with smallpox was known to result
in far less scarring and greatly reduced mortality than with the
naturally acquired disease. Edward Jenner had also discovered
vaccination, using cowpox to give cross-immunity to smallpox,
and by Pasteur's time this had generally replaced the use of
actual smallpox material in inoculation. The difference with
chicken cholera was that the weakened form of the disease
organism had been generated artificially, and so a naturally
weak form of the disease organism did not need to be found.
This discovery revolutionised work in infectious diseases, and
Pasteur gave these artificially weakened diseases the generic
name of vaccines, to honour Jenner's discovery. Pasteur produced
the first vaccine for rabies, which was first used on 9-year old
Joseph Meister after he was badly mauled by a rabid dog in July
1886. This was done at some personal risk for Pasteur, since he
was not a licensed doctor and could have faced prosecution for
treating the boy. Fortunately, the treatment proved to be a
spectacular success, with the boy avoiding the disease. So
Pasteur was hailed as a hero and the legal matter was not
pursued. The treatment's success laid the foundations for the
manufacture of many other vaccines. The first of the Pasteur
Institutes was also built on the basis of this achievement.
Pasteur died in 1895 from complications caused by a series of
strokes that had begun plaguing him as far back as 1868. He was
buried in the Cathedral of Notre Dame, but his remains were soon
placed in a crypt in the Institut Pasteur, Paris.
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This web page was last updated on:
21 December, 2008