Louis Pasteur

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• Born: 27 December 1822
• Birthplace: Dole, Jura, France
• Died: 28 September 1895 (complications from a series of strokes)
• Best Known As: Renowned inventor of pasteurization

Louis Pasteur is the 19th-century biologist and chemist whose work with germs and micro-organisms opened up new fields of scientific inquiry, aided industries (ranging from wine to silk), and made him one of the world's most celebrated scientists. Pasteur became a professor of chemistry at the University of Lille in 1854, and soon began studying fermentation in wine and beer. He became convinced "the germs of microscopic organisms abound in the surface of all objects, in the air and in water." He determined that such micro-organisms could be killed by heating liquid to 55 degrees Celsius (about 130 degrees Fahrenheit) or higher for short periods of time. This simple process became known as pasteurization, a process used today in milk and many other beverages. Pasteur then turned his attention to other aspects of microorganisms. He virtually created the science of immunology, showing that certain diseases (like rabies) could be prevented by vaccination (his term), that is, injecting animals with weakened forms of the disease. So great were Pasteur's successes that an international fund was raised to create the Louis Pasteur Institute in 1888. Pasteur worked with the institute until his death, and it continues today as a center of microbiology and immunology.

For more information on Louis Pasteur, visit Britannica.com.

Louis Pasteur

Library of Congress

[b. Dôle, France, December 27, 1822, d. near Sevres, France, September 28, 1895]

In the 1850s, Pasteur was asked to study why products of fermentation, such as wine and beer, sometimes sour during production. He soon demonstrated that a specific microscopic organism causes each kind of fermentation, and that when other microorganisms get into the liquid, they can cause souring. He also showed that "germs" cause milk to sour and cause infectious diseases. Pasteur found that he could kill many microorganisms in wine by heating and then rapidly cooling the wine--a process now called pasteurization. While developing methods for culturing microorganisms in special liquid broths, Pasteur discovered that some microorganisms require air--specifically, oxygen--while others are active only in the absence of oxygen. He called these, respectively, aerobic and anaerobic organisms. In 1877 Pasteur began to study anthrax, a disease mainly of cattle and sheep. He developed a vaccine using a weakened strain of the anthrax bacterium. In 1885 he developed the first vaccination against rabies in humans.

(1822-1895) French biologist; founder of microbiology, developed the process of pasteurization.

Louis Pasteur (1822–1895), a French chemist and bacteriologist, was a pioneer in the fields of bacteriology and preventive medicine. He had already established an international reputation as a chemist and won the Rumford Medal of the British Royal Society for his work on the structure of crystals when he made his first foray into bacteriology in 1854. Having recently been appointed a professor of chemistry in Lille, Pasteur was invited to solve a problem in the fermentation of beer that affected its taste and rendered it undrinkable. He showed that this was caused by bacteria that could be killed by heat. In this way he invented the process for heat treatment to kill harmful bacteria, first applied to the making of beer, then to milk. This process has been known ever since as pasteurization.

He next turned his attention to two diseases of silkworms, showing these to be due to microparasites and demonstrating how these diseases could be prevented. Soon after this he suffered a stroke from which he was not expected to recover. Defying this prognosis, he went on to study and solve other bacteriological problems in both industry and animal husbandry. He showed that chicken cholera could be prevented by inoculating chickens with an attenuated vaccine and in 1881 he demonstrated that a similar attenuated vaccine could be used to control anthrax, which was then a serious threat to livestock, and occasionally to humans.

In 1880, Pasteur had begun experiments on rabies, seeking a vaccine to control this disease, which without treatment has a 100 percent death rate. Following the success of the anthrax vaccine he believed that an attenuated rabies vaccine could be made. The only way to test this vaccine would be on a human who had been bitten by a rabid dog, and this he did in July 1885. His patient was a boy, Joseph Meister. The vaccine worked, Joseph Meister survived, and Pasteur became not just a national but an international celebrity.

Pasteur made many other important contributions to microbiology and continued to work until near his death, despite the gloomy prognosis he had been given after his stroke more than a quarter of a century earlier. Pasteur's antirabies regimen consisted of multiple injections of rabies vaccine into the skin of the abdomen. This sequence of multiple (and painful) injections was used for many years without modification to prevent the onset of rabies in anyone who had been bitten by a rabid animal. No one was brave enough to try an experiment to determine whether a less protracted and painful regimen would be as effective. Only in the 1980s did the development of genetically engineered vaccines lead to a simpler way to prevent rabies. Pasteur's name lives on in the microbiological research institute in Paris that bears his name, the Institut Pasteur, and its branches in former French colonies in Africa and Asia.

(SEE ALSO: Immunizations; Rabies)

Bibliography

Dubos, R. J. (1996). Louis Pasteur, Free Lance of Science. San Francisco: Da Capo Press.

— JOHN M. LAST

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.

Stereochemistry Investigations

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 canceled 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 Honor, 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 molds 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 favorable 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.

Honors 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.

Further Reading

The definitive biographies of Pasteur are René Dubos, Louis Pasteur, Free Lance of Science (1950), and Pierre Vallery-Radot, Louis Pasteur: A Great Life in Brief (trans. 1958). See also Jacques Nicolle, Louis Pasteur, a Master of Scientific Enquiry (1961). For the technical achievement in microbiology see Henry James Parish, A History of Immunization (1965).

Pasteur, Louis (1822-95). Founder of microbiology. After his training in chemistry and biology, Pasteur's early work on fermentation led him to discover the micro-organisms which cause it, and to propose methods of preservation, one of which was named pasteurization. He developed the theory of germs and the method of asepsis as well as vaccines for anthrax and rabies. His flair for striking demonstrations, sometimes exceeding his rigour, made him a household name, and he was elected to the Académie Française in 1881. He founded the Institut Pasteur in Paris, which has maintained France's reputation in microbiology, most recently distinguished by its work on AIDS.

[Michael Kelly]

Coupling true scientific genius with a talent for dramatic self-promotion, Louis Pasteur (1822–1895) rose from humble beginnings as the son of a tanner in a small French village to international fame before his death.

Pasteur was trained as a chemist, and his earliest work on the crystals of tartaric acid, a naturally occurring by-product of wine production, caught the attention of several established chemists, who promoted his career and helped him secure an appointment as professor of chemistry at the University of Strasbourg.

Arriving in Strasbourg in January of 1849, he met Marie Laurent, daughter of the university's rector. With characteristic decisiveness, Pasteur proposed marriage within a few weeks, and in May of that year he and Marie were married. He chose well: For the rest of his life, Marie Pasteur supported and assisted him in his work; often they spent their evenings together, with Pasteur dictating notes or letters to his wife.

The Pasteurs moved in 1854 to the university at Lille, a thriving industrial area of France. Pasteur encouraged the practical application of science to the industries around him. His efforts on behalf of a local manufacturer who made alcohol from sugar beets were his first serious study of fermentation.

Moving on to Paris, he assumed positions at his old college, the Ecole Normale Supérieure, and later at the Sorbonne as well. He was not provided with a research laboratory, so he set one up at his own expense in a cramped unused space. This included a compartment under the stairs so small that he had to crawl in on his hands and knees to check his cultures.

In 1863, Emperor Napoleon III asked Pasteur to assist France in combating various "diseases" of wine that often caused exported French wine to go bad before it reached its destination. Pasteur believed that the yeasts observed in wine were the cause of fermentation, a fact that was not understood by much of the scientific community. These living yeasts appeared so mysteriously that many chemists believed they were generated spontaneously. Pasteur devised ingenious experiments to demonstrate that the yeasts came from the atmosphere. His belief in germs as causative agents that could infect a new medium on contact was sustained in his later work with animal and human diseases.

Pasteur also observed that other microbes besides the wine yeasts were present whenever the wines soured. In fact, he and his assistants soon learned to predict the taste of a wine according to which microbes they spotted in it with their microscopes. Pasteur urged the winemakers to provide conditions conducive to the growth of wine yeast and not to that of other microbes. He suggested a prolonged gentle heating, which discouraged undesirable microbes without altering the taste of the wine. A jury of wine experts conducted a taste test at Pasteur's request to establish that the taste was unaffected by the heating. This technique, which is today regularly applied to all kinds of foodstuffs, especially milk, quickly came to be called "pasteurization." Pasteur took out a patent on this process, but he soon allowed it to pass into the public domain. Though less dramatic than his later work with diseases, pasteurization is perhaps Pasteur's greatest contribution to the safety of food throughout the world. Pasteur was not the first to preserve foods by heating and protecting them from contamination, but he extended the practice to a variety of foodstuffs and offered a theoretical basis for its success.

Pasteur also advised vinegar makers, as well as the French beer industry. He hoped to make French beer superior to German as a gesture of revenge for the Franco-Prussian War of 1870. He taught hygienic practices to France's silk industry and, less easily, to the medical profession. The germ theory was then successfully applied to the development of vaccines for anthrax and other animal diseases, and finally to prevent the development of the dread rabies in human beings.

Pasteur achieved all this by dint of persistent hard work. His was not a balanced life. His labors, his ambition, and his aggressiveness in promoting his theories and reputation may all have been culprits in his severe stroke at age forty-five, which paralyzed his left side and left him with a limp. However, he continued to work for another two decades before his increasingly frail health gradually slowed him down.

Despite stirring up a good deal of controversy, Pasteur was given many honors in his lifetime. He received scientific prizes and awards and was elected to the French Academy of Sciences, the Academy of Medicine, and finally the august Académie Française. In 1888, the private Pasteur Institute was established in Paris, funded by contributions large and small from all over the world. Pasteur's seventieth birthday was the occasion for a national jubilee, and at his death he was given a state funeral in Paris before his body was interred in a grand tomb at the Pasteur Institute.

Even before his death, Pasteur was regarded, especially in France, almost as a secular saint. His earliest biographies were hagiographic, in keeping with the preference of the late nineteenth and early twentieth centuries for heroes of mythic proportions. The current age, on the other hand, needs to debunk, demythologize, and deconstruct the legends of the past. Accordingly, a modern reassessment of Pasteur has been in progress since the late twentieth century, aided by material from Pasteur's private laboratory notebooks, which have been available to scholars only since 1971. In the end, when all the evidence is gathered and reconsidered, the popular view of him may be altered, but Pasteur will remain a human being whose unceasing effort, scientific imagination, and inspired intuition unquestionably improved the food we eat and the world we live in.

Bibliography

Debré, Patrice. Louis Pasteur. Paris: Flammarion, 1994.

De Kruif, Paul. The Microbe Hunters. New York: Harcourt, Brace, 1926. Two chapters on Pasteur.

Dubos, René J. Louis Pasteur: Free Lance of Science. Boston: Little Brown, 1950.

Duclaux, Émile. Pasteur: The History of a Mind. Translated by Erwin F. Smith and Florence Hedges. Philadelphia; London: W. B. Saunders, 1920. Duclaux was Pasteur's assistant and his successor at the Pasteur Institute.

Geison, Gerald L. The Private Science of Louis Pasteur. Princeton, N.J.: Princeton University Press, 1995.

Loir, Adrien. A l'ombre de Pasteur. Paris: Le Mouvement Sanitaire, 1938. Loir was Pasteur's nephew and lab assistant.

Vallery-Radot, Pasteur. Pasteur inconnu. Paris: Flammarion, 1954. The author is Pasteur's grandson.

Vallery-Radot, René. La Vie de Pasteur. 2 vols. Paris: Hachette et cie, 1900.

Vallery-Radot, René. M. Pasteur, histoire d'un savant par un ignorant. Paris: J. Hetzel, 1883. A short work written by Pasteur's son-in-law and corrected by Pasteur himself.

—Alice Arndt

A French scientist of the nineteenth century whose work was very important in proving that many diseases are caused by microorganisms. He developed pasteurization, in which fluids, such as milk, are heated for a specific period of time to kill harmful bacteria.

Louis Pasteur's career began by solving the outstanding problem in chemistry of his day: Why did two substances that were the same chemically react differently to light? His work for his doctoral degree, when he was only 26, led to the understanding that crystals can exist in right-handed and left-handed forms, a finding with implications that are still being worked out today. In this, as in many other enterprises, luck in choice of materials helped Pasteur. Of course, it was not fortune alone that made him a great scientist. As he said himself, "Chance favors the prepared mind."

Pasteur became the dean of chemistry at the French University of Lille in 1854. In 1856 an industrialist asked Pasteur to investigate why beer and wine often turn sour when aging. Leading chemists of the time, such as Justus Liebig and Friedrich Wöhler, believed that fermentation is a chemical reaction. Pasteur showed that both fermentation and spoiling are caused by minute living organisms. Pasteur also developed a way to prevent wine from spoiling, in a process now called pasteurization. Heating wine to about 50°C (120°F) kills microorganisms that might spoil it.

Pasteur proceeded to study interactions of microorganisms and other organic materials. He showed, for example, that boiled meat extract does not spoil unless exposed to dust particles in air. In 1865 Pasteur investigated a disease that was killing silkworms. He was not able to isolate the microorganism, but suggested killing the infected silkworms and starting up new cultures free of infection.

Pasteur had recognized that infectious diseases are caused by microorganisms. This concept soon led others to introduce sterilization, disinfection, vaccines, and eventually antibiotics.

Pasteur himself developed several vaccines, including those for rabies and anthrax. He created weakened microorganisms by heating them. They could not cause the disease but evoked immunity to these germs in patients. His work was crowned by the successful inoculation of a boy bitten by a rabid dog in 1885.

Quotes:

"Fortune favors the prepared mind."

"Let me tell you the secret that has led me to my goal, My strength lies solely in my tenacity."

"In the field of observation, chance favors only the prepared minds."

"Where observation is concerned, chance favors only the prepared mind."

"There does not exist a category of science to which one can give the name applied science. There are science and the applications of science, bound together as the fruit of the tree which bears it."

"There are no such things as applied sciences, only applications of science."

See more famous quotes by Louis Pasteur

Louis Pasteur
French microbiologist and chemist
Born	December 27, 1822(1822-12-27) Dole, Jura, Franche-Comté, France
Died	September 28, 1895 (aged 72) Marnes-la-Coquette, Hauts-de-Seine, France
Nationality	French
Religious stance	Catholic
Signature

Louis Pasteur (pronounced: [pastøʁ] December 27, 1822 – September 28, 1895) was a French chemist and microbiologist born in Dole. He is best known for his remarkable breakthroughs in the causes and preventions of disease. His discoveries reduced mortality from puerperal fever, and he created the first vaccine for rabies. His experiments supported the germ theory of disease. He was best known to the general public for inventing a method to stop milk and wine from causing sickness, a process that came to be called pasteurization. He is regarded as one of the three main founders of microbiology, together with Ferdinand Cohn and Robert Koch. Pasteur also made many discoveries in the field of chemistry, most notably the molecular basis for the asymmetry of certain crystals.^[1] His body lies beneath the Institute Pasteur in Paris in a spectacular vault covered in depictions of his accomplishments in Byzantine mosaics.^[2]

Contents 1 Early life and biography 2 Work on chirality and the polarization of light 3 Germ theory 4 Immunology and vaccination 5 Allegations of deception 6 Honors and final days 6.1 Statements 7 See also 8 Notes 9 References 10 External links

Early life and biography

Louis Pasteur was born on December 27, 1822, in Dole in the Jura region of France, into the family of a poor tanner. He grew up in the nearby town of Arbois, where he later had his house and laboratory, these are now a Pasteur museum.^[1] He gained degrees in Letters and in Mathematical Sciences before entering the École Normale Supérieure, an elite college. After serving briefly as professor of physics at Dijon Lycée in 1848, he became professor of chemistry at the University of Strasbourg,^[3] where he met and courted Marie Laurent, daughter of the university's rector, in 1849. They were married on May 29, 1849, and together had five children, only two of whom survived to adulthood, two died of typhoid and one of a brain tumor. These personal tragedies inspired Pasteur to try to find cures for diseases such as typhoid.

Work on chirality and the polarization of light

Pasteur separated the left and right crystal shapes from each other to form two piles of crystals: in solution one form rotated light to the left, the other to the right, while an equal mixture of the two forms canceled each other's effect and does not rotate polarized light.

In Pasteur's early work as a chemist, he resolved a problem concerning the nature of tartaric acid (1849). A solution of this compound derived from living things (specifically, wine lees) rotated the plane of polarization of light passing through it. The mystery was that tartaric acid derived by chemical synthesis had no such effect, even though its chemical reactions were identical and its elemental composition was the same.^[1]

Upon examination of the minuscule crystals of sodium ammonium tartrate, Pasteur noticed 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 the compound: solutions of one form rotated polarized light clockwise, while the other form rotated light counterclockwise. An equal mix of the two had no polarizing effect on light. Pasteur correctly deduced the molecule in question was asymmetric and could exist in two different forms that resemble one another as would left- and right-hand gloves, and that the biological source of the compound provided purely the one type.^[4] This was the first time anyone had demonstrated chiral molecules.

Pasteur's doctoral thesis on crystallography attracted the attention of M. Puillet and he helped Pasteur garner a position of professor of chemistry at the Faculté (College) of Strasbourg.^[3]

In 1854, he was named Dean of the new Faculty of Sciences in Lille. In 1856, he was made administrator and director of scientific studies of the École Normale Supérieure.^[3]

Germ theory

Pasteur demonstrated that fermentation is caused by the growth of microorganisms, and that the emergent growth of bacterium in nutrient broths is not due to spontaneous generation^[5] but rather to biogenesis (Omne vivum ex ovo).

Bottle en col de cygne (Swan neck duct) used by Pasteur

Institut Pasteur de Lille

He exposed 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 unless the flasks were broken open; therefore, the living organisms that grew in such broths came from outside, as spores on dust, rather than spontaneously generated within the broth. This was one of the last and most important experiments disproving the theory of spontaneous generation. The experiment also supported germ theory.^[5]

While Pasteur was not the first to propose germ theory (Girolamo Fracastoro, Agostino Bassi, Friedrich Henle and others had suggested it earlier), he developed it and conducted experiments that clearly indicated its correctness and managed to convince most of Europe it was true.^[6] Today he is often regarded as the father of germ theory and bacteriology, together with Robert Koch.^[6][7]

Pasteur's research also showed that the growth of microorganisms was responsible for spoiling beverages, such as beer, wine and milk. With this established, he invented a process in which liquids such as milk were heated to kill most bacteria and molds already present within them.^[8] He and Claude Bernard completed the first test on April 20, 1862. This process was soon afterwards known as pasteurization.^[8]

Beverage contamination led Pasteur to the idea that microorganisms infecting animals and humans cause disease. He proposed preventing the entry of microorganisms into the human body, leading Joseph Lister to develop antiseptic methods in surgery.^[6]

In 1865, two parasitic diseases called pébrine and flacherie were killing great numbers of silkworms at Alais (now Alès). Pasteur worked several years proving it was a microbe attacking silkworm eggs which caused the disease, and that eliminating this microbe within silkworm nurseries would eradicate the disease.^[8][9]

Pasteur also discovered anaerobiosis, whereby some microorganisms can develop and live without air or oxygen, called the Pasteur effect.^[10]

Immunology and vaccination

Pasteur's 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, even though they had only caused mild symptoms.^[11][12]

His assistant Charles Chamberland (of French origin) had been instructed to inoculate the chickens after Pasteur went on holiday. Chamberland failed to do this, but instead went on holiday himself. On his return, the month old cultures made the chickens unwell, but instead of the infection being fatal, as it usually was, the chickens recovered completely. Chamberland assumed an error had been made, and wanted to discard the apparently faulty culture when Pasteur stopped him. Pasteur guessed the recovered animals now might be immune to the disease, as were the animals at Eure-et-Loir that had recovered from anthrax.^[13]

In the 1870s, he applied this immunization method to anthrax, which affected cattle, and aroused interest in combating other diseases.

Louis Pasteur in his laboratory, painting by A. Edelfeldt in 1885

Pasteur publicly claimed he had made the anthrax vaccine by exposing the bacillus to oxygen. His laboratory notebooks, now in the Bibliotheque Nationale in Paris, in fact show Pasteur used the method of rival Jean-Joseph-Henri Toussaint, a Toulouse veterinary surgeon, to create the anthrax vaccine.^[4][14] This method used the oxidizing agent potassium dichromate. Pasteur's oxygen method did eventually produce a vaccine but only after he had been awarded a patent on the production of an anthrax vaccine.

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, in comparison with the naturally acquired disease. Edward Jenner had also discovered vaccination, using cowpox to give cross-immunity to smallpox (in 1796), and by Pasteur's time this had generally replaced the use of actual smallpox material in inoculation. The difference between smallpox vaccination and cholera and anthrax vaccination was that the weakened form of the latter two disease organisms had been generated artificially, and so a naturally weak form of the disease organism did not need to be found.

This discovery revolutionized work in infectious diseases, and Pasteur gave these artificially weakened diseases the generic name of vaccines, to honor Jenner's discovery. Pasteur produced the first vaccine for rabies by growing the virus in rabbits, and then weakening it by drying the affected nerve tissue.

The rabies vaccine was initially created by Emile Roux, a French doctor and a colleague of Pasteur who had been working with a killed vaccine produced by desiccating the spinal cords of infected rabbits. The vaccine had only been tested on eleven dogs before its first human trial.^[4][15]

This vaccine was first used on 9-year old Joseph Meister, on July 6, 1885, after the boy was badly mauled by a rabid dog.^[4] This was done at some personal risk for Pasteur, since he was not a licensed physician and could have faced prosecution for treating the boy. However, left without treatment, the boy faced almost certain death from rabies. After consulting with colleagues, Pasteur decided to go ahead with the treatment. The treatment proved to be a spectacular success, with Meister avoiding the disease; thus, 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.^[4]

Legal risk was not the only kind Pasteur undertook. In The Story of San Michele, Axel Munthe writes of the rabies vaccine research:

“

Pasteur himself was absolutely fearless. Anxious to secure a sample of saliva straight from the jaws of a rabid dog, I once saw him with the glass tube held between his lips draw a few drops of the deadly saliva from the mouth of a rabid bull-dog, held on the table by two assistants, their hands protected by leather gloves.

”

Louis Pasteur portrait in his later years.

Because of his study in germs, Pasteur encouraged doctors to sanitize their hands and equipment before surgery. Prior to this, few doctors or their assistants practiced the procedure of washing their hands and equipment.

Allegations of deception

In 1995, the centennial of the death of Louis Pasteur, the New York Times ran an article titled "Pasteur's Deception". After having thoroughly read Pasteur's lab notes the science historian Gerald L. Geison declared that Pasteur had given a misleading account of the preparation of the anthrax vaccine used in the experiment at Pouilly-le-Fort.^[16]

Honors and final days

His death occurred in 1895, near Paris, from complications of a series of strokes that had started in 1868.^[4] He died while listening to the story of St Vincent de Paul, whom he admired and sought to emulate.^[17][18] He was buried in the Cathedral of Notre Dame, but his remains were reinterred in a crypt in the Institut Pasteur, Paris, where he is remembered for his life-saving work.

Pasteur won the Leeuwenhoek medal, microbiology's highest Dutch honor in Arts and Sciences, in 1895.^[19] He was a Grand Croix of the Legion of Honor–one of only 75 in all of France. Both Institute Pasteur and Université Louis Pasteur were named after him.

In many localities worldwide, there are streets named in his honor. For example, in the USA: the Medical school at Stanford University, Palo Alto and Irvine, California, Boston, Massachusetts and Polk, Florida, adjacent to the University of Texas Health Science Center at San Antonio; Jonquière, Québec; San Salvador de Jujuy and Buenos Aires (Argentina), Yarmouth and Norfolk in the United Kingdom, Jericho and Wulguru in Queensland, (Australia); Phnom Penh in Cambodia; Ho Chi Minh City in Viet Nam; Batna in Algeria, Tehran in Iran, Milan in Italy and Cluj-Napoca and Bucharest in Romania.

Pasteur was ranked #12 in the 1978 edition of Michael H. Hart's controversial book, The 100: A Ranking Of The Most Influential Persons in History. However, Pasteur was promoted to no. 11, replacing Karl Marx in the 1992 revised edition of the book.^[6]

Statements

In his triumphal lecture at the Sorbonne in 1864, Pasteur said "Never will the doctrine of spontaneous generation recover from the mortal blow struck by this simple experiment" (referring to his swan-neck flask experiment wherein he proved that fermenting microorganisms would not form in a flask containing fermentable juice until an entry path was created for them).^[4][20][21]

See also

• Infection control
• Infectious disease
• Modern medicine
• Pasteur Institute
• The Story of Louis Pasteur (a 1936 biographical film).

Notes

1. ^ ^{a b c} Catholic Encyclopedia paragraph 1
2. ^ "VM/SAC, Veterinary medicine & small ... - Google Books". Books.google.com. 2007-12-29. http://books.google.com/books?id=u8FUAAAAMAAJ&lpg=PA31&ots=HEB87YS4Kj&dq=pasteur%20tomb%20mosaic&pg=PA31#v=onepage&q=pasteur%20tomb%20mosaic&f=false. Retrieved 2009-10-07. 
3. ^ ^{a b c} Catholic Encyclopedia par. 2
4. ^ ^{a b c d e f g} David V. Cohn (December 18, 2006). "Pasteur". University of Louisville. http://pyramid.spd.louisville.edu/~eri/fos/interest1.html. Retrieved 2007-12-02. "Fortunately, Pasteur's colleagues Chamberlain [sic] and Roux followed up the results of a research physician Jean-Joseph-Henri Toussaint who reported a year earlier that carbolic-acid/heated anthrax serum would immunize against anthrax. These results were difficult to reproduce and discarded although, as it turned out, Toussaint was on the right track. This led Pasteur and his assistants to substitute an anthrax vaccine prepared by a method not dissimilar to that of Toussaint and different from what Pasteur had announced." 
5. ^ ^{a b} Catholic Ency. par. 3
6. ^ ^{a b c d} Hart, Michael H. (1992). The 100: A Ranking of the Most Influential Persons in History. Citadel Press. pp. 60–61. ISBN 0806513500. 
7. ^ Ullmann 383
8. ^ ^{a b c} Ullmann 384
9. ^ Catholic Ency. par. 4
10. ^ "The Pasteur Effect". Cornell University. June 10, 2004. http://instruct1.cit.cornell.edu/courses/biomi290/MOVIES/PASTEUR.HTML. Retrieved 2007-12-02. 
11. ^ Catholic Ency. par. 5
12. ^ Ullmann 385
13. ^ Miller 278–279
14. ^ Adrien Loir (1938). Le mouvement sanitaire. pp. 18, 160. 
15. ^ Catholic Ency. par. 6
16. ^ See Gerald Geison, The Private Science of Louis Pasteur, Princeton University Press, 1995. ISBN 069101552X.
17. ^ Catholic Ency. par. 9
18. ^ "Louis Pasteur" in the 1913 Catholic Encyclopedia.
19. ^ Microbe Magazine: Awards: Leeuwenhoek Medal
20. ^ Fox, Sidney W.; Klaus Dose (1972). Molecular Evolution and the Origin of Life. W.H Freeman and Company, San Francisco. pp. 4.171. ISBN 0824766199. 
21. ^ Oparin, Aleksandr I. (1953). Origin of Life. Dover Publications, New York. p. 196. ISBN 0486602133. 

References

•  "Louis Pasteur". Catholic Encyclopedia. New York: Robert Appleton Company. 1913. http://en.wikisource.org/wiki/Catholic_Encyclopedia_(1913)/Louis_Pasteur. 
• Debré, P.; E. Forster (1998). Louis Pasteur. Baltimore, MD: Johns Hopkins University Press. ISBN 0-8018-5808-9. 
• Geison, Gerald L. (1995). The private science of Louis Pasteur. Princeton, NJ: Princeton University Press. ISBN 0-691-03442-7. 
• Latour, Bruno (1988). The Pasteurization of France. Boston: Harvard University Press. ISBN 0-674-65761-6. 
• Miller, George (1901). A Text-book of Bacteriology. Wood. pp. 278–279. http://books.google.com/books?id=uNziSqWxtBwC&pg=PA278&lpg=PA278&dq=pasteur+loir+anthax&source=web&ots=zhAyWjV5CL&sig=W-ODafIbuqkV5eE9AyI0rmpnDv8. Retrieved 2007-12-02. 
• Tiner, John Hudson (1990). Louis Pasteur: Founder of Modern Medicine. Fenton, MI: Mott Media. ISBN 0-88062-159-1. 
• Ullmann, Agnes (2007). "Pasteur–Koch: Distinctive Ways of Thinking about Infectious Diseases" (PDF). Microbe (American Society for Microbiology) 2 (8): 383–387. http://www.asm.org/ASM/files/ccLibraryFiles/Filename/000000003237/znw00807000383.pdf. Retrieved 2007-12-02. 

External links

Wikimedia Commons has media related to: Louis Pasteur

Wikiquote has a collection of quotations related to: Louis Pasteur

• The Institut Pasteur - Foundation Dedicated to the prevention and treatment of diseases through biological research, education and public health activities
• The Pasteur Foundation - A US nonprofit organization dedicated to promoting the mission of the Institut Pasteur in Paris. Full archive of newsletters available online containing examples of US Tributes to Louis Pasteur.
• Pasteur's Papers on the Germ Theory
• Pasteur's Work on Beer Brewing
• The Pasteur Galaxy
• Louis Pasteur featured on the 5 French Franc banknote from 1966.
• Germ Theory and Its Applications to Medicine and Surgery, 1878
• LIFE magazine's top 100 events of the millennium: Germ theory of disease and Pasteur
• Louis Pasteur (1822-1895) profile, AccessExcellence.org

The complete work of Pasteur, BNF (Bibliothèque nationale de France)

• Pasteur Œuvre tome 1 – Dissymétrie moléculairePDF (French)
• Pasteur Œuvre tome 2 – Fermentations et générations dites spontanéesPDF (French)
• Comptes rendus de l’Académie des sciences Articles published by Pasteur (French)

Preceded by Émile Littré

Seat 17 Académie française 1881–1895

Succeeded by Gaston Paris

Persondata
NAME	Pasteur, Louis
ALTERNATIVE NAMES
SHORT DESCRIPTION	French microbiologist and chemist
DATE OF BIRTH	27 December 1822(1822-12-27)
PLACE OF BIRTH	Dole, Jura, France
DATE OF DEATH	28 September 1895
PLACE OF DEATH	Saint-Cloud, Hauts-de-Seine, Dole

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