Thursday, January 27, 2011

Louis Pasteur: The Tenacious Scientist

Great Advances in Science

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.
Louis Pasteur
Correspondance de Pasteur 1840-1895
(1940), Vol. 1, 315

When I approach a child, he inspires in me two sentiments; tenderness for what he is, and respect for what he may become.
Louis Pasteur

Science knows no country, because knowledge belongs to humanity, and is the torch which illuminates the world. Science is the highest personification of the nation because that nation will remain the first which carries the furthest the works of thought and intelligence.
Louis Pasteur,
Toast at a Banquet of the International Congress
of Sericulture, Milan, 1876

Louis Pasteur [1822-1895]: Pasteur's deduced that if germs were the cause of fermentation, they were likely the cause of contagious diseases. Credit: Felix Nadar (1820-1910): Paris
Source: Copied from Portraits from the Dibner Library of the History of Science and Technology

Louis Pasteur's contributions to bettering humankind are among the greatest and well-known in the modern era. A French chemist and bacteriologist of the 19th century, Pasteur is famous for deriving the germ theory of disease and developing the process of pasteurization, which bears his name. Personal tragedy, the death of three of his five children, contributed to his drive to understand the causes of diseases.

At that time, it was hard to convince people, including some scientists and many doctors, that germs existed. If anything, Pasteur was tenacious and persistent, particularly if he thought he was right. Which he proved to be.

Louis Pasteur was born in Dole, France, about 400 kilometers south-east of Paris, on December 27, 1822, to Jean-Joseph Pasteur and Jeanne Roqui. His father was a tanner. It is perhaps ironic or surreptitious that the tanning process requires microbes to prepare the leather for processing. At the time Louis Pasteur was a child, few people knew about the existence of microbes, or germs. Pasteur's work as a scientist a few decades later would change all that. (A time-line can be found here.)

A few years after his birth, the family moved to the nearby town of Arbois. Pasteur completed a Bachelor of Science degree at the Royal College in Besançon in 1842, after which he studied at the École Normale Supérieure, an elite college that trained teachers for colleges and universities. Pasteur obtained his master of science degree in 1845, and earned a doctorate in sciences in 1847. His doctoral thesis was on crystallography, the study of forms and structures of crystals.

After serving briefly as teacher of physics at Dijon Lycée (a secondary or high school) in 1848, he became professor of chemistry at the University of Strasbourg. There he met Marie Laurent, daughter of the university's rector. They subsequently married on May 29, 1849, and had five children, only two of whom survived to adulthood. The other three died of typhoid. Such provided him sufficient inspiration to find how diseases formed, and to find ways to make the world safer from diseases like typhoid, which killed many.

Portrait of Pasteur: At his laboratory, 1885: By Albert Gustaf Aristides Edelfelt (1854-1905). At the Symbolisme Hall at the Musée d'Orsay, in Paris. Source:

In 1854, at the age of thirty-one, Pasteur became professor of chemistry and dean of sciences at the new University of Lille. In 1856, Pasteur returned to Paris to became manager and director of scientific studies of the École Normale Supérieure, his alma mater.

Soon thereafter he began devoting his time to some of the problems that local industries were facing. For example, one producer of vinegar from beet juice wanted to find out why the vinegar sometimes spoiled. There were similar problems with both wine- and beer-making

Pasteur then meticulously collected samples of fermenting juices and examined them under a microscope. What he noticed would change not only the way we viewed the process of fermentation, but lead to safer ways of conducting surgery, says
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.
Or, simply put, certain micro-organisms causes each kind of fermentation, and that when other microorganisms get into the liquid, they can cause the souring or spoiling. Pasteur with his elegant experiment also showed that germs not only cause milk to sour, but also cause infectious diseases. Pasteur found that he could kill many micro-organisms in wine by heating and then rapidly cooling the wine—a process now called pasteurization. 

Pasteur encouraged doctors to sanitize their hands and equipment before surgery. Before his findings, few doctors or their assistants would wash their hands or consider sterilizing their equipment. Pasteur's findings, for example, caught the attention of Joseph Lister, a British surgeon, He then developed antiseptic methods for surgery in the 1860s, which included sterilizing surgical instruments and cleaning wounds, thus leading to reducing post-operative infections and making surgery safer for patients.

Pasteur also developed a vaccine against anthrax in 1877; and in 1885 he developed the first vaccination against rabies in humans. The vaccine was first tested on animals, and with success. But they required a human to test its efficacy. On 6,1885, a young boy, nine-year-old Joseph Meister, had been bitten by a rabid dog, and was brought to Pasteur. The boy almost certainly would have died an agonizing death if nothing was done, thus Pasteur took the risk on using his untested vaccine on the boy.

As Pasteur said:
"The death of this child appearing to be inevitable, I decided, not without lively and sore anxiety, as may well be believed, to try upon Joseph Meister, the method which I had found constantly successful with dogs. Consequently, sixty hours after the bites, and in the presence of Drs Vulpian and Grancher, young Meister was inoculated under a fold of skin with half a syringeful of the spinal cord of a rabbit, which had died of rabies. It had been preserved (for) fifteen days in a flask of dry air. In the following days, fresh inoculations were made. I thus made thirteen inoculations. On the last days, I inoculated Joseph Meister with the most virulent virus of rabies."
Needless to say, the rabies vaccine was a huge success, and Pasteur became not only a national hero, but an international success His fame made it easier to open the Pasteur Institute, in 1887, for rabies research, prevention, and treatment. Donations came pouring in from all over the world. 

And so did the honors. "For his contributions to various medical fields, Pasteur was made a member of the French Academy of Medicine – one of the only men to do so who wasn’t actually a medical doctor," says

Pasteur had suffered a stroke in 1868, and complications from it contributed to his death decades later. Louis Pasteur died  in Marnes-la-Coquette, France, on September 28, 1895. He was 72.  He was initially buried in the Cathedral of Notre Dame, but his remains were re-interred in a Neo-Byzantine crypt at the Institut Pasteur in Paris in 1896.

Pasteur achieved much in his life. He once explained the secret to his success: "Let me tell you the secret that has led me to my goal. My strength lies solely in my tenacity."

Note: I am still fine-tuning the schedule for this blog, and, accordingly, I am making some small changes. Great Scientific Advances will move to Thursday from Wednesday, and now be called Great Advances in Science. In addition, I also plan to have a Guest Blogger series beginning in February 2011.

1 comment:

  1. Thank you so much for sharing.........
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