Louis Pasteur – Contributions
Louis Pasteur (27 December 1822 – 28 September 1895) was a French chemist and microbiologist renowned for his discoveries of the principles of vaccination, microbial fermentation, and pasteurization, the last of which was named after him.
Pasteur was responsible for disproving the doctrine of spontaneous generation. Louis Pasteur showed that microbes were omnipresent – in water, in air, on objects, on the skin – and that some were responsible for diseases.
In 1862 Louis Pasteur was able to claim that:
- airborne dust contained microorganisms which develop and multiply.
- even the most putrescible liquids remained unadulterated if kept away from air (and hence these microorganisms) after heating.
He recommended ways of preventing and fighting these germs. This notably included the use of aseptic procedures. He advocated the importance of sterilization of linen and dressings, passing instruments through a flame and clean hands.
How does fermentation work?
While studying butyric fermentation he discovered a new class of living organisms capable of living without air. He used the term ” anaerobic ” to describe ferments able to live without air and ” aerobic ” for microorganisms requiring the presence of free oxygen to grow. He came to the conclusion that fermentation is the consequence of life without air.
His research, which showed that microorganisms cause both fermentation and disease, supported the germ theory of disease at a time when its validity was still being questioned. Thus, Pasteur is also regarded as one of the fathers of germ theory of diseases. His many experiments showed that diseases could be prevented by killing or stopping germs, thereby directly supporting the germ theory and its application in clinical medicine. He is best known to the general public for his invention of the technique of treating milk and wine to stop bacterial contamination, a process now called pasteurization.
Louis Pasteur used the infectious agents themselves to achieve immunization. The processes were then applied to numerous diseases such as cholera (1878) and anthrax (1881). He developed his method for attenuating microbial virulence for fowl cholera, ovine (sheep) anthrax, and for erysipelothrix infection.
Despite the satisfactory results with dogs, Louis Pasteur feared testing it on humans. On the morning on July 6, 1885, Louis Pasteur was given the opportunity to overcome his fears and test his treatment on humans when Joseph Meister was brought to him. The nine-year-old boy from Alsace had been bitten by a rabid dog fourteen times.
As Louis Pasteur was not a physician he requested Dr Grancher to inoculate the child. In the space of 10 days, Joseph Meister received a total 13 injections of rabid spinal cord that were progressively fresher (more virulent). This first vaccination was a success. Joseph Meister never developed rabies and became the first ever human being to be vaccinated.
In September 1885, Jean-Baptiste Jupille, a 15-year-old shepherd, arrived at the Ulm street laboratory. He had been severely bitten by a rabid dog who had attacked six other shepherds. Jean-Baptiste Jupille had jumped on the dog to allow his friends to escape.
Louis Pasteur administered his treatment and was successful again. Soon, vast numbers of people bitten by rabid animals came from all over France. Given the numbers, Louis Pasteur set up a special rabies vaccination clinic, which also doubled as a research and teaching center.
Three years later the Pasteur Institute opened its doors. The Institut Pasteur was opened on November 14, 1888 following Louis Pasteur’s successful international appeal for funds. He now had the facilities to extend vaccination against rabies, continue research on infectious diseases and share the resulting knowledge.
Disease-Environment Interactions: Another Contribution of Louis Pasteur
Pasteur’s earlier experiments had consistently shown that it was not difficult to infect mammals with B. anthracis, but chickens seemed to be particularly resistant to the infectious agent.
Pasteur had already discovered that B. anthracis germs did not survive well at elevated temperatures, and this finding set the stage for another one of his famous experiments. Humans maintain a core body temperature of roughly 37°C, whereas the core temperature of birds is higher, around 40°C. Pasteur reasoned that the higher body temperature of chickens might be responsible for their resistance to B. anthracis.
To test this idea, the feet and legs of two chickens were fastened to the bottom of a bucket and roughly a third of the hens’ bodies were submerged in ice cold water: a gray one was subjected to only the cold and a chicken with white feathers was inoculated with B. anthracis. Another chicken with black feathers received twice the dose of bacteria but it was not placed in the bucket of ice water, instead remaining in a comfortable thermal environment. Only the chicken with white feathers died of anthrax; whereas the gray and black hens remained healthy.
In Pasteur’s chickens, B. anthracis alone did not induce anthrax. Neither did cold stress alone cause anthrax. Instead, both cold stress and B. anthracis were required to induce the disease. Thus, he demonstrated that interactions between pathogenic microbes, host and host environment can be crucial in the etiology of disease.
“Science knows no country, because knowledge belongs to humanity, and is the torch which illuminates the world.”
“It is not the germs we need worry about. It is our inner terrain.”
“Where observation is concerned, chance favors only the prepared mind.”
“Inspiration is the impact of a fact on a well-prepared mind.”
“As in the experimental sciences, truth cannot be distinguished from error as long as firm principles have not been established through the rigorous observation of facts.”
“Let me tell you the secret that has led me to my goal. My strength lies solely in my tenacity.”
“To know how to wonder and question is the first step of the mind toward discovery.”
“The more I study nature, the more I stand amazed at the work of the Creator. Science brings men nearer to God.”
“Do not let yourself be tainted with a barren skepticism.”
“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.”
“A bottle of wine contains more philosophy than all the books in the world.”