❖"A bottle of wine contains more philosophy than all the books in the world."

❖"An individual who gets used to hard work can thereafter never live without it. Work is the foundation of everything in this world."

A French chemist and microbiologist, Louis Pasteur is called the Father of Microbiology. He is remembered for his pioneering research in identifying the causes of diseases and suggesting ways to prevent them. He discovered the principles of vaccination, microbial fermentation and developed the pasteurization process.

Born in Dole, France, on December 27, 1822, into the family of a poor tanner, Louis Pasteur was average in studies, but was gifted in drawing and painting. He was a hard worker, and attained his BA and B Sc degrees from Collège Royal de Besançon, Paris, and earned his doctorate in the year 1847.

For many years of his life, Louis Pasteur was teaching and carrying out research at Dijon and Strasbourg, when in 1854, he moved to the University of Lille, and became a chemistry professor.

Louis Pasteur started his work as a chemist by studying crystallography, which was an emerging branch of science at that time. His project involved the crystallization of various organic compounds.

He started with tartaric acid, the crystals of which are present in the deposits of fermenting wine. A second acid sediment called paratartaric acid or racemic acid are also found in wine barrels. Their structures were identical. However, in solution, tartaric acid rotated a beam of polarized light to the right, whereas paratartaric acid did not.

This puzzled and convinced him that there was some difference in the internal structure of the compounds. After intense examination, he discovered no difference in tartaric acid crystals. However, for paratartaric acid, he found two types of crystals which were mirror images of each other. Thus, he founded a new branch of chemistry called stereochemistry.

Pasteur proposed that this asymmetry plays a role in living beings, and they produce molecules of only one specific orientation. This fascinated him, and he began his studies on fermentation of alcohol.

Louis Pasteur had two great passions - his love for wine, and the scientific methods. Pasteur demonstrated that fermentation is a result of the growth of microorganisms. He was called upon to tackle the spoiling of wine and beer, that surmounted to great losses by the French beverage industry.

Pasteur found that after aging properly, the wine contained yeast cells. The spoiled wine was sour to taste, because of the presence of bacterial cells that produced lactic acid. He suggested heating the wine gently at about 120 °F, and then cooling it to destroy the bacteria. He also suggested maintaining proper cleanliness to avoid the spoilage of wine.

This method of killing microorganisms is called pasteurization. He introduced the concept of anaerobic respiration - the process which takes place in the absence of oxygen, but still involves living things like yeast. Over the next few years, he identified the microorganisms responsible for the fermentation and spoiling of wine, beer, and vinegar.

Louis Pasteur believed in hard work and perseverance. He continued with his work on microorganisms and their existence. The spontaneous generation of life, according to which, life could arise spontaneously from decaying matter was a notion at that time. However, after his work on fermentation, Pasteur decided to find an answer for this.

He showed that beef broth when heated in a 'swan-neck' flask, is sterilized. This flask has a long neck which prevents dust particles as well as other contaminants from reaching the body. However, if the broth was exposed to air, then it became cloudy with the presence of microorganisms. Thus, he contradicted the theory of spontaneous generation.

He applied the same theory of spoiling of the beverages because of microorganisms, to human diseases as well. He hypothesized that, if fermentation was caused by germs, then the cause of contagious diseases was also the same. His hypothesis proved valid, after he studied the disease that affected silkworms, anthrax, and chicken cholera.

In 1865, a devastating mysterious disease was destroying the silk industry in France. He proved the presence of microbes that were causing the disease, and suggested the elimination of all the unfit silkworms.

Pasteur enabled a method of selection of healthy silkworm eggs and their preservation. It prevented the spread and contamination of the disease-causing microbes, and thus, saved the silk industry from a major disaster.

The first disease that Pasteur developed a vaccine for was chicken cholera. It was by chance that he found out that cultures of chicken cholera lost their infective characteristics and were attenuated over generations. After inoculating chickens with attenuated form of pathogens, they became resistant to the virulent form, and did not contract the disease.

He applied the same method to the anthrax disease in sheep. After inoculating the attenuated form of the bacillus, the sheep were vaccinated. The experiment was a huge success, and convinced many people about the validity and credibility of Pasteur's experiments.

After his success with animal diseases, he turned his focus on human diseases. Rabies was a dreaded disease at that time. Pasteur was unable to view the disease-causing microbe (now we know it's a virus) under a microscope. He developed new methods to tackle the disease, and chose rabbits for his experiments.

In his experiments, he developed the rabies vaccine from the spinal fluid of these infected rabbits. In 1885, the vaccine was first tested on a nine-year-old boy, Joseph Meister, who was bit by a rabid dog. After receiving a series of shots of the new vaccine, the boy did not develop any deadly symptoms of the disease. Thus, he was vaccinated against rabies.

The success of the rabies vaccine brought him fame and recognition, which was well-deserved. Along with monetary gains, and help from an international fundraising campaign, the Pasteur Institute was built, which was inaugurated on 14 November, 1888. It is now one of the most recognized institutions in the world.

Louis Pasteur passed away on September 28, 1895. Already a French hero, he was buried at the Notre-Dame Cathedral. Later, his remains were transferred to the Pasteur Institute in Paris.

His works revolutionized medicine. He introduced sterilization and cleanliness techniques in medical science, to prevent infection and diseases. His principles and experiments laid the foundation of immunology, which were later used by other scientists and researchers. One of the greatest scientists of our time, he laid the foundations of health and science.