From the time of Hippocrates, it had been believed that diseases were the result of imbalances in the humors within the organism.

There was no question of the possibility that one could become ill because of small beings that were not visible to the human eye and that, moreover, were tiny. How could it be possible for someone to become ill because of something so small and, apparently, weak?

In addition to this ignorance about the spread of disease, at the time was widely shared the idea that there were annoying animals, such as flies and rats, which arose magically and without any being to beget them.

Brief biography of Louis Pasteur

Louis Pasteur

However, Louis Pasteur was able to refute these ideas, carrying out a very exhaustive investigation that not only allowed him to acquire world-wide fame but, in addition, to save thousands of lives with his findings.

Let’s see who this French chemist and bacteriologist was and what contributions he made to the world of science.

Early years

Louis Pasteur was born in a French town called Dôle on December 27, 1822.. He spent his childhood mostly in the town of Arbois, in Franche-Comté.

Although he is known today as one of the most important chemists and microbiologists in history, the truth is that the young Louis was not much given to natural sciences.

During his childhood, he showed pictorial aptitudes, in fact, his first great ambition was to become an art teacher. Chemistry was not his strong point, getting rather mediocre grades and not showing enough interest, according to his first teachers.

His father, Jean-Joseph Pasteur, who was a tanner, forced the young Louis to study at the Lyceum in Besançon, where he obtained a bachelor’s degree in letters (1840) and a bachelor’s degree in science (1842).

Professional life

After graduating from high school, he was admitted to the École Normale Supérieure in Paris.where the first year got bad grades. One year later he returned and it was from then on that he began to show interest in chemistry, thus beginning his more than remarkable scientific and professional career.

In 1847 he received his doctorate in physics and chemistry, later becoming a professor of physics at the Lyceum in Dijon and then in Strasbourg. It was there that he met his wife, Marie Laurent, with whom he had five children, two of whom reached adulthood.

In 1854 he was appointed Dean of the Faculty of Science at the University of Lille. From 1857 onwards, he held the position of director of scientific studies at the École Normale and ten years later he was in charge of the laboratory of the same institution.

In 1888 the Pasteur Institute was founded, which Louis Pasteur himself would direct until the date of his death. Louis Pasteur died of cardiorespiratory arrest on September 28, 1895 at the age of 72.

Scientific work

I wanted to be an artist when I was a kid, though, being a bit older she showed herself as a great scientist in the area of chemistry and microbiologyThis is the first of its kind in the world, offering the world great discoveries that have contributed to the reduction of diseases and their sequels.

Optical isomery

One year after his doctorate in chemistry, when he was 26 years old, Louis Pasteur was able to solve one of the great mysteries of the time.. At that time it was already known that tartaric acid came in two forms, of identical composition but with different physical properties.

The substance is synthesized by living beings, but can also be produced in laboratory conditions, only that produced by living beings was able to polarize light while synthetic was not.

The young Pasteur looked at both versions of the substance and saw that, under the microscope, synthetic tartaric acid had crystals of two types, which were the mirror image of each other.

Thus, the chemical composition of these crystals was the same, but their structure was different. This caused some crystals to polarize the light to the right and others to the left.

Observing the tartaric acid produced by living beings, he observed that there was only one type of crystal, the one that made the light polarize to the right.

2. Pasteurization

At the time, it was thought that fermentation, with which dairy products and alcoholic beverages are obtained, was a chemical process in which there was no action of any living organism.

However, Pasteur refuted this theory, since he discovered that living beings did intervene in the process, specifically two types of yeast, one producing alcohol and the other lactic acid.

After observing this, he elaborated a method with which he heated the wine up to 44º C for a short time in order to kill those organisms that could spoil the drink.

This process was what would later be called pasteurization.Pasteur, a method by which Pasteur is widely known in addition to being what allows to guarantee the safe consumption of hundreds of food products today.

3. The decline of the spontaneous generation

Before the appearance of Pasteur, it was held that there were some living beings, such as flies, worms or even rats, were suddenly generated, without the need for a parent to have conceived them.

Although this idea may sound somewhat nonsensical, at that time experiments were carried out that claimed to have proved the theory to be true, even though they had not been carried out in the most rigorous way. However, Louis Pasteur was able to refute these ideas.

His experiment consisted of introducing boiled broth into flasks. Some flasks had a filter that prevented the entry of air, while others had no filter, although the neck was very long and curved, hindering the entry of air but not preventing it.

After a while he observed that in none of the flasks, whether they had filters or not, had anything grown, demonstrating that if something grows in a place it must necessarily come from the outside, in the form of spores or contaminated dust.

So, Pasteur demonstrated that organisms do not arise spontaneously inside an isolated environment.but they had to come from outside. This is what definitely put an end to the theory of spontaneous generation.

In addition, on the basis of his findings, he formulated the principle ‘omne vivum ex ovum’, which means that every living being comes from a previous living being.

Thanks to this, he laid the foundations for the formulation of the germinal theory of diseases, in addition to cell theory and modern microbiology.

4. Germ theory and vaccination

In 1865 the south of France was suffering serious economic problems because silk production was declining. The cause of this seemed to be diseases in the silkworms, causing heavy losses.

After four years of research, Pasteur was able to observe that there were not one but two diseases affecting silkworms. One produced by parasites that attacked the worms in their initial stage, and the other produced by parasites in the leaves on which they fed.

The best option for eliminating the disease was to eliminate the worms and plants that were contaminated, making sure that those that were healthy did not become infected.

After these discoveries, delved deeper into the origin of contagious diseases.

The idea that there were diseases that could be spread by large animals and other people was accepted, especially considering historical antecedents such as the Black Death.

However, the scientific community at the time was reluctant to accept that microorganisms could be the cause of diseases manifested in living beings much larger than themselves.

From here, Pasteur developed the germinal theory of contagious diseases, according to which these diseases have their origin in a microscopic living being, which can spread among people and generate chemical processes such as fermentation and decomposition.

This refuted the general idea of the time, which was that all illness was the product of an imbalance in the moods within the body, according to the most classical view of medicine.

Although the theory was initially unpopular, it prompted many health professionals to take measures to sterilize surgical components, which increased patient survival in the postoperative period.

Based on his observations of contagious diseases, Pasteur accidentally discovered how to improve resistance to these types of medical conditions.

While investigating the mechanism of transmission of bacteria in chickens, his research team was careless in leaving the bacteria they wanted to inoculate the birds poorly stored. After a while, they decided to see what would happen if the weakened bacteria were inoculated, seeing that the birds survived despite showing some symptoms.

Although the idea that inoculating a weakened disease could produce immunity to it was reported by Edward Jenner in 1796, inoculating it into cows, it did not seem that the subject had been thoroughly investigated until Pasteur’s time. In honor of Jenner, Pasteur called this technique vaccination.

Pasteur’s opportunity to try this new technique on humans came in 1885. That year, a boy named Joseph Meister had had the very bad luck of being bitten fourteen times by a dog with rabies.

The fate of the child seemed to be sealed, since at the time the disease had no known cure and was synonymous with death in a matter of days.

Pasteur tried to see what would happen if he inoculated the rabies pathogen. Despite the legal risks, since Pasteur was not a doctor, he was successful and the child was saved..

Bibliographic references

  • Debre, P. and Forster, E. (2000). Louis Pasteur. Johns Hopkins University Press.
  • Martínez-Báez, M. (1972). Pasteur: Life and work. Mexico: Fondo de Cultura Económica.
  • Tiner, J. H. (1990). Louis Pasteur: Founder of Modern Medicine. Mott Media.
  • Vallery Radot, R. (1937) Vie de Pasteur. Flammarion