Louis Pasteur was the chemist who has gonedown in history as one of the fathers of microbiology. He is famous for several accomplishments thatchanged science as we know it, including the pasteurization process of killing bacteriafrom liquids, and paving the way for immunology by creating life-saving vaccines. These accomplishments are just the tip ofthe iceberg, because without Pasteur’s revolutionary germ theory, modern medicine would not beanything like it is today. On this episode of Biographics, we are talkingabout the life and work of Louis Pasteur, and why he was one of the greatest minds inhistory. Early Life and EducationLouis Pasteur was born in France on December 27, 1822. He was raised in a town called Arbois by hisparents, Jean-Joseph Pasteur, and Jeanne Etiennette Roqui. His father served as a sergeant major duringthe Napoleonic Wars, and received the Legion of Honor. After the war, Jean-Joseph worked as a full-timeleather tanner, like generations of Pasteur men before him. Even though this was the family business,Jean-Joseph did not want to force his own son to carry on the tanning trade, and wasopen to allowing him to find his own passion. Usually, when we hear stories of accomplishedacademic minds like Louis Pasteur, we imagine that they may have been a genius all theirlives. In reality, young Louis was a very averagestudent in school. As a young man, he was actually far more interestedin sketching works of art than reading his textbooks. He spent a lot of his time drawing and painting,using the Jura Mountains as his inspiration. Louis Pasteur’s father encouraged him tofollow his passion for art, and considered the endeavour to be just as valuable as academicgoals. Jean-Joseph always encouraged Louis to readas many books as possible so that he remained curious about the world around him. As a veteran, he also instilled a sense ofnational pride in Louis, and duty to the people of France. Since he spent most of his young life daydreamingand sketching, Louis actually fell so far behind academically, that he had to receivea lot of tutoring at Collège d'Arbois, which is where he went to secondary school beforehe attended university at the École Normale Supérieure in Paris. This is where he began taking classes in science. Chemistry became his new passion, and he hadthe goal of earning his PhD. In 1847, he received his doctorate degree,and this set the course for the rest of his life. A Career in ChemistryWhile he was earning his PhD, Louis Pasteur taught chemistry at a secondary school calledDijon Lycée before he became a research chemist at the University of Strasbourg. When he was just 25 years old, he alreadymade discoveries that became vital in developing vaccines in the future. Microscopes had existed for hundreds of yearsbefore Louis Pasteur was born, but new improvements on the machine helped scientists to discoverthe existence of microorganisms. Louis Pasteur was far from the only scientistto be studying microorganisms at the time, but he was one of the very first. He is widely considered to be one of the “fathers”of the field that would later be called “microbiology.” In 1849, Louis Pasteur was attempting to solveissues that wine makers were having while fermenting grapes. Some batches of wine would go sour very quicklywhile others were not, even when the ingredients and process were exactly the same every time. Wine makers could not figure out why thiswas happening. Pasteur was able to gather tartaric acid,which is one of the chemicals present in the sediment of the wine during the fermentationprocess. After dissolving the tartaric acid, Pasteurwas able to pass polarized light through the sample in order to observe it. He discovered that there was a nearly-identicalcompound known as “paratartaric acid” in the wine sediments. Every other scientist who had observed thesame samples assumed that the chemical was the same, because it has the same compositionas tartaric acid. However, while these molecules seem identicalat first, they are actually mirror images of one another. You can think of it as being either left orright-handed versions of the same chemical, with one of them causing the grapes to gosour. Today, this process that Pasteur discoveredof finding the mirror version of a chemical compound is known as “molecular chirality”,and it is actually extremely important in pharmaceutical chemistry, because a left-or-righthanded version may react completely differently once it is metabolised in the human body,even though it has the same chemical composition. His discovery in the variations between thestructure and shape of a molecule also led to the field of stereochemistry. With just this one discovery, Louis Pasteurwas able to fix a problem, and also pave the way for future scientists in several fieldsof chemistry. This alone would have been a huge accomplishmentthat would have put his name down in history, but he was far from finished with his life’swork. Personal LifeLouis Pasteur met his future wife, Marie Laurent, while he was working at the University ofStrasbourg. Marie was the daughter of the school’s rector,so she spent most of her life in an academic environment. She worked in the school’s laboratory, andwas assigned as Louis Pasteur’s lab assistant and “amanuensis.” This is someone who writes down the scientificinformation, and assists in making sketches of his discoveries. Marie was a very well-educated woman, andshe would have had a lot of scientific background knowledge in order for her to understand andrecord the information. If she was born in a different time, thereis no doubt that she would have been a full-fledged chemist as well. French society at the time found it to beinappropriate for women to become scientists. But Marie and Louis respected one another,and the two of them were truly devoted to this work. It only makes sense that they were perfectfor one another both inside and outside of the laboratory. Louis Pasteur was 25 years old when he madethe discoveries in wine sediments, and the two of them were able to share the victoryof a job well done. This would be only the beginning of theirteamwork. The two were married on May 29, 1849. Louis Pasteur was 26, and Marie was 23. As the years went on, Marie continued to assistLouis in his experiments. Without her knowledge and professionalismby his side, he may not have been able to accomplish as much as he did in his career. They went on to have five children together,but tragically, only two would survive childhood. As parents who lost three children, they knewthe pain that all parents feel when their children die from a disease that could havebeen prevented, if only there was a vaccine that existed to help them. The two of them became determined to devotetheir careers to saving the lives of other children, and they were eventually able toaccomplish just that. Germ Theory and PasteurizationBefore he could begin studying diseases, Louis Pasteur still needed to do the scientificresearch that was paying the bills. In 1854, Pasteur became a chemistry professorat the University of Lille, and he was paid to continue researching issues in alcoholmanufacturing. He became the Dean of the Science department,as well, and helped to mentor the rest of the faculty. In 1861, Pasteur discovered anaerobiosis,which is crucial in understanding how yeast and sugar formed alcohol during the fermentationprocess. Even though fermentation had been going onfor thousands of years of human history, no one else had been able to explain the “how”and “why” of the chemical process. So, today, everyone running a hipster microbreweryhas Louis Pasteur to thank for their careers making craft beer. Once he fully understood the fermentationprocess, Pasteur had a theory that these invisible organisms called “germs” and “bacteria”were responsible for causing wine, beer, and milk to go sour. He proved that by boiling these liquids, hecould kill the bacteria, and then cool to it to make it drinkable again. The first successful test was completed onApril 20th, 1862. That process of heating and cooling was namedafter him; so it is now known as “pasteurization”. It is still used today. Louis Pasteur was able to move on from thefood industry, and begin studying disease, which had been his goal. In 1865, he was able to prove that microbeswere causing a disease that destroyed silkworm eggs. His wife, Marie, assisted him in growing thesilk worms, and keeping them alive during the course of the experiment. He was able to develop a prevention for contamination,and saved the silk-making industry around the world. So, aside from our clean wine and beer, wealso need to thank him for our fancy silk robes and pajamas. Once he was beginning to understand how bacteriacaused illnesses, he was beginning to come up with his “germ theory”. For the majority of human history, peopledid not know about the existence of germs, and they did not fully understand the immunesystem. The widely-held belief was the “Miasma Theory”,which was that diseases are caused by a poisonous vapor in the air that only came out at night. Yes, it sounds truly ridiculous in retrospect,but people had absolutely no idea how or why human beings contracted illnesses. In hospitals, doctors and nurses never evenbothered to wash their hands, because they truly did not understand the spread of disease. Human waste would sometimes make its way intothe water system, which would trigger huge outbreaks of infectious disease, all becausepeople did not understand that germs existed. Other scientists had proposed a germ theorylong before Louis Pasteur, but it was often dismissed. People had believed in Miasma Theory for solong, it had become the truth. In England, a scientist named Dr. John Snow(Not to be confused with the character from Game of Thrones) was able to save London fromthe cholera outbreak by convincing the town to shut down a water pump that had been infectedby human waste. Louis Pasteur would have probably read aboutSnow’s breakthrough in bacterial research, and it would inspire him to push the germtheory as well. Soon enough, Pasteur and the other fathersof microbiology were able to prove that the Miasma Theory was nothing but a fantasy, andthe acknowledgement that germs existed would change the medical industry was we know it. The Accidental Invention of VaccinesIn 1868, Louis Pasteur was just 46 years old when he suffered a severe stroke, and he becamepartially paralyzed. Instead of going to a hospital, Pasteur wastreated in his home. Sixteen leeches were placed behind his earsto clear the blood that had pooled around his cerebral hemorrhage. After the doctor left with the leeches, LouisPasteur was left in his wife Marie. He was very lucky that she had such an extensivescience background, because she helped to rehabilitate him to overcome his paralysis. This story is usually glossed over in manyof the history books. We tend to glorify the major accomplishmentsof successful people, and ignore the struggles. Louis Pasteur was still very human, and recoveringfrom a stroke is never an easy task. Back in the 1800’s, a stroke would likelymean death, or permanent paralysis for the rest of his life. Marie nursed him back to health, and encouragedhim to heal so that they could both return to the laboratory in order to continue theirlife’s work of curing diseases. Even though his health recovered, it wouldbe years before Louis Pasteur was able to make another major scientific discovery. Eight years later, in 1876, Louis Pasteurmade his first major breakthrough since having his stroke. At the time, scientists believed in the ideaof “spontaneous generation”. This was the ridiculous notion that livingcreatures could spontaneously generate from inanimate substances. People believed that living creatures were“born” asexually, like mice forming in rotting food, food and frogs emerging fromthe mud. This belief was so common, there were evensome scientific papers claiming to come up with a “recipe” for growing your own mice. Pasteur publicly denounced this age-old beliefof spontaneous generation, but there were still plenty of people who had their doubts. In the past, other scientists like FrancescoRedi had attempted to prove that spontaneous generation was not real. He sealed a piece of meat in a jar with alid, proving that as long as flies did not land on food, larva did not appear. However, people did not believe this, becausethey thought oxygen may be necessary for the so-called “recipe”. The only way Pasteur was able to convincethe public that animals are not born out of food was to design custom swan-necked bottlesthat curved in such a way that allowed oxygen to get through, but it would be impossiblefor flies to crawl inside. He boiled beef broth, and left it inside thisswan neck bottle. Finally, the idea of spontaneous generationwas debunked. Two years later, in 1878, Pasteur was studyingdiseases when he accidently exposed chickens to an attenuated culture of chicken cholera. However, the chickens did not die from thedisease. In fact, it had the exact opposite. When they were later exposed to the full-fledgedchicken cholera virus, they had become immune. This was his very first vaccine. At the time, the idea that he could replicatethese results in human beings was still years away from actually happening. But he theorized that if he could replicatethat same process, he just may be able to create vaccines for some of the deadliestdiseases of the time, like anthrax, tuberculosis, smallpox, and anthrax. A year later, in 1881, Louis Pasteur developeda vaccine for Anthrax, and cured several sheep in his laboratory from the disease. Even after conducting the same experimenthundreds of times, the scientific community still did not believe Louis Pasteur’s results. Even when everyone mocked and ridiculed him,he did not back down, because he knew that he was right. For years, people refused to believe him,until he traveled to the town of Pouilly le Fort, which had a farm filled with sheep thathad been infected with Anthrax. Pasteur injected his vaccine into all of thesick sheep in front of a large crowd of people. Sure enough, all of the sheep recovered, andthe newspapers finally declared that he truly had invented the cure. He once wrote this advice to future generationson how to deal with haters; “Do not let yourself be tainted with a barren skepticism.” After Louis Pasteur’s germ theory was publishedin academic papers, and there was a significant amount of proof that his animal vaccines wereworking. Educated people with open minds understoodthe concept of bacteria, and they began to make efforts to improve public health andsafety in France. Following Louis Pasteur’s discoveries aboutgerms, a politician named Eugene Poubelle began enforcing the first garbage cans inParis in 1884. At first, citizens were outraged that theycould no longer throw their trash wherever they wanted. Despite dealing with all of the skepticismand push-back from the public, Poubelle continued to mandate that garbage cans were necessaryin every home. Today, we take garbage cans for granted, butthis was a huge step in disease prevention. Over the next few years, the spread of diseasebegan to fall dramatically in France, and other countries around the world began tocopy the idea. However, just like every other scientificdiscovery in human history, there were people who still refused to believe in the germ theory,despite all of the proof that was out there. Pasteur had plenty of critics who still triedto claim that he was incorrect. Louis Pasteur had a bitter rivalry with anotherscientist named Antoine Béchamp, who completely dismissed his germ theory. Instead of believing in the existence of germs,Béchamp published his own theory of “pleomorphism”. But, of course, the truth always has a wayof coming out, and Pasteur continued to be the one who came out on top. The Rabies VaccineLouis Pasteur continued to prove to the world that his germ theory was correct, and thatinfections were the cause of disease. At the time, rabies and anthrax were bothvery serious problems in animals. If a dog was infected and bit someone, itwas guaranteed that they would die an excruciatingly painful death. After years of overcoming so much doubt inthe scientific community, Louis Pasteur was now well regarded for his achievements inscience and medicine. In 1873, The Académie de Médecine electedto bring him on as an associate member of their society. And in 1882, he was accepted into the AcadémieFrançaise. While he was doing his research there, hedecided to devote his research to curing rabies. In 1883, Pasteur was creating the rabies vaccineby acquiring rabbits that had been infected by the virus, and attempting to inject thevaccine into dogs. After trial and error, he was able to curedogs who had been infected, and bring them back to health. But using the vaccine on a human being hadnot been done until 1885. On July 6th, a 9-year old boy named JosephMeister was brought to Louis Pasteur in Paris. His parents had traveled for two days fromAlsace after he was bitten by a rabid dog. At first, Pasteur hesitated, because he hadonly ever experimented with the vaccine on dogs. But the boy was going to die anyway, so Pasteuragreed to try. He took an emulsion from the spinal cord ofa rabbit who had rabies, and formed a vaccine. The process did not happen overnight. Over the next 10 days, Joseph was given 13more injections of the vaccine, and he was hospitalized for three months. After the boy made a full recovery, LouisPasteur became famous around the world for finding the cure. On the 20th of October that same year, anadult male who had been infected with rabies six days earlier was brought to Louis Pasteur. He repeated the same vaccination process asbefore, and the man made a full recovery. Now, there was no doubt that the vaccine trulyworked. In 1886, Louis Pasteur began to treat over350 patients who had been infected with rabies in Europe and the United States. Louis Pasteur’s wife, Marie, traveled theworld with him, and nursed the sick children with rabies for months at a time while herhusband was preparing the vaccines and giving the injections. Of course, today, this same vaccine is whathelps keep our dogs and cats safe from rabies. No matter where he went, whether he couldspeak the language or not, the story was always the same. He was very proud that he was able to accomplishthis on behalf of France. He said, “Science knows no country, becauseknowledge belongs to humanity, and is the torch which illuminates the world. Science is the highest personification ofthe nation, because that nation will remain the first which carries the furthest the worksof thought and intelligence.” During this process of meeting and healingover 350 people, Pasteur got to know many of his patients. Many of them were young children who werebitten when playing with their dogs. He said, “When I approach a child, he inspiresin me two sentiments; tenderness for what he is, and respect for what he may become.” Louis Pasteur wanted to save the lives ofthese sick children so that they could have a chance to grow up, and he wanted his vaccinesto do the same for future generations all over the world. Finally, he was recognized as a scientistworthy of his own research facility, and a fundraising campaign began to create the PasteurInstitute in Paris. This was finally inaugurated on November 14,1888. When he turned 70 years old, he was givena spectacular birthday party at The University of Paris, and some of the most prestigiousdoctors and scientists were there to celebrate his life and works. Louis Pasteur he died in 1895, at the ageof 73. His body is now in a crypt in the PasteurInstitute. But his work has lived on far after his passing. Today, we still use pasteurization in thefood industry, and his breakthroughs in medicine were just the beginning. Other scientists began to use the same methodsto create vaccines for diseases that had once killed thousands of people. There is no telling just how many millionsof people would have died without the work he was able to accomplish.