• Microbigals

The Experiments of Louis Pasteur: From Germ Theory to Vaccine Creation


Professor Xi in his classroom about to start his lecture on "The Experiments of Louis Pasteur"
Who is the greatest scientist of all time? Albert Einstein? Marie Curie? Charles Darwin? All are absolutely brilliant but did any of them save as many lives as the great Louis Pasteur? I’d argue not, but who is Louis Pasteur? Outside pasteurization, do you know who Louis Pasteur was, how he impacted the Giant's lives? our lives?

His expertise goes far beyond pasteurization. Louis Pasteur was the king of crystals and chirality, famous for his fermentation facts, the stopper of spontaneous generation theory, Lister’s inspiration of antiseptic technique, the savior of the silkworms, protector of milk, beer, and wine through his protocol of pasteurization, the genius behind germ theory and the voice for vaccines at a time where microbiology was barely a field of research.

Welcome Class, welcome! Now I’m so excited to hear about your presentations today on the experiments of the great Louis Pasteur!

Experiments of Louis Pasteur


The early experiments of Louis Pasteur were in the field of chemistry, mostly looking at crystal shapes. However, in the 1850s, his focus shifted a little bit to ask why milk would sour. Convinced it was a living entity responsible, he turned to debunk the theory of spontaneous generation. The current thought of the day was that life spontaneously generated from non-living dirt or dust.


Now, who did the report on Louis Pasteur's experiment on the swan neck flask? Great Mia let’s hear it!

Swan Neck Flask Experiment of Louis Pasteur


Hi everyone, this is my report on Louis Pasteur’s Swan Neck Flask Experiment. What Louis Pasteur did to debunk the theory of spontaneous generation was brilliantly simple. The swan neck flask experiment of Louis Pasteur worked like this: he obtained 250-milliliter flasks with a swan neck or a long curved neck at the top. He filled them with a suspension of yeast and water and boiled the water, boiling the poor yeast alive! He then immediately sealed off the flasks so nothing could disturb the contents within. For half the flasks he broke off this swan neck, exposing it to the air, making a little pool party for the other air microbes. The other half had no access to the outside world, it was fully and completely contained, a yeast cemetery. If spontaneous generation was a thing, then both flasks should be teaming with life. What this experiment of Louis Pasteur’s found instead, was only life showed up in the flasks exposed to air. Microbes did not arise from spontaneous generation but from the air. This is how Louis Pasteur debunked the idea of spontaneous generation and one of his first microbe moments!


Cartoon drawing of Professor Xi's class where Mia is giving a presentation on Louis Pasteur's experiment on how Louis Pasteur disproved spontaneous generation with the use of swan neck flasks


Very nice Mia! Thank you for that wonderful presentation. Hugo, you're up!

Silk Worm Experiments of Louis Pasteur


Silkworms are these giant creatures! Bigger than tardigrades! Bigger than even the largest amoebas and the giants like to steal from them this substance they call silk to make clothes and stuff so they aren’t naked. To giants, this is a very rich and luxurious fabric and Louis Pasteur was tasked with saving these creatures.


In 1849, the great silkworm pebrine pandemic would break out. This disease would give its victims tiny dark spots like pepper all over their bodies. By 1865, the silk industry was in tragic disarray, the whole industry was collapsing and the prices of silk skyrocketed. The giants were very scared. By 1865 it was only the Japanese silkworms that did not contract the disease.


Louis Pasteur was tasked with saving the silkworm industry from certain ruin. He started with observations; he called for a healthy set of silkworms to view side by side to the diseased ones. And this is where another great revolutionary idea struck Louis Pasteur. He hypothesized that maybe diseases were infectious, a sick person can give a disease to a healthy person. So in the case of the silkworms, all they needed to do was to dispose of all the sick silkworms and thoroughly clean the cages and then start a new colony with healthy silkworms. So all the silkworms in all the land were killed and healthy silkworms were brought in to start new colonies. As long as none of them carried the disease it would not spread throughout the colonies!


Cartoon drawing of Professor Xi's class where Hugo is giving a presentation on Louis Pasteur's experiment on silk worms


Excellent Hugo. I don’t know why you are so nervous you did a splendid job! Larry Why don’t you give us your presentation Next…

Ummm, Professor Xi, actually my Tardigrade ate my homework….
Really, Larry, this is the fourth time this semester! You really need to train your tardigrade better.


Well, if it's worth any points. I’d just like to say Louis Pasteur was like a juggler. He was doing the cholera thing, the alcohol thing, that silkworm thing Hugo was just talking about and he did some things with sheep.

Louis Pasteur's face on a juggler . He is juggling a sheep, a bacteria, a glass of wine and a silk worm as these were all the host of experiments of Louis Pasteur

Well, Larry, I don’t think that was much of a report…I’m disappointed in you Larry we’ll talk after but for the benefit of the class let me explain a little on Louis Pasteur’s Experiments revolving with Cholera, which also has a very important history for the Giants regarding the start of the field of study immunology, but that’s a different man at a different time.

Cholera Experiments Of Louis Pasteur

Being not only a great scientist but also one of only a handful of people in the world that could handle microbial research, Pasteur found himself juggling a slew of pandemics all at once. While working on the silkworm pandemic, another pandemic arose, this time it would be Cholera. In the 1860s through the 1870s, the fourth pandemic of cholera began in the Bengal region. Through wars, travel, and pilgrimage, this cholera quickly spread through the middle east, Africa and Europe. By October 1865, nearly 200 people would be dying daily from this outbreak. Now at this time, Vibrio cholerae, the microbe that causes cholera was not known. However, Jon Snow has come and gone and debunked the theory of miasma. Jon Snow concluded that cholera was infectious from the water but he never linked the disease to Vibrio cholerae. Louis however, was this clever, he knew cholera must be linked to a microbe but to which one. He attempted over and over again to find the causal agent of the disease, but the elusive microbe slipped through his grasp. This Microbe Moment was meant for another.


Professor Xi, was that even a fair one to give me. He didn’t even do anything!
Well, Larry, neither did you. Now, Anna. Why don’t you introduce us to Louis Pasteur’s brave leap into the medical world!

Medical Microbiology Experiments of Louis Pasteur


Ok. Well during this time, antiseptics were only just starting to be used in hospitals and medical doctors hated microbiologists and scientists like Louis Pasteur. They thought they were better than everybody else. They didn’t think microbiology was important to their field. Dumb Doctors!


Cartoon drawing of Professor Xi's class where Anna is giving a presentation on Louis Pasteur's experiments and time in the medical field

No Anna, just because they didn’t know about the importance of microbes doesn’t mean they were dumb. They lacked information to make an educated decision.
(aside) I still think they are dumb.

Anyways, this greatly stunted the medical field and ultimately caused a lot of unnecessary deaths. But Louis Pasteur would help change the relationship between medical doctors and scientific ones.


In 1873, Pasteur befriended Alphonse Guerin who worked in a hospital and helped preach Pasteur's principles into hospitals. Joseph Lister, another famous medical man of the time, also took Pasteurs teachings to heart. The principles were quite simple and rule we still follow today and similar to the rules that Florence Nightingale was advocating for. Basically, they preached for cleanliness within hospitals, antiseptics within operating theaters, and to change bandages less frequently to prevent harmful microbes, like the society's top 10 criminals from infiltrating the wound. This ultimately seems like a no-brainer, but like I said, back then it was quite controversial because they were dumb doctors.


Very nice Anna, but next time perhaps we can give the report with a little less personal opinion and just the facts.
Fine (eyes rolled)
Great that leaves Julian and Psydney left. Who’d like to go first?
I’ll go Professor Xi.

Excellent Julian. Please go ahead.

Agricultural Experiments of Louis Pasteur


I did my report on Carbon, but not the yummy food, the disease. I couldn’t really find why it was called Carbon or how it changed its name to anthrax in the Giants’ world but Louis Pasteur did some experiments on it. I also didn’t prepare a visual….sorry but here’s my report.


Anthrax is caused by the bacteria Bacillus anthracis and is a Gram Positive rod-shaped bacteria that is found in soils. It can form spores and be dormant for years before becoming active. The toxins this bacteria produces can be fatal for both Giants and animals. During Louis Pasteur's time agricultural incidents of death could be anywhere from 10-50% so this microbe has a heavy economic cost if livestock contracted the disease. It was during this time that Louis Pasteur coined the term, “Microbe”!


Julian, is that it? Do you not have an experiment to present to the class.

Errrmmm….no…Professor, I don’t. But I did more than Larry!

Hey! I did it. I drew that awesome picture of Louis Pasteur juggling….my tardigrade just ate my homework.

Now class, settle down. Julian, why don’t you join Larry and I after class. Last but not least, Psydney you are up!

Louis Pasteur’s Journey To Vaccine Development


Hi everybody, so I did my report on Louis Pasteur’s like greatest achievement. He was the man! Like he was the man that first developed the vaccine! That’s HUGE!


As we’ve heard, Louis Pasteur’s experiments brought him to so many different areas of microbiology from environmental, to industrial, to medical to agricultural, Louis Pasteur was studying it all. He was doing all the things. But it would not be until his time studying fowl cholera, not like pee-ew cholera but like bird cholera, that an idea would strike him that would ultimately save countless lives, like probably every giant alive today!


So, one day Louis Pasteur was sent a present life Godfather style, he was sent a rooster head and was asked to investigate fowl cholera. He had to start with the basics. Like he didn’t know anything man. He was like: What causes the disease? How does the causal agent live, what does it like to eat, where does it like to live? How does disease progression work?


He tried to infect guinea pigs with fowl cholera but they didn’t get sick. Ok, so there is some host specificity, a deathly pathogen of the chicken may not kill a guinea pig.


Then someone got a little lazy or maybe they were just like had too much going on one day. But somebody let a culture of the fowl cholera pathogen sit for a few days before trying to infect the chickens. To everyone’s surprise, despite being injected with the pathogens the chickens did not get sick. So they decided to inject the same chickens with a fresh culture so they could continue their research. But what’s this? The chickens were still alive, were these super chickens?


Well sort of, because they were first inoculated with an old culture, a weak culture, the chicken's immune system was able to recognize that that microbe was like a bad microbe and they didn’t want that microbe floating around the chicken, so the immune system killed that microbe. But the immune system also did something else. It took a little picture of that microbe and hung it up on their most wanted list, like our most wanted list but just for the chicken. So when the microbe was injected once more, the chicken’s immune system launched a full-fledged attack and once more eliminated the microbial threat. This was the beginning of vaccines.


But, Louis Pasteur had more experiments to run. In February 1881 he started working on an anthrax vaccine. By May 5, 1881, he was ready for a public demonstration. He gathered 60 sheep, 25 of which received two doses of the vaccine before being given a lethal dose of Anthracis bacillus. The next 25 received only the lethal dose of Anthracis bacillus and the ten remaining sheep received no injection. One by one the group that had no vaccine died, but those that did receive the vaccine, were still standing day after day and week after week. At last, there was hope in the fight against Anthrax!


Cartoon drawing of Professor Xi's class where Psydney is giving a presentation on Louis Pasteur's experiment on vaccine development


Then, it seems Louis just became a one-trick giant, but the trick was a pretty good one I gotta say. He moved on and did a very similar thing with rabies. But rabies is a little bit different, it is caused by an RNA virus called lyssavirus. And he was really more of a bacteriologist or like a mycologist, I guess because of his yeast work. He didn’t really know how spectacular viruses were! He didn’t know how he could grow it in the lab without sacrificing a host. So he took an affected bunny, dried out its medulla (a piece of the brain), and injected it into some dogs. The dogs were in an area with other rabid animals, so they would get bit. But because of the protection, they received from the bunny brain, the dogs lived! Man, I just realized Louis Pasteur really killed a lot of things….I guess that is just part of science? Anyways.


Louis Pasteur was killing rabbits to save dogs and killing chickens to save sheep but could he save a giant? They aren’t really into killing one of their own for science, so this was another barrier to his research. But on July 6th, 1885 Louis Pasteur was presented with a kind of morbid gift. He was confronted by a sobbing mother, pulling her little second-generation behind her, begging Pasteur to be the savior of science that he is. This little giant was Joseph Meister, a 9-year old who just got infected with rabies.


I don’t know what Pasteur was thinking at this point, he must have been conflicted. His vaccine had gone through no trials, it did not receive approval from the scientific community to be tried on giants, there was no evidence showing his vaccine was not toxic for giants. To try it now, on this little giant, would not only be ignoring the scientific methods on which he has based his life, but it could also ruin him and destroy his reputation as a great scientist. On the other hand, no one has ever survived rabies, contracting it was a death sentence. To do nothing would be condemning the young one to death, stripping the hope from his mother and forcing her to watch as her son died, a terrible event that Louis Pasteur knew himself as he had already watched his daughters die at similar ages. He decided to air on the side of hope, injected the boy with his vaccine, and nervously waited on updates. The boy lived! Once more Pasteur proved his prowess over pathogens, his microbial mastery, and scientific superiority!


Thank you for that wonderful tale Psydney! What a fantastic way to end the class. Alright, that’s all for today! We’ll see you all next week to talk about Louis Pasteur’s rival, Robert Koch!

The majority of this blog was created due to the excellent book by Harvey Warren on Louis Pasteur.

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