Editing Louis Pasteur

{{short description|French chemist, pharmacist and microbiologist (1822–1895)}}
{{redirect|Pasteur}}
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{{Use dmy dates|date=January 2023}}{{Use American English|date=February 2016}}

{{Infobox scientist
| name              = Louis Pasteur
| honorific_suffix  = {{post-nominals|country=GBR|size=small|FRS}}
| image             = Louis Pasteur, foto av Paul Nadar, Crisco edit.jpg
| caption           = Photograph by [[Nadar]], 1895
| birth_date        = {{birth date|1822|12|27|df=y}}
| birth_place       = [[Dole, Jura|Dole]], France
| death_date        = {{death date and age|1895|9|28|1822|12|27|df=y}}
| death_place       = [[Marnes-la-Coquette]], France
| spouse            = {{marriage|[[Marie Laurent]]|1849}}
| children          = 5
| education         = {{ublist|[[École normale supérieure]]|[[University of Paris]]|[[Conservatoire national des arts et métiers]]}}
| fields            = {{Plainlist|
* [[Biology]]
* [[Microbiology]]
* [[Chemistry]]
* [[Mathematics]]
* [[Physics]]}}
| workplaces        = {{Plainlist|
* [[University of Strasbourg]]
* [[University of Lille]]
* [[École normale supérieure (Paris)|École Normale Supérieure]]
* [[Pasteur Institute]]}}
| notable_students  = [[Charles Friedel]]<ref>Asimov, ''[[Asimov's Biographical Encyclopedia of Science and Technology]]'' 2nd Revised edition</ref>
| known_for         = [[Anthrax vaccine]]<br>[[Cholera vaccine]]<br>[[Rabies vaccine]]<br>[[Chirality]]<br>[[Dextran]]<br>[[Fermentation theory]]<br>[[Galactose]]<br>[[Germ theory of disease]]<br>[[Kinetic resolution]]<br>[[Koch–Pasteur rivalry]]<br>[[Liebig–Pasteur dispute]]<br>[[Pasteurization]]<br>[[Pasteur effect]]<br>[[Eye dropper|Pasteur pipette]]<br>[[Chamberland filter|Pasteur–Chamberland filter]]<br>[[Racemic acid]]<br>[[Spontaneous generation]]<br>[[Swan neck flask]]<br>[[Stereochemistry]]<br>[[Zymology]]
| awards            = {{Plainlist|
* [[Legion of Honour|Legion of Honor Grand Cross]] (1881)
* [[Rumford Medal]] (1856)
* [[Copley Medal]] (1874)
* [[Albert Medal (Royal Society of Arts)|Albert Medal]] (1882)
* [[Cameron Prize for Therapeutics of the University of Edinburgh]] (1889)
* [[Leeuwenhoek Medal]] (1895)
* [[Order of the Medjidie]]<ref>{{cite web|title=II. Abdülhamid'in Fransız kimyagere yaptığı yardım ortaya çıktı|url=http://www.cnnturk.com/turkiye/ii-abdulhamidin-fransiz-kimyagere-yaptigi-yardim-ortaya-cikti?page=1|publisher=CNN Türk|access-date=29 December 2016|archive-date=26 December 2018|archive-url=https://web.archive.org/web/20181226034326/https://www.cnnturk.com/turkiye/ii-abdulhamidin-fransiz-kimyagere-yaptigi-yardim-ortaya-cikti?page=1|url-status=live}}</ref>}}
| signature         = Louis Pasteur Signature.svg
}}

'''Louis Pasteur''' {{post-nominals|country=GBR|size=small|ForMemRS}} ({{IPAc-en|ˈ|l|uː|i|_|p|æ|ˈ|s|t|ɜr}}, {{IPA|fr|lwi pastœʁ|lang|Fr-Louis Pasteur.wav}}; 27 December 1822 – 28 September 1895) was a French [[chemist]], [[pharmacist]], and [[microbiologist]] renowned for his discoveries of the principles of [[vaccination]], [[Fermentation|microbial fermentation]], and [[pasteurization]], the last of which was named after him. His research in chemistry led to remarkable breakthroughs in the understanding of the causes and preventions of [[diseases]], which laid down the foundations of hygiene, public health and much of modern medicine.<ref name="Ligon">{{cite journal|last1=Ligon|first1=B. Lee|year=2002|title=Biography: Louis Pasteur: A controversial figure in a debate on scientific ethics|journal=Seminars in Pediatric Infectious Diseases|volume=13|issue=2|pages=134–141|doi=10.1053/spid.2002.125138|pmid=12122952}}</ref> Pasteur's works are credited with saving millions of lives through the developments of vaccines for [[rabies vaccine|rabies]] and [[anthrax vaccine|anthrax]]. He is regarded as one of the founders of modern [[bacteriology]] and has been honored as the "father of bacteriology"<ref>{{Cite journal|last=Adam|first=P.|year=1951|title=Louis Pasteur: Father of bacteriology|url=https://pubmed.ncbi.nlm.nih.gov/14870064|journal=Canadian Journal of Medical Technology|volume=13|issue=3|pages=126–128|pmid=14870064|access-date=29 April 2021|archive-date=30 April 2021|archive-url=https://web.archive.org/web/20210430193010/https://pubmed.ncbi.nlm.nih.gov/14870064/|url-status=live}}</ref> and the "father of [[microbiology]]"<ref name="fein">{{cite book|author= Feinstein, S|title= Louis Pasteur: The Father of Microbiology |url=https://books.google.com/books?id=0mwwzIdiuhkC|year= 2008|pages= 1–128|publisher= Enslow Publishers, Inc.|isbn =978-1-59845-078-1}}</ref><ref>{{Cite journal|last=Fleming|first=Alexander|year=1952|title=Freelance of Science|journal=British Medical Journal|volume=2|issue=4778|pages=269|doi=10.1136/bmj.2.4778.269|pmc=2020971}}</ref> (together with [[Robert Koch]];<ref>{{Cite journal|last1=Tan|first1=S. Y.|last2=Berman|first2=E.|year=2008|title=Robert Koch (1843–1910): father of microbiology and Nobel laureate|url=https://pubmed.ncbi.nlm.nih.gov/19037548|journal=Singapore Medical Journal|volume=49|issue=11|pages=854–855|pmid=19037548|access-date=29 April 2021|archive-date=22 April 2021|archive-url=https://web.archive.org/web/20210422125336/https://pubmed.ncbi.nlm.nih.gov/19037548/|url-status=live}}</ref><ref name=":9">{{Cite journal|last=Gradmann|first=Christoph|year=2006|title=Robert Koch and the white death: from tuberculosis to tuberculin|journal=Microbes and Infection|volume=8|issue=1|pages=294–301|doi=10.1016/j.micinf.2005.06.004|pmid=16126424|doi-access=free}}</ref> the latter epithet also attributed to [[Antonie van Leeuwenhoek]]).<ref>{{Cite journal|last=Lane|first=Nick|year=2015|title=The unseen world: reflections on Leeuwenhoek (1677) 'Concerning little animals'|journal=Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences|volume=370|issue=1666|pages=20140344|doi=10.1098/rstb.2014.0344|pmc=4360124|pmid=25750239}}</ref>

Pasteur was responsible for disproving the doctrine of [[spontaneous generation]]. Under the auspices of the [[French Academy of Sciences]], his experiment demonstrated that in sterilized and sealed flasks, nothing ever developed; conversely, in sterilized but open flasks, microorganisms could grow.<ref name="seckbach">{{cite book|editor-last1=Seckbach |editor-first1=Joseph |title=Origins: Genesis, Evolution and Diversity of Life|year=2004|publisher=Kluwer Academic Publishers|location=Dordrecht, The Netherlands|isbn=978-1-4020-1813-8|page=20|url=https://books.google.com/books?id=937NljkEbgYC}}</ref> For this experiment, the academy awarded him the Alhumbert Prize carrying 2,500 [[francs]] in 1862.

Pasteur is also regarded as one of the fathers of the [[germ theory of diseases]], which was a minor medical concept at the time.<ref name="ullmann">{{Cite journal| last = Ullmann| first = Agnes| title = Pasteur-Koch: Distinctive Ways of Thinking about Infectious Diseases| journal = Microbe| volume = 2| issue = 8| pages = 383–387| date = August 2007| url = http://www.asm.org/index.php/component/content/article/114-unknown/unknown/4469-pasteur-koch-distinctive-ways-of-thinking-about-infectious-diseases| access-date = 12 December 2007| archive-url = https://web.archive.org/web/20160510103839/http://www.asm.org/index.php/component/content/article/114-unknown/unknown/4469-pasteur-koch-distinctive-ways-of-thinking-about-infectious-diseases| archive-date = 10 May 2016| url-status = dead}}</ref> 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. Pasteur also made significant [[#Molecular asymmetry|discoveries]] in chemistry, most notably on the molecular basis for the [[asymmetry]] of certain [[crystals]] and [[racemization]]. Early in his career, his investigation of [[sodium ammonium tartrate]] initiated the field of [[Chirality (chemistry)|optical isomerism]]. This work had a profound effect on structural chemistry, with eventual implications for many areas including [[medicinal chemistry]].

He was the director of the [[Pasteur Institute]], established in 1887, until his death, and his body was interred in a vault beneath the institute. Although Pasteur made groundbreaking experiments, his reputation became associated with various controversies. Historical reassessment of his notebook revealed that he practiced deception to overcome his rivals.<ref name=Geison1995>{{cite book|last1=Geison|first1=Gerald L|title=The Private Science of Louis Pasteur|year=1995|publisher=Princeton University Press|location=Princeton, NJ|isbn=978-0-691-01552-1|url=http://press.princeton.edu/titles/5670.html|access-date=26 October 2014|archive-date=26 October 2014|archive-url=https://web.archive.org/web/20141026131627/http://press.princeton.edu/titles/5670.html|url-status=live}}</ref><ref>{{Cite journal |last=Anderson |first=Christopher |date=1993-02-19 |title=Pasteur Notebooks Reveal Deception |url=https://www.science.org/doi/10.1126/science.259.5098.1117.b |journal=Science |language=en |volume=259 |issue=5098 |pages=1117 |doi=10.1126/science.259.5098.1117.b |pmid=8438162 |issn=0036-8075}}</ref>

== Early life and education ==
{{multiple image
| total_width  = 285
| align        = left
| direction    = horizontal
| image1       = Françoise Foliot - Musée Pasteur - Portrait de Jean-Joseph Pasteur.jpg
| image2       = Françoise Foliot - Musée Pasteur - Portrait de Jeanne-Étiennette Roqui.jpg
| footer       = Portraits of Pasteur's parents, painted by himself
| footer_align = left
}}
[[File:Louis Pasteur Geburtshaus in Dole.jpg|thumb|upright|right|The house in which Pasteur was born, [[Dole, Jura|Dole]]]]
Louis Pasteur was born on 27 December 1822, in [[Dole, Jura]], France, to a [[Catholic]] family of a poor [[tanner (occupation)|tanner]].<ref name="catholic intro">{{CathEncy|wstitle=Louis Pasteur|author=James J. Walsh}}</ref> He was the third child of Jean-Joseph Pasteur and Jeanne-Etiennette Roqui. The family moved to [[Marnoz]] in 1826 and then to [[Arbois]] in 1827.<ref>{{cite book|last1=Debré|first1=Patrice|translator-last=Forster|translator-first=Elborg|title=Louis Pasteur|date=2000|publisher=JHU Press|location=Baltimore|isbn=978-0-8018-6529-9|pages=6–7|url=https://books.google.com/books?id=RzOcl-FLw30C&pg=PA6}}</ref><ref>{{cite book|last1=Robbins|first1=Louise|title=Louis Pasteur and the Hidden World of Microbes|date=2001|publisher=Oxford University Press|location=New York|isbn=978-0-19-512227-5|page=14|url=https://books.google.com/books?id=qUHuafXKKBEC&pg=PA14}}</ref> Pasteur entered primary school in 1831.<ref>{{cite book|last1=Debré|first1=Patrice|translator-last=Forster|translator-first=Elborg|title=Louis Pasteur|date=2000|publisher=JHU Press|location=Baltimore|isbn=978-0-8018-6529-9|pages=8|url=https://books.google.com/books?id=RzOcl-FLw30C&pg=PA8}}</ref> He was [[dyslexic]] and [[dysgraphic]].<ref>{{cite book|title=101 Things You Didn't Know about Einstein: Sex, Science, and the Secrets of the Universe|last1=Phillips|first1=Cynthia|last2=Priwer|first2=Shana|publisher= Adams Media |date=2018|page=21}}</ref><ref>{{cite web|title=Famous People with Learning Disabilities|url=https://www.gemmlearning.com/blog/learning-issues/famous-people-with-learning-disabilities/|last=Geffner|first=Donna|website=Gemm Learning|date=2013|access-date=3 January 2023|archive-date=3 January 2023|archive-url=https://web.archive.org/web/20230103104015/https://www.gemmlearning.com/blog/learning-issues/famous-people-with-learning-disabilities/|url-status=live}}</ref><ref>{{cite book|isbn=978-1909421264|title=A Short History of Human Error|last1=Thomson|first1=Oliver|publisher= Arena Books Ltd  |date=2013|page=92}}</ref>

He was an average student in his early years, and not particularly academic, as his interests were [[fishing]] and [[sketch (drawing)|sketching]].<ref name="catholic intro" /> He drew many pastels and portraits of his parents, friends and neighbors.<ref>{{cite book|last1=Debré|first1=Patrice|translator-last=Forster|translator-first=Elborg|title=Louis Pasteur|date=2000|publisher=JHU Press|location=Baltimore|isbn=978-0-8018-6529-9|pages=12–13|url=https://books.google.com/books?id=RzOcl-FLw30C&pg=PA12}}</ref> Pasteur attended secondary school at the Collège d'Arbois.<ref>{{cite book|last1=Robbins|first1=Louise|title=Louis Pasteur and the Hidden World of Microbes|date=2001|publisher=Oxford University Press|location=New York|isbn=978-0-19-512227-5|page=15|url=https://books.google.com/books?id=qUHuafXKKBEC&pg=PA15}}</ref> In October 1838, he left for Paris to enroll in a [[boarding school]], but became [[Homesickness|homesick]] and returned in November.<ref>{{cite book|last1=Debré|first1=Patrice|translator-last=Forster|translator-first=Elborg|title=Louis Pasteur|date=2000|publisher=JHU Press|location=Baltimore|isbn=978-0-8018-6529-9|pages=11–12|url=https://books.google.com/books?id=RzOcl-FLw30C&pg=PA11}}</ref>

In 1839, he entered the {{ill|Secondary education in France|fr|Collège Victor-Hugo|lt=Collège Royal|display=1}} at [[Besançon]] to study philosophy and earned his Bachelor of Letters degree in 1840.<ref>{{cite book|last1=Keim|first1=Albert|last2=Lumet|first2=Louis|title=Louis Pasteur|date=1914|publisher=Frederick A. Stokes Company|pages=10, 12|url=https://archive.org/stream/louispasteur00keim#page/10/mode/2up}}</ref> He was appointed a tutor at the Besançon college while continuing a degree science course with special mathematics.<ref>{{cite book|last1=Debré|first1=Patrice|translator-last=Forster|translator-first=Elborg|title=Louis Pasteur|date=2000|publisher=JHU Press|location=Baltimore|isbn=978-0-8018-6529-9|pages=14, 17|url=https://books.google.com/books?id=RzOcl-FLw30C&pg=PA14}}</ref> He failed his first examination in 1841. He managed to pass the ''[[Baccalauréat|baccalauréat scientifique]]'' (general science) degree from [[Dijon]], where he earned his Bachelor of Science in Mathematics degree (Bachelier ès Sciences Mathématiques) in 1842,<ref name="Math">{{Cite web|url=https://www.ens.psl.eu/portraits-de-normaliens/louis-pasteur-1822-1895|title=Louis Pasteur (1822–1895) &#124; ENS|website=www.ens.psl.eu|access-date=30 October 2021|archive-date=30 October 2021|archive-url=https://web.archive.org/web/20211030231957/https://www.ens.psl.eu/portraits-de-normaliens/louis-pasteur-1822-1895|url-status=live}}</ref> but with a mediocre grade in chemistry.<ref>{{cite book|last1=Debré|first1=Patrice|translator-last=Forster|translator-first=Elborg|title=Louis Pasteur|date=2000|publisher=JHU Press|location=Baltimore|isbn=978-0-8018-6529-9|pages=19–20|url=https://books.google.com/books?id=RzOcl-FLw30C&pg=PA19}}</ref>

Later in 1842, Pasteur took the entrance test for the [[École normale supérieure (Paris)|École Normale Supérieure]].<ref>{{cite book|last1=Robbins|first1=Louise|title=Louis Pasteur and the Hidden World of Microbes|date=2001|publisher=Oxford University Press|location=New York|isbn=978-0-19-512227-5|page=18|url=https://books.google.com/books?id=qUHuafXKKBEC&pg=PA18}}</ref> During the test, he had to fight fatigue and only felt comfortable with physics and mathematics.<ref>{{Cite book |last=Debré |first=Patrice |url= |title=Louis Pasteur |date=2000-11-27 |publisher=JHU Press |isbn=978-0-8018-6529-9 |pages=21 |language=en}}</ref> He passed the first set of tests, but because his ranking was low, Pasteur decided not to continue and try again next year.<ref>{{cite book|last1=Debré|first1=Patrice|translator-last=Forster|translator-first=Elborg|title=Louis Pasteur|date=2000|publisher=JHU Press|location=Baltimore|isbn=978-0-8018-6529-9|pages=20–21|url=https://books.google.com/books?id=RzOcl-FLw30C&pg=PA20}}</ref> He went back to the Parisian boarding school to prepare for the test. He also attended classes at the [[Lycée Saint-Louis]] and lectures of [[Jean-Baptiste Dumas]] at the [[University of Paris|Sorbonne]].<ref>{{cite book|last1=Keim|first1=Albert|last2=Lumet|first2=Louis|title=Louis Pasteur|date=1914|publisher=Frederick A. Stokes Company|pages=15–17|url=https://archive.org/stream/louispasteur00keim#page/14/mode/2up}}</ref> In 1843, he passed the test with a high ranking and entered the [[École normale supérieure (Paris)|École Normale Supérieure]].<ref>{{cite book|last1=Debré|first1=Patrice|translator-last=Forster|translator-first=Elborg|title=Louis Pasteur|date=2000|publisher=JHU Press|location=Baltimore|isbn=978-0-8018-6529-9|pages=23–24|url=https://books.google.com/books?id=RzOcl-FLw30C&pg=PA24}}</ref> Later, he is a student of [[Jean-Baptiste Boussingault]] at the [[Conservatoire national des arts et métiers]].<ref>{{cite book|last1=Legros|first1=Jean-Paul|translator-last=|translator-first=|title=D'Olivier de Serres à René Dumont : portraits d'agronomes|date=1998|publisher=Technique et documentation|location=Paris|isbn=2-7430-0289-1|pages=|url=}}</ref> In 1845 he received the {{ill|Licence de biologie|fr|Licence de biologie|lt=licencié ès sciences|italic=yes}} degree.<ref name="Debré and Forster p. 502">{{cite book|last1=Debré|first1=Patrice|translator-last=Forster|translator-first=Elborg|title=Louis Pasteur|date=2000|publisher=JHU Press|location=Baltimore|isbn=978-0-8018-6529-9|pages=502}}</ref> In 1846, he was appointed professor of physics at the {{ill|Secondary education in France|fr|Lycée Gabriel-Faure|lt=Collège de Tournon|display=1}} in [[Ardèche]]. But the chemist [[Antoine Jérôme Balard]] wanted him back at the ''École Normale Supérieure'' as a graduate laboratory assistant (''agrégé préparateur'').<ref>{{cite book|last1=Debré|first1=Patrice|translator-last=Forster|translator-first=Elborg|title=Louis Pasteur|date=2000|publisher=JHU Press|location=Baltimore|isbn=978-0-8018-6529-9|pages=29–30|url=https://books.google.com/books?id=RzOcl-FLw30C&pg=PA29}}</ref> He joined Balard and simultaneously started his research in [[crystallography]] and in 1847, he submitted his two theses, one in chemistry and the other in physics: (a) Chemistry Thesis: "Recherches sur la capacité de saturation de l'acide arsénieux. Etudes des arsénites de potasse, de soude et d'ammoniaque."; (b) Physics Thesis: "1. Études des phénomènes relatifs à la polarisation rotatoire des liquides. 2. Application de la polarisation rotatoire des liquides à la solution de diverses questions de chimie."<ref name="Thesis">{{cite book|title=Louis Pasteur, Thèse de Chimie, Thèse de Physique|year=1847|url=https://gallica.bnf.fr/ark:/12148/bpt6k141151t/f29.image/|access-date=31 October 2021|archive-date=31 October 2021|archive-url=https://web.archive.org/web/20211031013640/https://gallica.bnf.fr/ark:/12148/bpt6k141151t/f29.image/|url-status=live}}</ref><ref name="Debré and Forster p. 502" /><ref>{{cite book|last1=Keim|first1=Albert|last2=Lumet|first2=Louis|title=Louis Pasteur|date=1914|publisher=Frederick A. Stokes Company|pages=28–29|url=https://archive.org/stream/louispasteur00keim#page/28/mode/2up}}</ref>

After serving briefly as professor of physics at the Dijon [[Lycée]] in 1848, he became professor of chemistry at the [[University of Strasbourg]],<ref>{{cite book|last1=Keim|first1=Albert|last2=Lumet|first2=Louis|title=Louis Pasteur|date=1914|publisher=Frederick A. Stokes Company|pages=37–38|url=https://archive.org/stream/louispasteur00keim#page/36/mode/2up}}</ref> where he met and courted [[Marie Laurent]], daughter of the university's [[Rector (academia)|rector]] in 1849. They were married on 29 May 1849,<ref>{{cite book|last1=Holmes|first1=Samuel J.|title=Louis Pasteur|date=1924|publisher=Harcourt, Brace and company|pages=34–36|url=https://archive.org/stream/louispasteur00holm#page/34/mode/2up}}</ref> and together had five children, only two of whom survived to adulthood;<ref>{{cite book|last1=Robbins|first1=Louise E.|title=Louis Pasteur and the Hidden World of Microbes|date=2001|publisher=Oxford University Press|isbn=978-0-19-028404-6|page=56|url=https://books.google.com/books?id=NdLhBwAAQBAJ&pg=PA56}}</ref> the other three died of [[typhoid]].

== Career ==
[[File:Louis Pasteur, French biologist, 1878, Paris slnsw.jpg|thumb|Louis Pasteur, French biologist and chemist, 1878, by A Gerschel]]
Pasteur was appointed professor of chemistry at the University of Strasbourg in 1848, and became the chair of chemistry in 1852.<ref>{{cite book|last1=Debré|first1=Patrice|translator-last=Forster|translator-first=Elborg|title=Louis Pasteur|date=2000|publisher=JHU Press|location=Baltimore|isbn=978-0-8018-6529-9|pages=502–503}}</ref>

In February 1854, so that he would have time to carry out work that could earn him the title of correspondent of the Institute, he got three months' paid leave with the help of a medical certificate of convenience.<ref>"Without this work that I was asked to do for the Correspondence of the Institute, I would have stayed in Strasbourg. But you understand that this leave that these missions made me have with full salary is an irregularity that needs to be covered by a health reason." (Pasteur, letter of 25 February 1854 to his father, in Pasteur, ''Correspondence'', t. 1, Paris, 1940, p. 261.)</ref> He extended the leave until 1 August, the date of the start of the exams. "I tell the Minister that I will go and do the examinations so as not to increase the embarrassment of the service. It is also so as not to leave to another a sum of 6 or 700 francs".<ref>Pasteur, letter of 8 May 1854 to his father, in Pasteur, ''Correspondence'', t. 1, Paris, 1940, p. 267. This episode in Pasteur's career is noted by Pierre-Yves Laurioz, ''Louis Pasteur. La réalité après la légende'', Paris, 2003, pp. 79–81. On Pasteur's attitude towards money, see Richard Moreau, ''La Préhistoire de Pasteur'', Paris, L'Harmattan, 2000, pp. 257–262.</ref>

In this same year 1854, he was named dean of the new faculty of sciences at [[University of Lille]], where he began his studies on fermentation.<ref name=Chirality /> It was on this occasion that Pasteur uttered his oft-quoted remark: "''dans les champs de l'observation, le hasard ne favorise que les esprits préparés''" ("In the field of observation, chance favors only the prepared mind").<ref>L. Pasteur, ''"Discours prononcé à Douai, le 7 décembre 1854, à l'occasion de l'installation solennelle de la Faculté des lettres de Douai et de la Faculté des sciences de Lille"'' (Speech delivered at Douai on 7 December 1854 on the occasion of his formal inauguration to the Faculty of Letters of Douai and the Faculty of Sciences of Lille), reprinted in: Pasteur Vallery-Radot, ed., ''Oeuvres de Pasteur'' (Paris, France: Masson and Co., 1939), vol. 7, [http://gallica.bnf.fr/ark:/12148/bpt6k7363q/f137.chemindefer p. 131] {{Webarchive|url=https://web.archive.org/web/20120109090835/http://gallica.bnf.fr/ark:/12148/bpt6k7363q/f137.chemindefer |date=9 January 2012 }}.</ref>

In 1857, he moved to Paris as the director of scientific studies at the ''[[École Normale Supérieure]]'' where he took control from 1858 to 1867 and introduced a series of reforms to improve the standard of scientific work. The examinations became more rigid, which led to better results, greater competition, and increased prestige. Many of his decrees, however, were rigid and authoritarian, leading to two serious student revolts. During "the bean revolt" he decreed that a mutton stew, which students had refused to eat, would be served and eaten every Monday. On another occasion he threatened to expel any student caught smoking, and 73 of the 80 students in the school resigned.<ref name=Debre>{{cite book|last1=Debré|first1=Patrice|others= Translated by Elborg Forster|title=Louis Pasteur|year=2000|publisher=Johns Hopkins University Press|location=Baltimore|isbn=978-0-8018-6529-9|pages=119–120|url=https://books.google.com/books?id=RzOcl-FLw30C&pg=PA119|access-date=27 January 2015}}</ref>

In 1863, he was appointed professor of geology, physics, and chemistry at the ''[[École nationale supérieure des Beaux-Arts]]'', a position he held until his resignation in 1867. In 1867, he became the chair of organic chemistry at the Sorbonne,<ref name="Debré & Patrice pp. 505-7">{{cite book |last1=Debré |first1=Patrice |translator-last=Forster |translator-first=Elborg |title=Louis Pasteur|date=2000 |publisher=JHU Press |location=Baltimore |isbn=978-0-8018-6529-9 |pages=505–507}}</ref> but he later gave up the position because of poor health.<ref>{{cite book|last1=Vallery-Radot|first1=René|translator-last=Devonshire|translator-first=R. L.|title=The Life of Pasteur|date=1919|publisher=Constable & Company|location=London|page=246|url=https://archive.org/stream/in.ernet.dli.2015.173907/2015.173907.The-Life-Of-Pasteur#page/n265/mode/2up}}</ref> In 1867, the École Normale's laboratory of physiological chemistry was created at Pasteur's request,<ref name="Debré & Patrice pp. 505-7" /> and he was the laboratory's director from 1867 to 1888.<ref>{{cite encyclopedia |editor-last=Heilbron|editor-first=J. L.|title=Pasteur, Louis |encyclopedia=The Oxford Companion to the History of Modern Science |page=617|year=2003|publisher=Oxford University Press|isbn=978-0-19-974376-6 |url=https://books.google.com/books?id=abqjP-_KfzkC&pg=PA617}}</ref> In Paris, he established the Pasteur Institute in 1887, in which he was its director for the rest of his life.<ref name=fein /><ref name="van">{{cite book|last1=Hook|first1=Sue Vander|url=https://archive.org/details/louispasteurgrou0000vand|title=Louis Pasteur: Groundbreaking Chemist & Biologist|publisher=ABDO Publishing Company|year=2011|isbn=978-1-61758-941-6|location=Minnesota|pages=[https://archive.org/details/louispasteurgrou0000vand/page/8 8]–112|url-access=registration}}</ref>

== Research ==

=== Molecular asymmetry ===
[[File:Pcrystals.svg|thumb|Pasteur separated the left and right [[crystal]] shapes from each other to form two piles of crystals: in solution one form rotated light to the left, the other to the right, while an [[Racemic mixture|equal mixture]] of the two forms canceled each other's effect, and does not rotate the [[polarized light]].]]

In Pasteur's early work as a [[chemist]], beginning at the ''École Normale Supérieure'', and continuing at Strasbourg and Lille, he examined the chemical, optical and crystallographic properties of a group of compounds known as [[tartrates]].<ref name="Flack" />

He resolved a problem concerning the nature of [[tartaric acid]] in 1848.<ref>L. Pasteur (1848) [http://gallica.bnf.fr/ark:/12148/bpt6k2983p/f539.item.r=.zoom "Mémoire sur la relation qui peut exister entre la forme cristalline et la composition chimique, et sur la cause de la polarisation rotatoire"] {{Webarchive|url=https://web.archive.org/web/20161021035454/http://gallica.bnf.fr/ark:/12148/bpt6k2983p/f539.item.r=.zoom |date=21 October 2016 }} (Memoir on the relationship that can exist between crystalline form and chemical composition, and on the cause of rotary polarization)," ''Comptes rendus de l'Académie des sciences'' (Paris), '''26''': 535–538.</ref><ref>L. Pasteur (1848) [https://books.google.com/books?id=gJ45AAAAcAAJ&pg=PA442 "Sur les relations qui peuvent exister entre la forme cristalline, la composition chimique et le sens de la polarisation rotatoire"] (On the relations that can exist between crystalline form, and chemical composition, and the sense of rotary polarization), ''Annales de Chimie et de Physique'', 3rd series, vol. 24, no. 6, pp.&nbsp;442–459.</ref><ref>George B. Kauffman and Robin D. Myers (1998)[https://web.archive.org/web/20060117144722/http://192.129.24.144/licensed_materials/00897/papers/0003006/36kau897.pdf "Pasteur's resolution of racemic acid: A sesquicentennial retrospect and a new translation,"] ''The Chemical Educator'', vol. 3, no. 6, pp. 1–4, {{doi|10.1007/s00897980257a}}</ref><ref name=Gal>Joseph Gal: ''Louis Pasteur, Language, and Molecular Chirality. I. Background and Dissymmetry'', Chirality ''23'' ('''2011''') 1–16.</ref> A solution of this compound derived from living things [[Optical rotation|rotated]] the [[plane of polarization]] of light passing through it.<ref name="Flack">H.D. Flack (2009) [http://crystal.flack.ch/dox/sh5092.pdf "Louis Pasteur's discovery of molecular chirality and spontaneous resolution in 1848, together with a complete review of his crystallographic and chemical work,"] {{Webarchive|url=https://web.archive.org/web/20190908211420/http://crystal.flack.ch/dox/sh5092.pdf |date=8 September 2019 }} ''Acta Crystallographica'', Section A, vol. 65, pp.&nbsp;371–389.</ref> The problem was that tartaric acid derived by [[chemical synthesis]] had no such effect, even though its chemical reactions were identical and its elemental composition was the same.<ref name="cohn" />

Pasteur noticed that crystals of tartrates had small faces. Then he observed that, in [[racemic mixture]]s of tartrates, half of the crystals were right-handed and half were left-handed. In solution, the right-handed compound was [[dextrorotatory]], and the left-handed one was levorotatory.<ref name="Flack" /> Pasteur determined that optical activity related to the shape of the crystals, and that an asymmetric internal arrangement of the molecules of the compound was responsible for twisting the light.<ref name=Chirality>{{cite web|title=Louis Pasteur|url=https://www.sciencehistory.org/historical-profile/louis-pasteur|website=[[Science History Institute]]|access-date=20 March 2018|date=June 2016|archive-date=21 March 2018|archive-url=https://web.archive.org/web/20180321132243/https://www.sciencehistory.org/historical-profile/louis-pasteur|url-status=live}}</ref> The (2''R'',3''R'')- and (2''S'',3''S'')- tartrates were isometric, non-superposable mirror images of each other. This was the first time anyone had demonstrated [[Chirality (chemistry)|molecular chirality]], and also the first explanation of [[isomer]]ism.<ref name="Flack" />

Some historians consider Pasteur's work in this area to be his "most profound and most original contributions to science", and his "greatest scientific discovery."<ref name="Flack" />

=== Fermentation and germ theory of diseases ===

Pasteur was motivated to investigate fermentation while working at Lille. In 1856 a local wine manufacturer, M. Bigot, whose son was one of Pasteur's students, sought for his advice on the problems of making beetroot alcohol and souring.<ref>{{cite book|last1=Vallery-Radot|first1=René|translator-last=Devonshire|translator-first=R. L.|title=The Life of Pasteur|date=1919|publisher=Constable & Company|location=London|page=79|url=https://archive.org/stream/in.ernet.dli.2015.173907/2015.173907.The-Life-Of-Pasteur#page/n101/mode/2up}}</ref><ref name=Ligon /> Pasteur began his research in the topic by repeating and confirming works of [[Theodor Schwann]], who demonstrated a decade earlier that yeast were alive.

According to his son-in-law, René Vallery-Radot, in August 1857 Pasteur sent a paper about lactic acid fermentation to the Société des Sciences de Lille, but the paper was read three months later.<ref>{{cite book|last1=Vallery-Radot|first1=René|title=La vie de Pasteur|date=1907|publisher=Librairie Hachette|location=Paris|page=98|url=https://archive.org/stream/laviedepasteur01vallgoog#page/n110/mode/2up|language=fr}}</ref> A memoire was subsequently published on 30 November 1857.<ref>{{cite journal|last1=Pasteur|first1=Louis|title=Mémoire sur la fermentation appelée lactique|journal=Comptes Rendus Chimie|year=1857|volume=45|pages=913–916|url=http://gallica.bnf.fr/ark:/12148/bpt6k30026.image.r=+COMPTES+RENDUS+++DES+S%C3%89ANCES+DE+L.f915.langFR|language=fr|access-date=11 March 2017|archive-date=12 March 2017|archive-url=https://web.archive.org/web/20170312141626/http://gallica.bnf.fr/ark:/12148/bpt6k30026.image.r=+COMPTES+RENDUS+++DES+S%C3%89ANCES+DE+L.f915.langFR|url-status=live}}</ref> In the memoir, he developed his ideas stating that: "I intend to establish that, just as there is an alcoholic ferment, the yeast of beer, which is found everywhere that sugar is decomposed into alcohol and carbonic acid, so also there is a particular ferment, a [[lactic acid bacteria|lactic yeast]], always present when [[Lactic acid fermentation|sugar becomes lactic acid]]."<ref name=manchester2007>{{cite journal|last1=Manchester|first1=K.L.|title=Louis Pasteur, fermentation, and a rival|journal=South African Journal of Science|year=2007|volume=103|issue=9–10|pages=377–380|url=http://www.scielo.org.za/scielo.php?pid=S0038-23532007000500008&script=sci_arttext|access-date=26 October 2014|archive-date=26 October 2014|archive-url=https://web.archive.org/web/20141026053500/http://www.scielo.org.za/scielo.php?pid=S0038-23532007000500008&script=sci_arttext|url-status=live}}</ref>

This memoir on alcoholic fermentation was published in full form in 1858.<ref>{{cite journal|last1=Pasteur|first1=Louis|title=Nouveaux faits concernant l'histoire de la fermentation alcoolique|journal=Comptes Rendus Chimie|year=1858|volume=47|pages=1011–1013|language=fr}}</ref><ref>{{cite journal|last1=Pasteur|first1=Louis|title=Nouveaux faits concernant l'histoire de la fermentation alcoolique|journal=Annales de Chimie et de Physique |series=3rd Series|year=1858|volume=52|pages=404–418|language=fr}}</ref> [[Jöns Jacob Berzelius]] and [[Justus von Liebig]] had proposed the theory that fermentation was caused by decomposition. Pasteur demonstrated that this theory was incorrect, and that yeast was responsible for fermentation to produce alcohol from sugar.<ref name=Barnett>{{cite book|last1=Barnett|first1=James A.|last2=Barnett|first2=Linda|title=Yeast Research: A Historical Overview|year=2011|publisher=ASM Press|location=Washington, DC|isbn=978-1-55581-516-5|url=https://books.google.com/books?id=ZwisBAAAQBAJ}}</ref> He also demonstrated that, when a different microorganism contaminated the wine, lactic acid was produced, making the wine sour.<ref name=Ligon /> In 1861, Pasteur observed that less sugar fermented per part of yeast when the yeast was exposed to air.<ref name=Barnett /> The lower rate of fermentation aerobically became known as the [[Pasteur effect]].<ref>{{cite book|editor1-last=Zimmermann|editor1-first=F.K.|editor2-last=Entian|editor2-first=K.-D.|title=Yeast Sugar Metabolism|date=1997|publisher=CRC Press|isbn=978-1-56676-466-7|pages=20–21|url=https://books.google.com/books?id=VSQZ1AVg74oC&pg=PA20}}</ref>
[[File:Louis Pasteur experiment.jpg|thumb|left|Pasteur experimenting in his laboratory]]
[[File:LouisPasteurMonumentLille.jpg|thumb|[[Institut Pasteur de Lille]]]]

Pasteur's research also showed that the growth of micro-organisms was responsible for spoiling beverages, such as beer, wine and milk. With this established, he invented a process in which liquids such as milk were heated to a temperature between 60 and 100&nbsp;°C.<ref name=Bowden /> This killed most bacteria and moulds already present within them. Pasteur and [[Claude Bernard]] completed tests on blood and urine on 20 April 1862.<ref>{{cite book|last1=Vallery-Radot|first1=René|translator-last=Devonshire|translator-first=R.L.|title=The Life of Pasteur|date=1919|publisher=Constable & Company|location=London|page=104|url=https://archive.org/stream/in.ernet.dli.2015.173907/2015.173907.The-Life-Of-Pasteur#page/n125/mode/2up}}</ref> Pasteur patented the process, to fight the "diseases" of wine, in 1865.<ref name=Bowden>{{cite book|last1=Bowden|first1=Mary Ellen|last2=Crow|first2=Amy Beth|last3=Sullivan|first3=Tracy|title=Pharmaceutical achievers: the human face of pharmaceutical research|year=2003|publisher=Chemical Heritage Press|location=Philadelphia|isbn=978-0-941901-30-7|url=https://books.google.com/books?id=4yPPE0xHEmkC&pg=PA6}}</ref> The method became known as [[pasteurization]], and was soon applied to beer and milk.<ref name=Nelson2009>{{cite journal|last1=Nelson|first1=Bryn|title=The Lingering Heat over Pasteurized Milk|journal=Chemical Heritage Magazine|year=2009|volume=27|issue=1|url=https://www.sciencehistory.org/distillations/article/lingering-heat-over-pasteurized-milk|access-date=20 March 2018|archive-date=21 March 2018|archive-url=https://web.archive.org/web/20180321192530/https://www.sciencehistory.org/distillations/article/lingering-heat-over-pasteurized-milk|url-status=live}}</ref>

Beverage contamination led Pasteur to the idea that micro-organisms infecting animals and humans cause disease. He proposed preventing the entry of micro-organisms into the human body, leading [[Joseph Lister]] to develop [[antiseptic]] methods in surgery.<ref name=Listerine>{{cite journal|last1=Hicks|first1=Jesse|title=A Fresh Breath|url=http://www.chemheritage.org/discover/online-resources/thanks-to-chemistry/listerine.aspx|journal=Chemical Heritage Magazine |access-date=27 January 2015 |url-status=dead |archive-url=https://web.archive.org/web/20160611130657/http://www.chemheritage.org/discover/online-resources/thanks-to-chemistry/listerine.aspx|archive-date=11 June 2016}}</ref>

In 1866, Pasteur published ''Études sur le Vin'', about the diseases of wine, and he published ''Études sur la Bière'' in 1876, concerning the diseases of beer.<ref name=Barnett />

In the early 19th century, [[Agostino Bassi]] had shown that [[muscardine]] was caused by a fungus that infected silkworms.<ref name=Hatcher /> Since 1853, two diseases called ''[[pébrine]]'' and ''[[flacherie]]'' had been infecting great numbers of [[silkworm]]s in southern France, and by 1865 they were causing huge losses to farmers. In 1865, Pasteur went to [[Alès]] and worked for five years until 1870.<ref name=Berche>{{cite journal|last1=Berche|first1=P.|title=Louis Pasteur, from crystals of life to vaccination|journal=Clinical Microbiology and Infection|year=2012|volume=18|issue=s5|pages=1–6|doi=10.1111/j.1469-0691.2012.03945.x|pmid=22882766|doi-access=free}}</ref><ref name="Schwartz">{{cite journal|last1=Schwartz|first1=M.|year=2001|title=The life and works of Louis Pasteur|journal=Journal of Applied Microbiology|volume=91|issue=4|pages=597–601|doi=10.1046/j.1365-2672.2001.01495.x|pmid=11576293|doi-access=|s2cid=39020116}}</ref>

Silkworms with pébrine were covered in corpuscles. In the first three years, Pasteur thought that the corpuscles were a symptom of the disease. In 1870, he concluded that the corpuscles were the cause of pébrine (it is now known that the cause is a [[microsporidian]]).<ref name=Hatcher>{{cite book|last1=Hatcher|first1=Paul|last2=Battey|first2=Nick|title=Biological Diversity: Exploiters and Exploited|date=2011|publisher=John Wiley & Sons|isbn=978-0-470-97986-0|pages=88–89, 91|url=https://books.google.com/books?id=FpQpedSpeWMC&pg=PA89}}</ref> Pasteur also showed that the disease was hereditary.<ref name="Keim pp. 87-88">{{cite book|last1=Keim|first1=Albert|last2=Lumet|first2=Louis|title=Louis Pasteur|date=1914|publisher=Frederick A. Stokes Company|pages=87–88|url=https://archive.org/stream/louispasteur00keim#page/86/mode/2up}}</ref> Pasteur developed a system to prevent pébrine: after the female moths laid their eggs, the moths were turned into a pulp. The pulp was examined with a microscope, and if corpuscles were observed, the eggs were destroyed.<ref>{{cite book|last1=Vallery-Radot|first1=René|translator-last=Devonshire|translator-first=R. L.|title=The Life of Pasteur|date=1919|publisher=Constable & Company|location=London|page=141|url=https://archive.org/stream/in.ernet.dli.2015.173907/2015.173907.The-Life-Of-Pasteur#page/n161/mode/2up}}</ref><ref name="Keim pp. 87-88" /> Pasteur concluded that bacteria caused flacherie. The primary cause is currently thought to be viruses.<ref name=Hatcher /> The spread of flacherie could be accidental or hereditary. Hygiene could be used to prevent accidental flacherie. Moths whose digestive cavities did not contain the microorganisms causing flacherie were used to lay eggs, preventing hereditary flacherie.<ref>{{cite book|last1=Vallery-Radot|first1=René|translator-last=Devonshire|translator-first=R. L.|title=The Life of Pasteur|date=1919|publisher=Constable & Company|location=London|page=156|url=https://archive.org/stream/in.ernet.dli.2015.173907/2015.173907.The-Life-Of-Pasteur#page/n175/mode/2up}}</ref>

=== Spontaneous generation ===
[[File:Coldecygne.svg|thumb|Bottle en ''col de cygne'' ([[swan neck flask|swan-neck bottle]]) used by Pasteur]]
[[File:Louis Pasteur Experiment.svg|thumb|Louis Pasteur's pasteurization experiment illustrates the fact that the spoilage of liquid was caused by particles in the air rather than the air itself. These experiments were important pieces of evidence supporting the germ theory of disease.]]
Following his fermentation experiments, Pasteur demonstrated that the skin of grapes was the natural source of yeasts, and that sterilized grapes and grape juice never fermented. He drew grape juice from under the skin with sterilized needles, and also covered grapes with sterilized cloth. Both experiments could not produce wine in sterilized containers.<ref name=Ligon />

His findings and ideas were against the prevailing notion of [[spontaneous generation]]. He received a particularly stern criticism from [[Félix Archimède Pouchet]], who was director of the [[Muséum d'Histoire Naturelle de Rouen|Rouen Museum of Natural History]]. To settle the debate between the eminent scientists, the French Academy of Sciences offered the Alhumbert Prize carrying 2,500 [[francs]] to whoever could experimentally demonstrate for or against the doctrine.<ref name=Magner>{{cite book|last1=Magner|first1=Lois N.|title=History of the Life Sciences|year=2002|publisher=Marcel Dekker|location=New York|isbn=978-0-203-91100-6|pages=251–252|edition=3|url=https://books.google.com/books?id=YKJ6gVYbrGwC&q=Pasteur+spontaneous+generation}}</ref><ref>{{cite journal|last1=Roll-Hansen|first1=Nils|title=Experimental Method and Spontaneous Generation: The Controversy between Pasteur and Pouchet, 1859–64|journal=Journal of the History of Medicine and Allied Sciences|year=1979|volume=XXXIV|issue=3|pages=273–292|doi=10.1093/jhmas/XXXIV.3.273|pmid=383780|s2cid=39800747|url=http://pdfs.semanticscholar.org/ac3d/ed2ccb23bb9274305eb49bb422979276273f.pdf|archive-url=https://web.archive.org/web/20190303003149/http://pdfs.semanticscholar.org/ac3d/ed2ccb23bb9274305eb49bb422979276273f.pdf|url-status=dead|archive-date=3 March 2019}}</ref><ref>{{cite journal|last1=Farley|first1=J|last2=Geison|first2=GL|title=Science, politics and spontaneous generation in nineteenth-century France: the Pasteur-Pouchet debate|journal=Bulletin of the History of Medicine|year=1974|volume=48|issue=2|pages=161–198|pmid=4617616}}</ref>

Pouchet stated that air everywhere could cause spontaneous generation of living organisms in liquids.<ref>{{cite book|last1=Keim|first1=Albert|last2=Lumet|first2=Louis|title=Louis Pasteur|date=1914|publisher=Frederick A. Stokes Company|pages=64|url=https://archive.org/stream/louispasteur00keim#page/64/mode/2up}}</ref> In the late 1850s, he performed experiments and claimed that they were evidence of spontaneous generation.<ref name="porter" /><ref name=Magner /> [[Francesco Redi]] and [[Lazzaro Spallanzani]] had provided some evidence against spontaneous generation in the 17th and 18th centuries, respectively. Spallanzani's experiments in 1765 suggested that air contaminated broths with bacteria. In the 1860s, Pasteur repeated Spallanzani's experiments, but Pouchet reported a different result using a different broth.<ref name=Berche />

Pasteur performed several experiments to disprove spontaneous generation. He placed boiled liquid in a flask and let hot air enter the flask. Then he closed the flask, and no organisms grew in it.<ref name="porter" /> In another experiment, when he opened flasks containing boiled liquid, dust entered the flasks, causing organisms to grow in some of them. The number of flasks in which organisms grew was lower at higher altitudes, showing that air at high altitudes contained less dust and fewer organisms.<ref name=Ligon /><ref>{{cite book|last1=Vallery-Radot|first1=René|translator-last=Devonshire|translator-first=R. L.|title=The Life of Pasteur|date=1919|publisher=Constable & Company|location=London|pages=96–98|url=https://archive.org/stream/in.ernet.dli.2015.173907/2015.173907.The-Life-Of-Pasteur#page/n117/mode/2up}}</ref> Pasteur also used [[swan neck flask]]s containing a fermentable liquid. Air was allowed to enter the flask via a long curving tube that made dust particles stick to it. Nothing grew in the broths unless the flasks were tilted, making the liquid touch the contaminated walls of the neck. This showed that the living organisms that grew in such broths came from outside, on dust, rather than spontaneously generating within the liquid or from the action of pure air.<ref name=Ligon /><ref>{{cite book|last1=Keim|first1=Albert|last2=Lumet|first2=Louis|title=Louis Pasteur|date=1914|publisher=Frederick A. Stokes Company|pages=63–67|url=https://archive.org/stream/louispasteur00keim#page/62/mode/2up}}</ref>

These were some of the most important experiments disproving the theory of spontaneous generation. Pasteur gave a series of five presentations of his findings before the French Academy of Sciences in 1881, which were published in 1882 as ''Mémoire'' ''Sur les corpuscules organisés qui existent dans l'atmosphère: Examen de la doctrine des générations spontanées'' (''Account of Organized Corpuscles Existing in the Atmosphere: Examining the Doctrine of Spontaneous Generation'').<ref>{{Cite web|last=Pasteur|first=Louis|year=1882|title=Mémoire sur les corpuscules organisés qui existent dans l'atmosphère: examen de la doctrine des générations spontanées|url=https://wellcomecollection.org/works/njdg2696|url-status=live|access-date=1 May 2021|website=Wellcome Collection|language=en|archive-date=1 May 2021|archive-url=https://web.archive.org/web/20210501062347/https://wellcomecollection.org/works/njdg2696}}</ref><ref>{{Cite journal|last=Carter|first=K. C.|year=1991|title=The development of Pasteur's concept of disease causation and the emergence of specific causes in nineteenth-century medicine|url=https://pubmed.ncbi.nlm.nih.gov/1802317|journal=Bulletin of the History of Medicine|volume=65|issue=4|pages=528–548|jstor=44442642|pmid=1802317|access-date=1 May 2021|archive-date=25 January 2022|archive-url=https://web.archive.org/web/20220125231811/https://pubmed.ncbi.nlm.nih.gov/1802317/|url-status=live}}</ref> Pasteur won the Alhumbert Prize in 1862.<ref name="porter">{{cite journal|last1=Porter|first1=JR|title=Louis Pasteur: achievements and disappointments, 1861.|journal=Bacteriological Reviews|year=1961|volume=25|issue=4|pages=389–403|pmid=14037390|pmc=441122|doi=10.1128/MMBR.25.4.389-403.1961}}</ref> He concluded that:{{blockquote|Never will the doctrine of spontaneous generation recover from the mortal blow of this simple experiment. There is no known circumstance in which it can be confirmed that microscopic beings came into the world without germs, without parents similar to themselves.<ref name="Ligon" /><ref name="Schwartz" />}}

=== Silkworm disease ===

In 1865, [[Jean-Baptiste Dumas]], chemist, senator and former Minister of Agriculture and Commerce, asked Pasteur to study a new disease that was decimating [[Bombyx mori|silkworm]] farms from the south of France and Europe, the [[pébrine]], characterized on a macroscopic scale by black spots and on a microscopic scale by the "[[Emilio Cornalia|Cornalia]] corpuscles". Pasteur accepted and made five long stays in [[Alès]], between 7 June 1865 and 1869.<ref>Jimmy Drulhon, ''Louis Pasteur. Five years in the Cévennes'', Ed. Hermann, 2009. Pasteur stayed and carried out his scientific work at the [[magnanerie]] of Pont Gisquet, on the road to Saint-Jean-du-Pin.[https://www.google.fr/maps/@44.121694,4.059807,3a,75y,179.7h,70.21t/data=!3m4!1e1!3m2!1sufDCWdKLIc2BJ7ebZ8HMrg!2e0 See Google Street.] {{Webarchive|url=https://web.archive.org/web/20220407210606/https://www.google.fr/maps/@44.121694,4.059807,3a,75y,179.7h,70.21t/data=!3m4!1e1!3m2!1sufDCWdKLIc2BJ7ebZ8HMrg!2e0|date=7 April 2022}}</ref>

==== Initial errors ====
Arriving in Alès, Pasteur familiarized himself with pébrine and also<ref>"He had known it [= flacherie] for a long time, since his first stay in the South in 1865, where one of the two farms that had served as a starting point departure to his deductions was affected by this disease, at the same time as that of the corpuscles." Émile Duclaux, ''Pasteur, Histoire d'un esprit'', pp. 218–219, available on [https://gallica.bnf.fr/ark:/12148/bpt6k764468/f223.table Gallica] {{Webarchive|url=https://web.archive.org/web/20220126152716/https://gallica.bnf.fr/ark:/12148/bpt6k764468/f223.table |date=26 January 2022 }}.</ref> with another disease of the silkworm, known earlier<ref>"This denomination of ''white-dead'', used by the Abbé de Sauvages and several other writers, is inaccurate; this is why I thought it necessary to add that of ''dead-flats'', vulgarly used in several departments, and which designates very well the state of softness and flaccidity in which the worms dead of this disease are found. " Pierre Hubert Nysten, ''Research on the diseases of silkworms'', Paris, 1808, p. 5, available on [https://books.google.com/books?id=1tRIAAAAIAAJ&pg=PA12 Google Books].</ref> than pebrine: [[flacherie]] or dead-flat disease. Contrary, for example, to [[Jean Louis Armand de Quatrefages de Bréau|Quatrefages]], who coined the new word ''pébrine'',<ref>See account of Quatrefages reproduced in L. Pasteur, ''Études sur la maladie des vers à soie'', Paris, 1870, Complete Works of Pasteur, t. 4, p. 27, [https://gallica.bnf.fr/ark:/12148/bpt6k73599/f40.table online] {{Webarchive|url=https://web.archive.org/web/20220126152711/https://gallica.bnf.fr/ark:/12148/bpt6k73599/f40.table |date=26 January 2022 }}.</ref> Pasteur made the mistake of believing that the two diseases were the same and even that most of the diseases of silkworms known up to that time were identical with each other and with pébrine.<ref>"But the cases of association were so frequent, precisely because the disease of the corpuscles was so widespread, that Pasteur had thought that the two conditions were linked to each other and should disappear together. " (Émile Duclaux, ''Pasteur, Histoire d'un esprit'', pp. 218–219, [https://gallica.bnf.fr/ark:/12148/bpt6k764468/f223.table online] {{Webarchive|url=https://web.archive.org/web/20220126152716/https://gallica.bnf.fr/ark:/12148/bpt6k764468/f223.table |date=26 January 2022 }}.) Pasteur expressed this opinion, in particular in " Nouvelles études sur la maladie des vers à soie ", Comptes rendus de l'Académie des sciences, t. 63 (1866), pp. 126–142: "I am very much inclined to believe that there is no actual actual disease of silkworms. The disease complained of seems to me to have always existed, but to a lesser degree. (...) Furthermore, I have serious grounds for believing that most of the diseases of the silkworm which have been known for a long time are linked to the one which occupies us, muscardine and, perhaps, grasserie excepted. (p. 136). Available at [https://gallica.bnf.fr/ark:/12148/bpt6k30204/f136.table Gallica] {{Webarchive|url=https://web.archive.org/web/20220126152722/https://gallica.bnf.fr/ark:/12148/bpt6k30204/f136.table |date=26 January 2022 }}. Same thing in a letter of June 27, 1866, to Dumas: "all the other so-called ancient diseases of the silkworm, minus the ''muscardine'' and perhaps the ''grasserie'', such as the disease of '' motrs -flats'', ''petits'', ''passis'', ''arpians'', are only forms of the actual disease. " (Pasteur, ''Correspondance'', t. 2, p. 265. Quoted by Ph. Decourt, ''Les vérités indésirables'', Paris, 1989, p. 173, and by P. Pinet, ''Pasteur et la phiolosophie'', Paris, 2004, p. 158.</ref> It was in letters of 30 April and 21 May 1867 to Dumas that he first made the distinction between pébrine and flacherie.<ref>"Sur la maladie des vers à soie. Lettre de M. L. Pasteur à M. Dumas", Comptes rendus de l'Académie des sciences, meeting of 3 June 1867, t. 64, p. 1113. Available at [https://gallica.bnf.fr/ark:/12148/bpt6k3021f/f1122.table Gallica] {{Webarchive|url=https://web.archive.org/web/20220407215406/https://gallica.bnf.fr/ark:/12148/bpt6k3021f/f1122.table |date=7 April 2022 }}.</ref>

He made another mistake: he began by denying the "parasitic" (microbial) nature of pébrine, which several scholars (notably [[Antoine Béchamp]])<ref>Philippe Decourt, ''Les vérités indésirables'', Paris, 1989, pp. 165–193, accuses Pasteur of a denial of justice towards Antoine Béchamp, who studied pebrine at the same time as Pasteur and immediately affirmed the parasitic nature of the disease.</ref> considered well established. Even a note published on 27 August 1866 by [[Édouard-Gérard Balbiani|Balbiani]],<ref>Balbiani, Balbiani, " Recherches sur les corpuscules de la pébrine et sur leur mode de propagation ", Comptes rendus de l'Académie des Sciences, session of 27 August 1866, vol. 63 (1866), pp. 388–391, available at [https://gallica.bnf.fr/ark:/12148/bpt6k30204/f388.table Gallica] {{Webarchive|url=https://web.archive.org/web/20220126152715/https://gallica.bnf.fr/ark:/12148/bpt6k30204/f388.table |date=26 January 2022 }}. Balbiani begins in this manner: "Among all the contradictory opinions which have been expressed on the nature of the corpuscles of the pébrine, the most debatable, in my opinion, is that which consists in assimilating them to anatomical elements either normal, or more or less altered., or to morbid products such as pus globules, etc. This opinion was refuted more than eight years ago by Professor Lebert (...); but I believe I can also bring, against the way of seeing cited above, more decisive proofs, based on the observation of the phenomena which these corpuscles present in their evolution, phenomena which put beyond doubt their close relationship with the parasitic organisms. known under the name of ''Psorospermia''".</ref> which Pasteur at first seemed to welcome favourably<ref>"As for the opinions expressed by Mr. Balbiani on the nature of the corpuscles, although I do not share them, I will take great care to examine them, for two reasons: because they are from a skilful observer, and because I still only have preconceived views on the objects they concern, to which I do not agree more than reason. There is more: I earnestly hope that the ideas of MM. Balbiani and Leydig are true (...)". Pasteur, "Observations au sujet d'une Note de M. Balbiani relative à la maladie des vers à soie", ''Comptes rendus de l'Académie des Sciences'', meeting of 10 September 1866, vol. 63 (1866), pp. 441–443.</ref> had no effect, at least immediately.<ref>On 29 May 1867, Pasteur wrote to Dumas again: "Despite all that I would have to say about the notes of Béchamp, Estor, Balbiani and on the articles that the first two insert in the ''Messager du Midi'', I take your advice, I do not answer. If you knew how erroneous it is to say that this disease is not constitutional and only parasitic. Its essential character is precisely its constitutional character. " (Quoted by Ph. Decourt, ''Les vérités indésirables'', Paris, 1989, p. 190.)</ref> "Pasteur is mistaken. He would only change his mind in the course of 1867".<ref>P. Debré, ''Louis Pasteur'', Flammarion, 1994, p. 219. In his ''Études sur la maladie des vers à soie'' (''Studies on silkworm disease''), published in 1870 (Pasteur's Complete Works, vol. 4, available at [https://gallica.bnf.fr/ark:/12148/bpt6k73599 Gallica] {{Webarchive|url=https://web.archive.org/web/20220126152720/https://gallica.bnf.fr/ark:/12148/bpt6k73599 |date=26 January 2022 }}), Pasteur reports that he consulted Leydig on the question of the living nature of corpuscles. (One of his letters to Leydig is from December 1866.) He admits that "in substance" he adopted the opinions of Leydig and Balbiani, but he contradicts them on the question of the mode of formation of the corpuscles (pp. 135, 137 and 138). In 1884, Balbiani will examine Pasteur's theory on the development of corpuscles and will conclude as follows: "I believe that it is useless to dwell any longer on the observations of M. Pasteur, which I think I can characterize with a single word by saying that their author proves in it how little he is familiar with the researches of biology. But with this reservation, I do justice to his work, which has rendered sericulture farmers a real service by enabling them to recognize a healthy seed from a diseased seed. " (G. Balbiani, ''Leçons sus les sporozoaires'', Paris, 1884, pp. 160–163, [https://archive.org/details/leonssurlesspo00balb online.]) On Pasteur's errors in the study of silkworms and his own judgment on these errors, see Richard Moreau, "Le dernier pli cacheté de Louis Pasteur à l'Académie des sciences", La vie des sciences, ''Comptes rendus'', série générale, t. 6, 1989, n° 5, pp. 403–434, [https://www.academie-sciences.fr/archivage_site/fondations/lp_pdf/Plis_07_1869.pdf online] {{Webarchive|url=https://web.archive.org/web/20220130215818/https://www.academie-sciences.fr/archivage_site/fondations/lp_pdf/Plis_07_1869.pdf |date=30 January 2022 }}.</ref>

==== Victory over pébrine ====

At a time where Pasteur had not yet understood the cause of the pébrine, he propagated an effective process to stop infections: a sample of chrysalises was chosen, they were crushed and the corpuscles were searched for in the crushed material; if the proportion of corpuscular pupae in the sample was very low, the chamber was considered good for reproduction.<ref>Louis Pasteur, ''Études sur la maladie des vers à soie''; Œuvres complètes, t. 4, pp. 166–167, available at [https://gallica.bnf.fr/ark:/12148/bpt6k73599/f195.table Gallica] {{Webarchive|url=https://web.archive.org/web/20220126152711/https://gallica.bnf.fr/ark:/12148/bpt6k73599/f195.table |date=26 January 2022 }}.</ref> This method of sorting "seeds" (eggs) is close to a method that Osimo had proposed a few years earlier, but whose trials had not been conclusive.<ref>Pasteur mentions Osimo's ideas in Louis Pasteur, ''Études sur la maladie des vers à soie'', Œuvres complètes, t. 4, pp. 38–39, available at [https://gallica.bnf.fr/ark:/12148/bpt6k73599/f57.table Gallica] {{Webarchive|url=https://web.archive.org/web/20220126152724/https://gallica.bnf.fr/ark:/12148/bpt6k73599/f57.table |date=26 January 2022 }}. Summarizing a development by Émile Duclaux (Émile Duclaux, ''Pasteur, histoire d'un esprit'', Sceaux, 1896, p. 198, available at [https://gallica.bnf.fr/ark:/12148 /bpt6k764468/f203.notice Gallica] {{Webarchive|url=https://web.archive.org/web/20070706205222/http://gallica.bnf.fr/ark:/12148 |date=6 July 2007 }}), P. Debré wrote that Pasteur was "led to propose a seed sorting method almost identical to that recommended a few years earlier by Orcino [read: Osimo]. If the latter had failed, asserts Pasteur, it was through a lack of confidence; which, of course, is not his case. " P. Debré, ''Louis Pasteur'', Flammarion, 1994, p. 210.</ref> By this process, Pasteur curbed pébrine and saved much of the silk industry in the Cévennes.<ref>Patrice Debré, Louis Pasteur, Flammarion, 1995, p. 246.</ref><ref>Elie Reynier, ''La soie en Vivarais'', 1921, [http://www.nemausensis.com/ardeche/soie/LaMaladie.htm online] {{Webarchive|url=https://web.archive.org/web/20220104215910/http://www.nemausensis.com/ardeche/soie/LaMaladie.htm |date=4 January 2022 }}.</ref>

==== Flacherie resists ====
[[File:Pasteur by Lafon 1883.jpg|thumb|Portrait of Louis Pasteur by François Lafon (1883)]]
In 1878, at the ''Congrès international séricicole'', Pasteur admitted that "if pébrine is overcome, flacherie still exerts its ravages". He attributed the persistence of flacherie to the fact that the farmers had not followed his advice.<ref>(''Comptes rendus sténographiques du Congrès international séricicole, tenu à Paris du 5 au 10 septembre 1878''; Paris, 1879, pp. 27–38. ''Œuvres complètes'' of Pasteur, t. 4, pp. 698–713, spec. 699 and 713; available on [http://gallica2.bnf.fr/ark:/12148/bpt6k73599.image.f746.langEN.tableDesMatieres Gallica] {{Webarchive|url=https://archive.today/20130801101453/http://gallica2.bnf.fr/ark:/12148/bpt6k73599.image.f746.langEN.tableDesMatieres |date=1 August 2013 }}.</ref>

In 1884, [[Édouard-Gérard Balbiani|Balbiani]],<ref>G. Balbiani, ''Leçons sus les sporozoaires'', Paris, 1884, pp. 160–163, 167–168,  [https://archive.org/details/leonssurlesspo00balb online].</ref> who disregarded the theoretical value of Pasteur's work on silkworm diseases, acknowledged that his practical process had remedied the ravages of pébrine, but added that this result tended to be counterbalanced by the development of flacherie, which was less well known and more difficult to prevent.

Despite Pasteur's success against pébrine, French sericulture had not been saved from damage. (See [[:fr:Sériciculture]] in the French Wikipedia.){{circular reference|date=March 2025}}

=== Immunology and vaccination ===
==== Chicken cholera ====
Pasteur's first work on vaccine development was on [[chicken cholera]]. He received the bacteria samples (later called ''Pasteurella multocida'' after him) from [[Jean Joseph Henri Toussaint|Henry Toussaint]].<ref name="Plotkin pp. 35-36">{{cite book|editor1-last=Plotkin|editor1-first=Stanley A.|title=History of Vaccine Development|date=2011|publisher=Springer|isbn=978-1-4419-1339-5|pages=35–36|url=https://books.google.com/books?id=Wf2jS_4lCOAC&pg=PA39}}</ref> Being unable to conduct the experiments himself due to a stroke in 1868,<ref>{{cite book |last1=Descour |first1=L. |title=Pasteur and his work |date=1922 |publisher=Frederick A. Stokes Company |location=New York}}</ref> Pasteur relied heavily on his assistants Emile Roux and Charles Chamberland. The work with chicken cholera was initiated in 1877, and by the next year, Roux was able to maintain a stable culture using broths.<ref name=":0">{{Cite journal|last=Barranco|first=Caroline|date=28 September 2020|title=The first live attenuated vaccines|url=https://www.nature.com/articles/d42859-020-00008-5|journal=Nature Milestones|language=en|access-date=30 April 2021|archive-date=2 August 2021|archive-url=https://web.archive.org/web/20210802072726/https://www.nature.com/articles/d42859-020-00008-5|url-status=live}}</ref> As documented later by Pasteur in his notebook in March of 1880,<ref>{{cite journal |last1=Murnane |first1=John P |last2=Probert |first2=Rebecca |title=The relationship between Rose Anna Shedlock (c1850-1878) and Emile Roux (1853-1933) |journal=Journal of Medical Biography |date=August 25, 2024 |volume=online first |pages=1–8 |doi=10.1177/09677720241273568 |pmid=39183561 |doi-access=free |pmc=12056263 }}</ref><ref>{{cite book |last1=Bazin |first1=Herve |title=Vaccination: a History |date=2011 |publisher=John Libby |location=Esher, United Kingdom}}</ref> in October of 1879, being delayed in returning to the laboratory due to his daughter’s wedding and ill health, he instructed Roux to start a new chicken cholera culture using bacteria from a culture that had sat since July. The two chickens inoculated with this new culture showed some symptoms of infection, but instead of the infections being fatal, as they usually were, the chickens recovered completely. After further incubation of the culture for an additional 8 days, Roux again inoculated the same two chickens. As was also noted by Pasteur in his notebook in March of 1880, and contrary to some accounts, this time the chickens died. Thus, although the attenuated bacteria did not provide immunity, these experiments provided important clues as to how bacteria could be artificially attenuated in the laboratory. As a result, upon Pasteur’s return to the laboratory, the focus of the research was directed at creating a vaccine through attenuation. 

In February of 1880, Pasteur presented his results to the French Academy of Sciences as "''Sur les maladies virulentes et en particulier sur la maladie appelée vulgairement choléra des poules'' (On virulent diseases, and in particular on the disease commonly called chicken cholera)" and published it in the academy's journal (''[[Comptes rendus de l'Académie des Sciences|Comptes-Rendus hebdomadaires des séances de l'Académie des Sciences]]''). He attributed that the bacteria were weakened by contact with oxygen.<ref name="Plotkin pp. 35-36" /> He explained that bacteria kept in sealed containers never lost their virulence, and only those exposed to air in culture media could be used as vaccine. Pasteur introduced the term "attenuation" for this weakening of virulence as he presented before the academy, saying:{{blockquote|We can diminish the microbe's virulence by changing the mode of culturing. This is the crucial point of my subject. I ask the Academy not to criticize, for the time being, the confidence of my proceedings that permit me to determine the microbe's attenuation, in order to save the independence of my studies and to better assure their progress... [In conclusion] I would like to point out to the Academy two main consequences to the facts presented: the hope to culture all microbes and to find a vaccine for all infectious diseases that have repeatedly afflicted humanity, and are a major burden on agriculture and breeding of domestic animals.<ref name=":1">{{Cite journal|last=Smith|first=Kendall A.|year=2012|title=Louis pasteur, the father of immunology?|journal=Frontiers in Immunology|volume=3|pages=68|doi=10.3389/fimmu.2012.00068|pmc=3342039|pmid=22566949|doi-access=free}}</ref> }}

In fact, Pasteur's vaccine against chicken cholera did not consistently produce immunity, and has subsequently been proven to be ineffective.<ref>"This way, which the genius of Pasteur had opened and which became so fruitful, soon proved to be closed with regard to the anti-pasteurellic vaccination of the hen. Difficulties arose in the regularity of attenuation and maintenance of virulence to a definite and fixed degree." (G. Lesbouyries, ''La pathologie des oiseaux'', Paris, 1941, p. 340; quoted by Hervé Bazin, ''L'Histoire des vaccinations'', John Libbey Eurotext, 2008, p. 155.)</ref>

==== Anthrax ====
Following the results with chicken cholera, Pasteur eventually utilized the immunization method developed for chicken cholera to create a vaccine for [[anthrax]], which affected [[cattle]]. In 1877, Pasteur had earlier directed his laboratory to culture the bacteria from the blood of infected animals, following the discovery of the bacterium by Robert Koch.<ref name=":1" />
[[File:Albert Edelfelt - Louis Pasteur - 1885.jpg|thumb|''Louis Pasteur in his laboratory'', painting by [[Albert Edelfelt|A. Edelfeldt]] in 1885]] When animals were infected with the bacteria, anthrax occurred, proving that the bacteria was the cause of the disease.<ref>{{cite book|last1=Keim|first1=Albert|last2=Lumet|first2=Louis|title=Louis Pasteur|date=1914|publisher=Frederick A. Stokes Company|pages=123–125|url=https://archive.org/stream/louispasteur00keim#page/122/mode/2up}}</ref> Many cattle were dying of anthrax in "cursed fields".<ref name=Schwartz /> Pasteur was told that sheep that died from anthrax were buried in the field. Pasteur thought that earthworms might have brought the bacteria to the surface. He found anthrax bacteria in earthworms' excrement, showing that he was correct.<ref name=Schwartz /> He told the farmers not to bury dead animals in the fields.<ref>{{cite book|last1=Vallery-Radot|first1=René|translator-last=Devonshire|translator-first=R. L.|title=The Life of Pasteur|date=1919|publisher=Constable & Company|location=London|pages=303–305|url=https://archive.org/stream/in.ernet.dli.2015.173907/2015.173907.The-Life-Of-Pasteur#page/n323/mode/2up}}</ref> 

Pasteur's interest in creating a vaccine for anthrax was greatly stimulated when on 12 July 1880, Henri Bouley read before the French Academy of Sciences a report from [[Jean Joseph Henri Toussaint|Henry Toussaint]], a [[veterinary surgeon]], who was not a member of the academy. Toussaint had developed anthrax vaccine by killing the bacilli by heating at 55&nbsp;°C for 10  minutes. He tested his vaccine on eight dogs and 11 sheep, half of which died after inoculation. It was not a great success. Upon hearing the news, Pasteur immediately wrote to the academy that he could not believe that dead vaccine would work and that Toussaint's claim "overturns all the ideas I had on viruses, vaccines, etc."<ref name=":1" /> Following Pasteur's criticism, Toussaint switched to [[carbolic acid]] (phenol) to kill anthrax bacilli and tested the vaccine on sheep in August 1880. Pasteur thought that this type of killed vaccine should not work because he believed that attenuated bacteria used up nutrients that the bacteria needed to grow. He thought oxidizing bacteria when sitting in culture broth for prolonged periods made them less virulent.<ref>{{cite book|last1=Tizard|first1=Ian|editor1-last=Schultz|editor1-first=Ronald D.|title=Veterinary Vaccines and Diagnostics|date=1998|publisher=Academic Press|pages=12–14|chapter-url=https://books.google.com/books?id=i4s1YpGVFB8C&pg=PA12|chapter=Grease, Anthraxgate, and Kennel Cough: A Revisionist History of Early Veterinary Vaccines|isbn=978-0-08-052683-6}}</ref>

However, Pasteur's laboratory found that anthrax bacillus was not easily weakened by culturing in air as it formed spores – unlike chicken cholera bacillus. In early 1881, his laboratory discovered that growing anthrax bacilli at about 42&nbsp;°C made them unable to produce spores,<ref name="Bazin p. 196">{{cite book|last1=Bazin|first1=Hervé|title=Vaccinations: a History: From Lady Montagu to Jenner and genetic engineering|date=2011|publisher=John Libbey Eurotext|isbn=978-2-7420-1344-9|pages=196–197|url=https://books.google.com/books?id=IC8QBAAAQBAJ&pg=PA196}}</ref> and he described this method in a speech to the French Academy of Sciences on 28 February.<ref>{{cite journal|last1=Pasteur|first1=L.|last2=Chamberland|first2=C.|last3=Roux|first3=E.|title=Le vaccin de charbon|journal=Comptes Rendus Hebdomadaires des Séances de l'Académie des Sciences|year=1881|volume=92|pages=666–668|url=http://gallica.bnf.fr/ark:/12148/bpt6k7351t/f665.item.r=+COMPTES+RENDUS+++DES+S%C3%89ANCES+DE+L.langFR.zoom|language=fr|access-date=4 March 2017|archive-date=4 March 2017|archive-url=https://web.archive.org/web/20170304201227/http://gallica.bnf.fr/ark:/12148/bpt6k7351t/f665.item.r=+COMPTES+RENDUS+++DES+S%C3%89ANCES+DE+L.langFR.zoom|url-status=live}}</ref> On 21 March, despite inconsistent results, he announced successful vaccination of sheep. To this news, veterinarian Hippolyte Rossignol proposed that the Société d'agriculture de Melun organize an experiment to test Pasteur's vaccine.  Pasteur signed an agreement accepting the challenge on 28 April. Pasteur's assistants, Roux and Chamberland, who were assigned the task of conducting the trial, were concerned about the unreliability of the attenuated vaccine, and therefore Chamberland secretly prepared an alternative vaccine using chemical inactivation.<ref name="Geison1995" /> Without divulging their method of preparing the vaccine to anyone but Pasteur, Roux and Chamberland performed the public experiment on May at Pouilly-le-Fort.<ref name="Geison1995" /> 58 sheep, 2 goats and 10 cattle were used, half of which were given the vaccine on 5 and 17 May; while the other half was untreated.<ref name=":2">{{Cite journal|last1=Pasteur|first1=Louis|last2=Chamberland|last3=Roux|year=2002|title=Summary report of the experiments conducted at Pouilly-le-Fort, near Melun, on the anthrax vaccination, 1881.|journal=The Yale Journal of Biology and Medicine|volume=75|issue=1|pages=59–62|pmc=2588695|pmid=12074483}}</ref> On 31 May, Roux and Chamberland next injected the animals with the fresh virulent culture of anthrax bacillus. The official result was observed and analyzed on 2 June in the presence of over 200 spectators, with Pasteur himself in attendance. The results were as Pasteur had bravely predicted: "I hypothesized that the six vaccinated cows would not become very ill, while the four unvaccinated cows would perish or at least become very ill."<ref name=":2" /> However, all vaccinated sheep and goats survived, while unvaccinated ones had died or were dying before the viewers.<ref>{{Cite journal|last=Smith|first=Kendall A.|year=2005|title=Wanted, an Anthrax vaccine: Dead or Alive?|journal=Medical Immunology|volume=4|issue=1|pages=5|doi=10.1186/1476-9433-4-5|pmc=1087873|pmid=15836780 |doi-access=free }}</ref> His report to the French Academy of Sciences on 13 June concludes:{{blockquote|[By] looking at everything from the scientific point of view, the development of a vaccination against anthrax constitutes significant progress beyond the first vaccine developed by Jenner, since the latter had never been obtained experimentally.<ref name=":2" />}}Pasteur did not directly disclose how he prepared the vaccines used at Pouilly-le-Fort.<ref>{{cite book|editor1-last=Plotkin|editor1-first=Stanley A.|title=History of Vaccine Development|date=2011|publisher=Springer|isbn=978-1-4419-1339-5|pages=37–38|url=https://books.google.com/books?id=Wf2jS_4lCOAC&pg=PA37}}</ref><ref name="Bazin p. 196" /> Although his report indicated it as a "live vaccine",<ref name=":2" /> his laboratory notebooks show that he actually used [[potassium dichromate]]-killed vaccine, as developed by Chamberland, quite similar to Toussaint's method.<ref name="Giese">{{cite book|editor1-last=Giese|editor1-first=Matthias|title=Molecular Vaccines: From Prophylaxis to Therapy|volume=1|date=2013|publisher=Springer|isbn=978-3-7091-1419-3|page=4|url=https://books.google.com/books?id=CLm8BAAAQBAJ&pg=PA4}}</ref><ref name="cohn">{{cite web| url=http://eri.louisville.edu/~eri/fos/interest1.html| title=Pasteur| author=Cohn, David V| publisher=University of Louisville| date=18 December 2006| access-date=2 December 2007| quote=Fortunately, Pasteur's colleagues Chamberland and Roux followed up the results of a research physician Jean-Joseph-Henri Toussaint, who had reported a year earlier that carbolic-acid/heated anthrax serum would immunize against anthrax. These results were difficult to reproduce and discarded although, as it turned out, Toussaint had been on the right track. This led Pasteur and his assistants to substitute an anthrax vaccine prepared by a method similar to that of Toussaint and different from what Pasteur had announced.| archive-date=23 March 2017| archive-url=https://web.archive.org/web/20170323234134/http://eri.louisville.edu/~eri/fos/interest1.html| url-status=live}}</ref><ref>{{cite book| author= Loir, A| title=Le mouvement sanitaire| year=1938| pages=18, 160| chapter=A l'ombre de Pasteur|chapter-url=https://books.google.com/books?id=WElmkgEACAAJ}}</ref>

The notion of a weak form of a disease causing immunity to the virulent version was not new; this had been known for a long time for [[smallpox]]. Inoculation with smallpox ([[variolation]]) was known to result in a much less severe disease, and greatly reduced mortality, in comparison with the naturally acquired disease.<ref>{{cite book|editor1-last=Artenstein|editor1-first=Andrew W.|title=Vaccines: A Biography|date=2009|publisher=Springer|isbn=978-1-4419-1108-7|page=10|url=https://books.google.com/books?id=ewdL8ilILZAC&pg=PA10}}</ref> [[Edward Jenner]] had also studied [[vaccination]] using [[cowpox]] (''[[vaccinia]]'') to give cross-immunity to smallpox in the late 1790s, and by the early 1800s vaccination had spread to most of Europe.<ref>{{cite book|last1=Bazin|first1=Hervé|title=Vaccinations: a History: From Lady Montagu to Jenner and genetic engineering|date=2011|publisher=John Libbey Eurotext|isbn=978-2-7420-1344-9|pages=66–67, 82|url=https://books.google.com/books?id=IC8QBAAAQBAJ&pg=PA66}}</ref>

The difference between smallpox vaccination and [[anthrax]] or [[chicken cholera]] vaccination was that the latter two disease organisms had been artificially weakened, so a naturally weak form of the disease organism did not need to be found.<ref name=Giese /> Pasteur's development of artificially weakened pathogens revolutionized work in infectious diseases, and he gave these artificially weakened diseases the generic name of "[[vaccine]]s", in honour of Jenner's discovery.<ref>{{cite book|last1=Vallery-Radot|first1=René|translator-last=Devonshire|translator-first=R. L.|title=The Life of Pasteur|date=1919|publisher=Constable & Company|location=London|page=332|url=https://archive.org/stream/in.ernet.dli.2015.173907/2015.173907.The-Life-Of-Pasteur#page/n351/mode/2up}}</ref>

{{Main|Koch–Pasteur rivalry}}
In 1876, [[Robert Koch]] had shown that ''[[Bacillus anthracis]]'' caused anthrax.<ref name="De Paolo">{{cite book|last1=De Paolo|first1=Charles|title=Epidemic Disease and Human Understanding: A Historical Analysis of Scientific and Other Writings|date=2006|publisher=McFarland|isbn=978-0-7864-2506-8|pages=103, 111–114|url=https://books.google.com/books?id=Xcz7Y9qVGQMC&pg=PA103}}</ref> In his papers published between 1878 and 1880, Pasteur only mentioned Koch's work in a footnote. Koch met Pasteur at the Seventh [[International Medical Congress]] in 1881. A few months later, Koch wrote that Pasteur had used impure cultures and made errors. In 1882, Pasteur replied to Koch in a speech, to which Koch responded aggressively.<ref name="ullmann" /> Koch stated that Pasteur tested his vaccine on unsuitable animals and that Pasteur's research was not properly scientific.<ref name=Ligon /> In 1882, Koch wrote "On the Anthrax Inoculation", in which he refuted several of Pasteur's conclusions about anthrax and criticized Pasteur for keeping his methods secret, jumping to conclusions, and being imprecise. In 1883, Pasteur wrote that he used cultures prepared in a similar way to his successful fermentation experiments and that Koch misinterpreted statistics and ignored Pasteur's work on silkworms.<ref name="De Paolo" />

==== Swine erysipelas ====
In 1882, Pasteur sent his assistant [[Louis Thuillier]] to southern France because of an [[epizootic]] of [[swine erysipelas]].<ref>{{cite book|editor1-last=Plotkin|editor1-first=Stanley A.|title=History of Vaccine Development|date=2011|publisher=Springer|isbn=978-1-4419-1339-5|page=39|url=https://books.google.com/books?id=Wf2jS_4lCOAC&pg=PA39}}</ref> Thuillier identified the bacillus that caused the disease in March 1883.<ref name=Berche /> Pasteur and Thuillier increased the bacillus's virulence after passing it through pigeons. Then they passed the bacillus through rabbits, weakening it and obtaining a vaccine. Pasteur and Thuillier incorrectly described the bacterium as a figure-eight shape. Roux described the bacterium as stick-shaped in 1884.<ref>{{cite book|last1=Bazin|first1=Hervé|title=Vaccination: A History|date=2011|publisher=John Libbey Eurotext|isbn=978-2-7420-0775-2|page=211|url=https://books.google.com/books?id=orjaA_7sYZQC&pg=PA211}}</ref>

==== Rabies ====
[[File:Louis Pasteur Vanity Fair 8 January 1887.jpg|thumb|upright|Captioned "[[Rabies|Hydrophobia]]", caricature of Pasteur in the London magazine ''[[Vanity Fair (British magazine)|Vanity Fair]]'', January 1887<ref>{{Cite web |title=959.025 {{!}} Collections Online |url=https://collections.thackraymuseum.co.uk/object-959-025 |access-date=2024-05-29 |website=collections.thackraymuseum.co.uk}}</ref>]]
Pasteur's laboratory produced the first vaccine for [[rabies]] using a method developed by his assistant Roux,<ref name="Geison1995" /> which involved growing the virus in rabbits, and then weakening it by drying the affected nerve tissue.<ref name=Schwartz /><ref name="wood">{{cite journal|last1=Wood|first1=Margaret E.|title=Biting Back|url=https://www.sciencehistory.org/distillations/magazine/biting-back|journal=Chemical Heritage Magazine|volume=28|number=2|page=7|access-date=20 March 2018|date=3 June 2016|archive-date=21 March 2018|archive-url=https://web.archive.org/web/20180321130516/https://www.sciencehistory.org/distillations/magazine/biting-back|url-status=live}}</ref> The rabies vaccine was initially created by [[Emile Roux]], a French doctor and a colleague of Pasteur, who had produced a killed vaccine using this method.<ref name=Ligon /> The vaccine had been tested in 50 dogs before its first human trial.<ref>{{cite book|first1= Sue Vander|last1=Hook |title= Louis Pasteur: Groundbreaking Chemist & Biologist |publisher= ABDO|url= https://archive.org/details/louispasteurgrou0000vand|url-access= registration|year=2011 |page=[https://archive.org/details/louispasteurgrou0000vand/page/8 8]|isbn=978-1-61714-783-8 }}</ref><ref>{{cite web|last1=Corole D|first1=Bos|title=Louis Pasteur and the Rabies Virus – Louis Pasteur Meets Joseph Meister|url=https://www.awesomestories.com/asset/view/LOUIS-PASTEUR-MEETS-JOSEPH-MEISTER-Louis-Pasteur-and-the-Rabies-Virus|publisher=Awesome Stories|access-date=22 November 2014|year=2014|archive-date=29 November 2014|archive-url=https://web.archive.org/web/20141129064133/https://www.awesomestories.com/asset/view/LOUIS-PASTEUR-MEETS-JOSEPH-MEISTER-Louis-Pasteur-and-the-Rabies-Virus|url-status=live}}</ref> This vaccine was used on 9-year-old [[Joseph Meister]], on 6 July 1885, after the boy was badly mauled by a rabid dog.<ref name="cohn" /><ref name="wood" /> This was done at some personal risk for Pasteur, since he was not a licensed physician and could have faced prosecution for treating the boy.<ref name=van /> After consulting with physicians, he decided to go ahead with the treatment.<ref name=Wasik /> Over 11 days, Meister received 13 inoculations, each inoculation using viruses that had been weakened for a shorter period of time.<ref name=Jackson /> Three months later he examined Meister and found that he was in good health.<ref name=Wasik /><ref name=trueman>{{cite web|author= Trueman C|title= Louis Pasteur|url= http://www.historylearningsite.co.uk/louis_pasteur.htm|work= HistoryLearningSite.co.uk|access-date= 3 July 2013|archive-date= 20 May 2015|archive-url= https://web.archive.org/web/20150520170850/http://www.historylearningsite.co.uk/louis_pasteur.htm|url-status= live}}</ref> Pasteur was hailed as a hero and the legal matter was not pursued.<ref name=van /> Analysis of his laboratory notebooks shows that Pasteur had treated two people before his vaccination of Meister. One survived but may not actually have had rabies, and the other died of rabies.<ref name=Jackson /><ref>{{cite book|editor1-last=Artenstein|editor1-first=Andrew W.|title=Vaccines: A Biography|date=2009|publisher=Springer|isbn=978-1-4419-1108-7|page=79|url=https://books.google.com/books?id=ewdL8ilILZAC&pg=PA79}}</ref> Pasteur began treatment of Jean-Baptiste Jupille on 20 October 1885, and the treatment was successful.<ref name=Jackson /> Later in 1885, people, including four children from the United States, went to Pasteur's laboratory to be inoculated.<ref name=Wasik /> In 1886, he treated 350 people, of which only one developed rabies.<ref name=Jackson /> The treatment's success laid the foundations for the manufacture of many other vaccines. The first of the Pasteur Institutes was also built on the basis of this achievement.<ref name="cohn" />

In ''[[The Story of San Michele]]'', [[Axel Munthe]] writes of some risks Pasteur undertook in the rabies vaccine research:<ref>{{cite book|last1=Munthe|first1=Axel|title=The Story of San Michele|date=2010|orig-year=First published 1929|publisher=Hachette UK|isbn=978-1-84854-526-7|chapter-url=https://books.google.com/books?id=XOfWJdqYoHYC|chapter=V: Patients}}</ref>
{{blockquote|Pasteur himself was absolutely fearless. Anxious to secure a sample of saliva straight from the jaws of a rabid dog, I once saw him with the glass tube held between his lips draw a few drops of the deadly saliva from the mouth of a rabid bull-dog, held on the table by two assistants, their hands protected by leather gloves.}}

Because of his study in germs, Pasteur encouraged doctors to sanitize their hands and equipment before surgery. Prior to this, few doctors or their assistants practiced these procedures.<ref>{{Cite journal|last=Melin|first=Maxwell David|year=2016|title=The Industrial Revolution and the Advent of Modern Surgery|url=https://ojs.stanford.edu/ojs/index.php/intersect/article/view/819|journal=Intersect: The Stanford Journal of Science, Technology, and Society|language=en|volume=9|issue=2|pages=online (1–13)|access-date=25 August 2021|archive-date=25 August 2021|archive-url=https://web.archive.org/web/20210825051413/https://ojs.stanford.edu/ojs/index.php/intersect/article/view/819|url-status=live}}</ref><ref>{{Cite journal|last=Magerl|first=Mary Ann|year=2008|title=Operating Room Sanitation: Routine Cleaning Versus Terminal Cleaning|url=https://linkinghub.elsevier.com/retrieve/pii/S1556793108000211|journal=Perioperative Nursing Clinics|language=en|volume=3|issue=2|pages=143–148|doi=10.1016/j.cpen.2008.01.007|access-date=25 August 2021|archive-date=26 May 2021|archive-url=https://web.archive.org/web/20210526013701/https://linkinghub.elsevier.com/retrieve/pii/S1556793108000211|url-status=live}}</ref> [[Ignaz Semmelweis]] and [[Joseph Lister]] had earlier practiced hand sanitizing in medical contexts in the 1860s.<ref>{{Cite journal|last1=Vermeil|first1=T.|last2=Peters|first2=A.|last3=Kilpatrick|first3=C.|last4=Pires|first4=D.|last5=Allegranzi|first5=B.|last6=Pittet|first6=D.|year=2019|title=Hand hygiene in hospitals: anatomy of a revolution|url=https://linkinghub.elsevier.com/retrieve/pii/S0195670118304821|journal=Journal of Hospital Infection|language=en|volume=101|issue=4|pages=383–392|doi=10.1016/j.jhin.2018.09.003|pmid=30237118|s2cid=52306024|access-date=25 August 2021|archive-date=19 February 2022|archive-url=https://web.archive.org/web/20220219175842/https://linkinghub.elsevier.com/retrieve/pii/S0195670118304821|url-status=live}}</ref><ref>{{Cite journal|last=Larson|first=E|year=1989|title=Innovations in health care: antisepsis as a case study.|journal=American Journal of Public Health|language=en|volume=79|issue=1|pages=92–99|doi=10.2105/AJPH.79.1.92|pmc=1349481|pmid=2642372}}</ref>

== Controversies ==

A French national hero at age 55, in 1878 Pasteur discreetly told his family to never reveal his laboratory notebooks to anyone. His family obeyed, and all his documents were held and inherited in secrecy. Being that Pasteur did not allow others in his laboratory to keep notebooks,<ref>{{cite book |last1=Descour |first1=L. |title=Pasteur and his work |date=1922 |publisher=Frederick A. Stokes Company |location=New York}}</ref> this secrecy kept many aspects of Pasteur's research unknown until relatively recently. Finally, in 1964 Pasteur's grandson and last surviving male descendant, Pasteur Vallery-Radot, donated the papers to the [[Bibliothèque nationale de France|French national library]]. Yet the papers were restricted for historical studies until the death of Vallery-Radot in 1971. The documents were given a catalogue number only in 1985.<ref>{{cite book|last1=Geison|first1=Gerald L.|title=The Private Science of Louis Pasteur|date=2014|publisher=Princeton University Press|isbn=978-1-4008-6408-9|page=3|url=https://books.google.com/books?id=tEkABAAAQBAJ&pg=PA3}}</ref>

In 1995, the centennial of the death of Louis Pasteur, a historian of science [[Gerald L. Geison]] published an analysis of Pasteur's private notebooks in his ''The Private Science of Louis Pasteur'', and declared that Pasteur had given several misleading accounts and played deceptions in his most important discoveries.<ref name=Geison1995 /><ref>{{cite journal|last1=Altman|first1=Lawrence K|title=Revisionist history sees Pasteur as liar who stole rival's ideas|journal=The New York Times on the Web|year=1995|volume=16|pages=C1, C3|pmid=11647062|url=https://www.nytimes.com/1995/05/16/science/doctor-s-world-revisionist-history-sees-pasteur-liar-who-stole-rival-s-ideas.html|access-date=17 February 2017|archive-date=2 February 2017|archive-url=https://web.archive.org/web/20170202003043/http://www.nytimes.com/1995/05/16/science/doctor-s-world-revisionist-history-sees-pasteur-liar-who-stole-rival-s-ideas.html|url-status=live}}</ref> [[Max Perutz]] published a defense of Pasteur in ''[[The New York Review of Books]]''.<ref>21 December 1995 NY Review of Books [http://www.nybooks.com/articles/archives/1995/dec/21/the-pioneer-defended/] {{Webarchive|url=https://web.archive.org/web/20151029083822/http://www.nybooks.com/articles/archives/1995/dec/21/the-pioneer-defended/|date=29 October 2015}}, letters [http://www.nybooks.com/articles/archives/1996/apr/04/pasteur-and-the-culture-wars-an-exchange/] {{Webarchive|url=https://web.archive.org/web/20150920173420/http://www.nybooks.com/articles/archives/1996/apr/04/pasteur-and-the-culture-wars-an-exchange/|date=20 September 2015}} [http://www.nybooks.com/articles/archives/1997/feb/06/pasteurs-private-science/] {{Webarchive|url=https://web.archive.org/web/20151029083822/http://www.nybooks.com/articles/archives/1995/dec/21/the-pioneer-defended/|date=29 October 2015}}</ref> Based on further examinations of Pasteur's documents, French immunologist Patrice Debré concluded in his book'' Louis Pasteur'' (1998) that, in spite of his genius, Pasteur had some faults. A book review states that Debré "sometimes finds him unfair, combative, arrogant, unattractive in attitude, inflexible and even dogmatic".<ref>{{cite book|last1=Debré|first1=Patrice|title=Louis Pasteur|year=2000|publisher=Johns Hopkins University Press|location=Baltimore|isbn=978-0-8018-6529-9}}</ref><ref>{{cite journal|last1=Kauffman|first1=George B|title=Book Review: Louis, Louis, Louis|journal=American Scientist|year=1999|url=http://www.americanscientist.org/bookshelf/pub/louis-louis-louis|access-date=27 October 2014|archive-date=27 October 2016|archive-url=https://web.archive.org/web/20161027151905/http://www.americanscientist.org/bookshelf/pub/louis-louis-louis|url-status=live}}</ref>

=== Fermentation ===

Scientists before Pasteur had studied fermentation. In the 1830s, [[Charles Cagniard-Latour]], [[Friedrich Traugott Kützing]] and Theodor Schwann used microscopes to study yeasts and concluded that yeasts were living organisms. In 1839, [[Justus von Liebig]], [[Friedrich Wöhler]] and [[Jöns Jacob Berzelius]] stated that yeast was not an organism and was produced when air acted on plant juice.<ref name=Barnett />

In 1855, [[Antoine Béchamp]], Professor of Chemistry at the [[University of Montpellier]], conducted experiments with sucrose solutions and concluded that water was the factor for fermentation.<ref>{{cite journal|last1=Béchamp|first1=A|title=Note sur l'influence que l'eau pure et certaines dissolutions salines exercent sur le sucre de canne|journal=Comptes Rendus Chimie|year=1855|volume=40|pages=436–438}}</ref> He changed his conclusion in 1858, stating that fermentation was directly related to the growth of moulds, which required air for growth. He regarded himself as the first to show the role of microorganisms in fermentation.<ref>{{cite journal|last1=Béchamp|first1=A|title=De l'influence que l'eau pur ou chargée de diverse sels exerce à froid sur the sucre de canne|journal=Comptes Rendus Chimie|year=1858|volume=46|pages=4–47}}</ref><ref name=manchester2007 />

Pasteur started his experiments in 1857 and published his findings in 1858 (April issue of ''Comptes Rendus Chimie'', Béchamp's paper appeared in January issue). Béchamp noted that Pasteur did not bring any novel idea or experiments. On the other hand, Béchamp was probably aware of Pasteur's 1857 preliminary works. With both scientists claiming priority on the discovery, a dispute, extending to several areas, lasted throughout their lives.<ref>{{cite journal|last1=Cadeddu|first1=A|title=The heuristic function of 'error' in the scientific methodology of Louis Pasteur: the case of the silkworm diseases|journal=History and Philosophy of the Life Sciences|year=2000|volume=22|issue=1|pages=3–28|pmid=11258099}}</ref><ref name="manchester-2001">{{cite journal |author=Manchester KL |title=Antoine Béchamp: pere de la biologie. Oui ou non? |journal=Endeavour |volume=25 |issue=2 |pages=68–73 |year=2001 |pmid=11484677 |doi= 10.1016/S0160-9327(00)01361-2}}</ref>

However, Béchamp was on the losing side, as the ''[[BMJ]]'' obituary remarked: His name was "associated with bygone controversies as to priority which it would be unprofitable to recall".<ref>{{cite journal|author1=Anonymous|title=Obituary: Professor Bechamp|journal=The British Medical Journal|year=1908|volume=1|issue=2471|page=1150|doi=10.1136/bmj.1.2471.1150-b|pmc=2436492}}</ref> Béchamp proposed the incorrect theory of [[microzyme]]s. According to K. L. Manchester, [[anti-vivisectionist]]s and proponents of [[alternative medicine]] promoted Béchamp and microzymes, unjustifiably claiming that Pasteur plagiarized Béchamp.<ref name=manchester2007 />

Pasteur thought that [[succinic acid]] inverted sucrose. In 1860, [[Marcellin Berthelot]] isolated [[invertase]] and showed that succinic acid did not invert sucrose.<ref name=Barnett /> Pasteur believed that fermentation was only due to living cells. He and Berthelot engaged in a long argument subject of vitalism, in which Berthelot was vehemently opposed to any idea of vitalism.<ref>{{cite book
| last = Friedmann
| first = H C
| chapter = From Friedrich Wöhler's urine to Eduard Buchner's alcohol
| pages = 67–122
| title = New Beer in an Old Bottle: Eduard Buchner and the Growth of Biochemical Knowledge
| editor-last = Cornish-Bowden
| editor-first = A
| date = 1997
| publisher = Universitat de València, Valencia, Spain
| isbn = 84-370-3328-4
}}</ref> [[Hans Ernst August Buchner|Hans Buchner]] discovered that [[zymase]] (not an enzyme, but a mixture of enzymes) catalyzed fermentation, showing that fermentation was catalyzed by enzymes within cells.<ref>{{cite book|last1=Windelspecht|first1=Michael|title=Groundbreaking Scientific Experiments, Inventions, and Discoveries of the 19th Century|year=2003|publisher=Greenwood Publishing Group|location=Westport|isbn=978-0-313-31969-3|page=100|url=https://books.google.com/books?id=hX1jPbJVSu4C}}</ref> [[Eduard Buchner]] also discovered that fermentation could take place outside living cells.<ref>{{cite book|editor1-last=Dworkin|editor1-first=Martin|editor2-last=Falkow|editor2-first=Stanley|editor3-last=Rosenberg|editor3-first=Eugene|editor4-last=Schleifer|editor4-first=Karl-Heinz|editor5-last=Stackebrandt|editor5-first=Erko|title=The Prokaryotes: Vol. 1: Symbiotic Associations, Biotechnology, Applied Microbiology|date=2006|publisher=Springer|isbn=978-0-387-25476-0|pages=285–286|url=https://books.google.com/books?id=hqh43LFTGBQC&pg=PA285}}</ref>

=== Anthrax vaccine ===

Pasteur publicly claimed his success in developing the anthrax vaccine in 1881.<ref name=trueman /> However, his admirer-turned-rival [[Jean Joseph Henri Toussaint|Henry Toussaint]] was the one who developed the first vaccine. Toussaint isolated the bacteria that caused chicken cholera (later named ''[[Pasteurella]]'' in honour of Pasteur) in 1879 and gave samples to Pasteur who used them for his own works.<ref>{{cite book|last1=Swabe|first1=Joanna|title=Animals, Disease and Human Society: Human-animal Relations and the Rise of Veterinary Medicine|date=2002|publisher=Routledge|isbn=978-1-134-67540-1|page=83|url=https://books.google.com/books?id=4WWGAgAAQBAJ&pg=PA83}}</ref> On 12 July 1880, Toussaint presented his successful result to the French Academy of Sciences, using an attenuated vaccine against anthrax in dogs and sheep.<ref>{{cite book|last=Jones|first=Susan D.|title=Death in a Small Package: A Short History of Anthrax|year=2010|publisher=JHU Press|isbn=978-1-4214-0252-9|page=69|url=https://books.google.com/books?id=mK72X-XkIKgC}}</ref> Pasteur on grounds of jealousy contested the discovery by publicly displaying his vaccination method at Pouilly-le-Fort on 5 May 1881.<ref name=Chevallier-Jussiau /> Pasteur then gave a misleading account of the preparation of the anthrax vaccine used in the experiment. He claimed that he made a "live vaccine", but used potassium dichromate<ref name=Geison1995 /> to inactivate anthrax spores, a method similar to Toussaint's. The promotional experiment was a success and helped Pasteur sell his products, getting the benefits and glory.<ref name="Giese" /><ref name=Chevallier-Jussiau>{{cite journal|last=Chevallier-Jussiau|first=N|title=[Henry Toussaint and Louis Pasteur. Rivalry over a vaccine]|journal=Histoire des Sciences Médicales|year=2010|volume=44|issue=1|pages=55–64|pmid=20527335|url=http://www.biusante.parisdescartes.fr/sfhm/hsm/HSMx2010x044x001/HSMx2010x044x001x0055.pdf|access-date=14 March 2017|archive-date=25 February 2021|archive-url=https://web.archive.org/web/20210225013513/https://www.biusante.parisdescartes.fr/sfhm/hsm/HSMx2010x044x001/HSMx2010x044x001x0055.pdf|url-status=live}}</ref><ref>{{cite journal|last=Williams|first=E|title=The forgotten giants behind Louis Pasteur: contributions by the veterinarians Toussaint and Galtier|journal=Veterinary Heritage|year=2010|volume=33|issue=2|pages=33–39|pmid=21466009}}</ref><ref>{{cite book|last=Flower|first=Darren R.|title=Bioinformatics for Vaccinology|year=2008|publisher=John Wiley & Sons|location=Chichester|isbn=978-0-470-69982-9|page=31|url=https://books.google.com/books?id=Rg6-T_1-LWkC}}</ref>

=== Experimental ethics ===

Pasteur's experiments are often cited as against [[medical ethics]], especially on his vaccination of Meister. He did not have any experience in medical practice, and more importantly, lacked a [[medical license]]. This is often cited as a serious threat to his professional and personal reputation.<ref>{{cite journal|last1=Geison|first1=Gerald L.|title=Pasteur, Roux, and Rabies: Scientific Clinical Mentalities|journal=Journal of the History of Medicine and Allied Sciences|year=1990|volume=45|issue=3|pages=341–365|doi=10.1093/jhmas/45.3.341|pmid=2212608}}</ref><ref>{{cite book|last1=Forster|first1=Patrice Debré; translated by Elborg|title=Louis Pasteur|year=2000|publisher=Johns Hopkins University Press|location=Baltimore|isbn=978-0-8018-6529-9|pages=455–456|edition=Johns Hopkins pbk.|url=https://books.google.com/books?id=RzOcl-FLw30C}}</ref> His closest partner [[Émile Roux]], who had medical qualifications, refused to participate in the [[clinical trial]], likely because he considered it unjust.<ref name=Jackson>{{cite book|editor-last=Jackson|editor-first=Alan C.|title=Rabies: Scientific Basis of the Disease and Its Management|year=2013|publisher=Academic Press|location=Amsterdam|isbn=978-0-12-397230-9|pages=3–6|url=https://books.google.com/books?id=e1UFMYVHCboC&pg=PA3|edition=3rd}}</ref> However, Pasteur executed vaccination of the boy under the close watch of practising physicians [[Jacques-Joseph Grancher]], head of the Paris Children's Hospital's paediatric clinic, and [[Alfred Vulpian]], a member of the Commission on Rabies. He was not allowed to hold the syringe, although the inoculations were entirely under his supervision.<ref name=Wasik>{{cite book|last=Wasik|first=Bill|title=Rabid: A Cultural History of the World's Most Diabolical Virus|year=2013|publisher=Penguin Books|location=New York|isbn=978-1-101-58374-6|url=https://books.google.com/books?id=i8j30cXPKj8C&q=louis+pasteur+medical+license&pg=PT102|author2=Murphy, Monica}}</ref> It was Grancher who was responsible for the injections, and he defended Pasteur before the [[Académie de Médecine|French National Academy of Medicine]] in the issue.<ref>{{cite journal|last=Gelfand|first=T|title=11 January 1887, the day medicine changed: Joseph Grancher's defense of Pasteur's treatment for rabies|journal=Bulletin of the History of Medicine|year=2002|volume=76|issue=4|pages=698–718|pmid=12446976|doi=10.1353/bhm.2002.0176|s2cid=33145788}}</ref>

Pasteur has also been criticized for keeping secrecy of his procedure and not giving proper pre-clinical trials on animals.<ref name=Ligon /> Pasteur stated that he kept his procedure secret in order to control its quality. He later disclosed his procedures to a small group of scientists. Pasteur wrote that he had successfully vaccinated 50 rabid dogs before using it on Meister.<ref>{{cite book|last=Murphy|first=Timothy F.|title=Case Studies in Biomedical Research Ethics|year=2004|publisher=MIT Press|location=Cambridge|isbn=978-0-262-63286-7|page=[https://archive.org/details/casestudiesinbio0000murp/page/83 83]|url=https://archive.org/details/casestudiesinbio0000murp|url-access=registration}}</ref><ref>{{cite journal|last=Geison|first=GL|title=Pasteur's work on rabies: reexamining the ethical issues|journal=The Hastings Center Report|year=1978|volume=8|issue=2|pages=26–33|pmid=348641|doi=10.2307/3560403|jstor=3560403}}</ref><ref>{{cite journal|last=Hoenig|first=Leonard J.|title=Triumph and controversy. Pasteur's preventive treatment of rabies as reported in JAMA|journal=Archives of Neurology|year=1986|volume=43|issue=4|pages=397–399|doi=10.1001/archneur.1986.00520040075024|pmid=3513741}}</ref> According to Geison, Pasteur's laboratory notebooks show that he had vaccinated only 11 dogs.<ref name=Ligon />

== Awards and honours ==
Pasteur was awarded 1,500 [[franc]]s in 1853 by the Pharmaceutical Society for the synthesis of [[racemic acid]].<ref>{{cite book|last1=Debré|first1=Patrice|translator-last=Forster|translator-first=Elborg|title=Louis Pasteur|date=2000|publisher=JHU Press|location=Baltimore|isbn=978-0-8018-6529-9|pages=503}}</ref> In 1856 the [[Royal Society]] of London presented him the [[Rumford Medal]] for his discovery of the nature of racemic acid and its relations to polarized light,<ref>{{cite journal|last=Lord Wrottesley|title=[Address Delivered before the Royal Society]|journal=Proceedings of the Royal Society of London|year=1856|volume=8|pages=254–257|doi=10.1098/rspl.1856.0067|s2cid=186212787|url=https://zenodo.org/record/1432037|doi-access=free|access-date=8 September 2019|archive-date=8 March 2021|archive-url=https://web.archive.org/web/20210308233748/https://zenodo.org/record/1432037|url-status=live}}</ref> and the [[Copley Medal]] in 1874 for his work on fermentation.<ref>{{cite journal|title=Anniversary Meeting|journal=Proceedings of the Royal Society of London|year=1874|volume=23|issue=156–163|pages=68–70|doi=10.1098/rspl.1874.0007|s2cid=186209582}}</ref> He was elected a [[List of Fellows of the Royal Society elected in 1869|Foreign Member of the Royal Society (ForMemRS) in 1869]].<ref name=formemrs>{{cite web|archive-url=https://web.archive.org/web/20150316060617/https://royalsociety.org/about-us/fellowship/fellows/|archive-date=16 March 2015|url=https://royalsociety.org/about-us/fellowship/fellows/|publisher=[[Royal Society]]|location=London|title=Fellows of the Royal Society}}</ref>

The [[French Academy of Sciences]] awarded Pasteur the 1859 [[Montyon Prizes|Montyon Prize]] for experimental physiology in 1860,<ref name="Debré & Patrice pp. 505-7" /> and the Jecker Prize in 1861 and the Alhumbert Prize in 1862 for his experimental refutation of spontaneous generation.<ref name="porter" /><ref>{{cite journal|last1=Manchester|first1=Keith|title=Exploding the Pasteurian legend|journal=Endeavour|year=2001|volume=25|issue=4|pages=148–152|doi=10.1016/S0160-9327(00)01389-2 |pmid=11590017}} Also {{cite journal | pmid=11590017 | volume=26 | issue=10 | title=Exploding the Pasteurian legend | year=2001 | journal=Trends Biochem. Sci. | pages=632–636 | author=Manchester K | doi=10.1016/s0968-0004(01)01909-0}}</ref> Though he lost elections in 1857 and 1861 for membership to the French Academy of Sciences, he won the 1862 election for membership to the mineralogy section.<ref>{{cite book|last1=Keim|first1=Albert|last2=Lumet|first2=Louis|title=Louis Pasteur|date=1914|publisher=Frederick A. Stokes Company|pages=50–51, 69|url=https://archive.org/stream/louispasteur00keim#page/50/mode/2up}}</ref> He was elected to permanent secretary of the physical science section of the academy in 1887 and held the position until 1889.<ref>{{cite web|title=Biographie|url=http://www.academie-sciences.fr/archivage_site/fondations/lp_bio.htm|website=Maison de Louis Pasteur|language=fr|access-date=13 February 2017|archive-date=21 April 2021|archive-url=https://web.archive.org/web/20210421052206/https://www.academie-sciences.fr/archivage_site/fondations/lp_bio.htm|url-status=live}}</ref>

In 1873, Pasteur was elected to the [[Académie Nationale de Médecine]]<ref>{{cite book|last1=Vallery-Radot|first1=René|translator-last=Devonshire|translator-first=R. L.|title=The Life of Pasteur|date=1919|publisher=Constable & Company|location=London|page=225|url=https://archive.org/stream/in.ernet.dli.2015.173907/2015.173907.The-Life-Of-Pasteur#page/n245/mode/2up}}</ref> and was made the commander in the Brazilian [[Order of the Rose]].<ref>{{cite book|last1=Debré|first1=Patrice|translator-last=Forster|translator-first=Elborg|title=Louis Pasteur|date=2000|publisher=JHU Press|location=Baltimore|isbn=978-0-8018-6529-9|pages=508}}</ref> In 1881 he was elected to a seat at the [[Académie française]] left vacant by [[Émile Littré]].<ref>{{cite book|last1=Debré|first1=Patrice|translator-last=Forster|translator-first=Elborg|title=Louis Pasteur|date=2000|publisher=JHU Press|location=Baltimore|isbn=978-0-8018-6529-9|pages=509}}</ref> Pasteur received the [[Albert Medal (Royal Society of Arts)|Albert Medal]] from the [[Royal Society of Arts]] in 1882.<ref name="Frankland & Frankland p. 211">{{cite book|last1=Frankland|first1=Percy|title=Pasteur|date=1901|publisher=Cassell and Company|page=211|url=https://archive.org/stream/pasteur00frangoog#page/n213/mode/2up}}</ref> In 1883 he became foreign member of the [[Royal Netherlands Academy of Arts and Sciences]].<ref>{{cite web |url=http://www.dwc.knaw.nl/biografie/pmknaw/?pagetype=authorDetail&aId=PE00002251 |title=Louis Pasteur (1822–1895) |publisher=Royal Netherlands Academy of Arts and Sciences |access-date=19 July 2015 |archive-date=21 July 2015 |archive-url=https://web.archive.org/web/20150721212243/http://www.dwc.knaw.nl/biografie/pmknaw/?pagetype=authorDetail&aId=PE00002251 |url-status=live }}</ref> In 1885, he was elected as a member to the [[American Philosophical Society]].<ref>{{Cite web|title=APS Member History|url=https://search.amphilsoc.org/memhist/search?creator=&title=&subject=&subdiv=&mem=&year=1885&year-max=&dead=&keyword=&smode=advanced|access-date=21 May 2021|website=search.amphilsoc.org|archive-date=21 May 2021|archive-url=https://web.archive.org/web/20210521154246/https://search.amphilsoc.org/memhist/search?creator=&title=&subject=&subdiv=&mem=&year=1885&year-max=&dead=&keyword=&smode=advanced|url-status=live}}</ref> On 8 June 1886, the Ottoman Sultan [[Abdul Hamid II]] awarded Pasteur with the [[Order of the Medjidie]] (I Class) and 10000 Ottoman liras.<ref>Sevan Nişanyan: ''Yanlış Cumhuriyet'' İstanbul: Kırmızı Yayınları 2009, S.&nbsp;263.</ref> He was awarded the [[Cameron Prize for Therapeutics of the University of Edinburgh]] in 1889.<ref>{{Cite book|last=Lutzker|first=Edythe|title=Clio Medica : Acta Academiae Internationalis Historiae Medicinae, Vol. 13 |date=1 January 1978|chapter=Cameron Prizewinner: Waldemar M. Haffkine, C. I. E.|chapter-url=https://brill.com/view/book/edcoll/9789004418257/B9789004418257_s030.xml|series=Clio Medica: Acta Academiae Internationalis Historiae Medicinae|volume=13|issue=3–4|language=en|pages=269–276|doi=10.1163/9789004418257_030|pmid=89932|isbn=978-9004418257|access-date=12 May 2020|archive-date=24 September 2021|archive-url=https://web.archive.org/web/20210924070039/https://brill.com/view/book/edcoll/9789004418257/B9789004418257_s030.xml|url-status=live}}</ref> Pasteur won the [[Leeuwenhoek Medal]] from the [[Royal Netherlands Academy of Arts and Sciences]] for his contributions to [[microbiology]] in 1895.<ref>{{cite web|title=Leeuwenhoek Medal|url=https://www.knaw.nl/en/awards/laureates/leeuwenhoekmedaille|publisher=Royal Netherlands Academy of Arts and Sciences|access-date=7 February 2017|archive-date=3 March 2016|archive-url=https://web.archive.org/web/20160303201924/https://www.knaw.nl/en/awards/laureates/leeuwenhoekmedaille|url-status=dead}}</ref>

Pasteur was made a Chevalier of the [[Legion of Honour]] in 1853, promoted to Officer in 1863, to Commander in 1868, to Grand Officer in 1878 and made a Grand Cross of the Legion of Honor in 1881.<ref>{{cite web|title=Louis Pasteur|url=http://www.legiondhonneur.fr/fr/decores/louis-pasteur/131|website=Grande chancellerie de la Légion d'honneur|access-date=7 February 2017|language=fr|archive-date=7 February 2017|archive-url=https://web.archive.org/web/20170207192613/http://www.legiondhonneur.fr/fr/decores/louis-pasteur/131|url-status=live}}</ref><ref name="Frankland & Frankland p. 211" />

[[File:Danang Vietnam rue Pasteur2.jpg|thumb|Pasteur Street (''Đường Pasteur'') in [[Da Nang]], Vietnam]]

=== Legacy ===
[[File:Vulitsya Pastera.JPG|thumb|left|alt=Pasteur's street in Odesa.|Vulitsya Pastera or Pasteur Street in [[Odesa]], [[Ukraine]]]]
{{Main|List of things named after Louis Pasteur}}

In many localities worldwide, streets are named in his honor. For example, in the US: [[Palo Alto, California|Palo Alto]] and [[Irvine, California]], Boston and Polk, Florida, adjacent to the [[University of Texas Health Science Center at San Antonio]]; Jonquière, Québec; San Salvador de Jujuy and Buenos Aires ([[Argentina]]), [[Great Yarmouth]] in Norfolk, in the United Kingdom, Jericho and Wulguru in Queensland, Australia; [[Phnom Penh]] in Cambodia; [[Ho Chi Minh City]] and [[Da Nang]], Vietnam; Batna in [[Algeria]]; [[Bandung]] in Indonesia, [[Tehran]] in Iran, near the central campus of the [[Warsaw University]] in [[Warsaw]], Poland; adjacent to the [[Odesa State Medical University]] in [[Odesa]], Ukraine; [[Milan]] in Italy and [[Bucharest]], [[Cluj-Napoca]] and [[Timișoara]] in Romania. The Avenue Pasteur in Saigon, Vietnam, is one of the few streets in that city to retain its French name. ''Avenue Louis Pasteur'' in the [[Longwood Medical and Academic Area]] in [[Boston]] was named in his honor in the French manner with "Avenue" preceding the name of the dedicatee.<ref>{{Cite web|url=http://www.pasteurfoundation.org/MAHarvardAvePasteur.shtml|archiveurl=https://web.archive.org/web/20101014093352/http://www.pasteurfoundation.org/MAHarvardAvePasteur.shtml|url-status=dead|title=Remembrance of Things Pasteur|archivedate=14 October 2010}}</ref>

Both the Institut Pasteur and [[Université Louis Pasteur]] were named after Pasteur. The schools [[Lycée Pasteur (Neuilly-sur-Seine)|Lycée Pasteur]] in [[Neuilly-sur-Seine]], France, and Lycée Louis Pasteur in [[Calgary|Calgary, Alberta]], Canada, are named after him. In South Africa, the Louis Pasteur Private Hospital in [[Pretoria]], and Life Louis Pasteur Private Hospital, [[Bloemfontein]], are named after him. Louis Pasteur University Hospital in [[Košice]], [[Slovakia]] is also named after Pasteur.

[[File:UNLP Košice, Poliklinika (1).JPG|thumb|right|Louis Pasteur University Hospital, [[Košice]], [[Slovakia]] ]]

A statue of Pasteur is erected at [[San Rafael High School]] in [[San Rafael, California]]. A bronze bust of him resides on the French Campus of [[Kaiser Permanente]]'s San Francisco Medical Center in [[San Francisco]]. The sculpture was designed by Harriet G. Moore and cast in 1984 by Artworks Foundry.<ref name=SOS>{{cite web|title=Louis Pasteur, (sculpture)|url=http://siris-artinventories.si.edu/ipac20/ipac.jsp?profile=all&source=~!siartinventories&uri=full=3100001~!310287~!0#focus|work=Save Outdoor Sculpture!|publisher=[[Smithsonian American Art Museum]]|access-date=12 May 2012|archive-date=29 September 2015|archive-url=https://web.archive.org/web/20150929001947/http://siris-artinventories.si.edu/ipac20/ipac.jsp?&profile=all&source=~!siartinventories&uri=full=3100001~!310287~!0#focus|url-status=live}}</ref>

The [[UNESCO/Institut Pasteur Medal]] was created on the centenary of Pasteur's death, and is given every two years in his name, "in recognition of outstanding research contributing to a beneficial impact on human health".<ref name="unesco-2005">{{cite web|url=http://portal.unesco.org/en/ev.php-URL_ID%3D26770%26URL_DO%3DDO_TOPIC%26URL_SECTION%3D201.html|title=Louis Pasteur (1822–1895)|publisher=UNESCO|access-date=21 January 2018|archive-date=26 May 2017|archive-url=https://web.archive.org/web/20170526113110/http://portal.unesco.org/en/ev.php-URL_ID%3D26770%26URL_DO%3DDO_TOPIC%26URL_SECTION%3D201.html|url-status=live}}</ref>

The French Academician [[Henri Mondor]] stated: "''Louis Pasteur was neither a physician nor a surgeon, but no one has done as much for medicine and surgery as he has''."<ref name="Mondor">{{cite web |title=Henri Mondor, Pasteur |url=https://encyclopedie_universelle.fracademic.com/9931/HYGI%C3%88NE |access-date=31 October 2021 |archive-date=5 June 2020 |archive-url=https://web.archive.org/web/20200605200937/https://encyclopedie_universelle.fracademic.com/9931/HYGI%C3%88NE |url-status=live }}</ref>

=== Pasteur Institute ===
{{Main|Pasteur Institute}}
After developing the rabies vaccine, Pasteur proposed an institute for the vaccine.<ref>{{cite book|last1=Vallery-Radot|first1=René|translator-last=Devonshire|translator-first=R. L.|title=The Life of Pasteur|date=1919|publisher=Constable & Company|location=London|page=428|url=https://archive.org/stream/in.ernet.dli.2015.173907/2015.173907.The-Life-Of-Pasteur#page/n447/mode/2up}}</ref> In 1887, fundraising for the Pasteur Institute began, with donations from many countries. The official statute was registered in 1887, stating that the institute's purposes were "the treatment of rabies according to the method developed by M. Pasteur" and "the study of virulent and contagious diseases".<ref name=Wasik /> The institute was inaugurated on 14 November 1888.<ref name=Wasik /> He brought together scientists with various specialties. The first five departments were directed by two graduates of the ''[[École Normale Supérieure]]'': [[Émile Duclaux]] (general [[microbiology]] research) and [[Charles Chamberland]] (microbe research applied to [[hygiene]]), as well as a biologist, [[Élie Metchnikoff]] (morphological microbe research) and two [[physician]]s, [[Jacques-Joseph Grancher]] ([[rabies]]) and [[Émile Roux]] (technical microbe research). One year after the inauguration of the institute, Roux set up the first course of microbiology ever taught in the world, then entitled ''Cours de Microbie Technique'' (Course of microbe research techniques). Since 1891 the Pasteur Institute had been extended to different countries, and currently there are 32 institutes in 29 countries in various parts of the world.<ref>{{cite web|title= Institut Pasteur International Network|url= http://www.pasteur-international.org/ip/easysite/pasteur-international-en/institut-pasteur-international-network/the-network|work= pasteur-international.org|access-date= 3 July 2013|archive-date= 6 June 2014|archive-url= https://web.archive.org/web/20140606153949/http://www.pasteur-international.org/ip/easysite/pasteur-international-en/institut-pasteur-international-network/the-network|url-status= live}}</ref>

== Personal life ==
[[File:Louis Pasteur en 1857.jpg|alt=Louis Pasteur in 1857|thumb|right|Pasteur in 1857]]
Pasteur married [[Marie Pasteur]] (née Laurent) in 1849.  She was the daughter of the rector of the University of Strasbourg, and was Pasteur's scientific assistant.  They had five children together, three of whom died as children.<ref>{{Cite book|last1=Ogilvie|first1=Marilyn Bailey|url=https://books.google.com/books?id=LTSYePZvSXYC&q=Marie+Pasteur+assistant&pg=PA986|title=The Biographical Dictionary of Women in Science: L-Z|last2=Harvey|first2=Joy Dorothy|date=2000|publisher=Taylor & Francis|isbn=978-0-415-92040-7|language=en}}</ref> Their eldest daughter, Jeanne, was born in 1850. She died from [[typhoid fever]], aged 9, whilst at the boarding school [[Arbois]] in 1859. In 1865, 2-year-old Camille died of a liver tumour. Shortly after they decided to bring Cécile home from boarding school, but she too died of typhoid fever on 23 May 1866 at the age of 12. Only Jean Baptiste (b. 1851) and Marie Louise (b. 1858) survived to adulthood. Jean Baptiste would be a soldier in the [[Franco-Prussian War]] between [[France]] and [[Prussia]].<ref>{{Cite web |date=10 November 2016 |title=History |url=https://www.pasteur.fr/en/institut-pasteur/history |access-date=19 June 2022 |website=Institut Pasteur |language=en-gb |archive-date=10 March 2021 |archive-url=https://web.archive.org/web/20210310084851/https://www.pasteur.fr/en/institut-pasteur/history |url-status=live }}</ref>

=== Faith and spirituality ===
His grandson, [[Louis Pasteur Vallery-Radot]], wrote that Pasteur had kept from his Catholic background only a spiritualism without religious practice.<ref>Pasteur Vallery-Radot, Letter to Paul Dupuy, 1939, quoted by Hilaire Cuny, ''Pasteur et le mystère de la vie'', Paris, Seghers, 1963, pp. 53–54. Patrice Pinet, ''Pasteur et la philosophie'', Paris, 2005, pp. 134–135, quotes analogous assertions of Pasteur Vallery-Radot, with references to Pasteur Vallery-Radot, ''Pasteur inconnu'', p. 232, and André George, ''Pasteur'', Paris, 1958, p. 187. According to Maurice Vallery-Radot (''Pasteur'', 1994, p. 378), the false quotation appeared for the first time in the ''Semaine religieuse&nbsp;... du diocèse de Versailles'', 6 October 1895, p. 153, shortly after the death of Pasteur.</ref> However, Catholic observers often said that Pasteur remained an ardent Christian throughout his whole life, and his son-in-law wrote, in a biography of him:
{{blockquote|Absolute faith in God and in Eternity, and a conviction that the power for good given to us in this world will be continued beyond it, were feelings which pervaded his whole life; the virtues of the gospel had ever been present to him. Full of respect for the form of religion which had been that of his forefathers, he came simply to it and naturally for spiritual help in these last weeks of his life.<ref>(Vallery-Radot 1911, vol. 2, p. 240)</ref>}}

The ''Literary Digest'' of 18 October 1902 gives this statement from Pasteur that he prayed while he worked:<ref>{{Cite book |url=http://archive.org/details/sim_literary-digest_1902-10-18_25_16 |title=The Literary Digest 1902-10-18 |date=1902-10-18 |others=[[Internet Archive]] |volume=25 |pages=420 |language=English}}</ref>
{{blockquote|Posterity will one day laugh at the foolishness of modern materialistic philosophers. The more I study nature, the more I stand amazed at the work of the Creator. I pray while I am engaged at my work in the laboratory.}}

Maurice Vallery-Radot, grandson of the brother of the son-in-law of Pasteur and outspoken Catholic, also holds that Pasteur fundamentally remained Catholic.<ref>{{Cite book| last = Vallery-Radot| first = Maurice | title = Pasteur| publisher = Perrin| year = 1994| location = Paris| pages = 377–407}}</ref> According to both Pasteur Vallery-Radot and Maurice Vallery-Radot, the following well-known [[quotation]] attributed to Pasteur is apocryphal:<ref>Pasteur Vallery-Radot, Letter to Paul Dupuy, 1939, quoted by Hilaire Cuny, ''Pasteur et le mystère de la vie'', Paris, Seghers, 1963, pp. 53–54.</ref> "The more I know, the more nearly is my faith that of the Breton peasant. Could I but know all I would have the faith of a Breton peasant's wife".<ref name="catholic intro" /> According to Maurice Vallery-Radot,<ref>''Pasteur'', 1994, p. 378.</ref> the false quotation appeared for the first time shortly after the death of Pasteur.<ref>In Pasteur's ''Semaine religieuse&nbsp;... du diocèse de Versailles'', 6 October 1895, p. 153.</ref> However, despite his belief in God, it has been said that his views were that of a freethinker rather than a Catholic, a spiritual more than a religious man.<ref>{{cite book|title=A Biographical Dictionary of Ancient, Medieval, and Modern Freethinkers|year=1945|publisher=Haldeman-Julius Publications|url=http://www.infidels.org/library/historical/joseph_mccabe/dictionary.html|author=Joseph McCabe|access-date=11 August 2012|quote=The anonymous Catholic author quotes as his authority the standard biography by Vallery-Radot, yet this describes Pasteur as a freethinker; and this is confirmed in the preface to the English translation by Sir W. Osler, who knew Pasteur personally. Vallery-Radot was himself a Catholic yet admits that Pasteur believed only in "an Infinite" and "hoped" for a future life. Pasteur publicly stated this himself in his Academy speech in 1822 (in V.R.). He said: "The idea of God is a form of the idea of the Infinite whether it is called Brahma, Allah, Jehova, or Jesus." The biographer says that in his last days he turned to the Church but the only "evidence" he gives is that he liked to read the life of St. Vincent de Paul, and he admits that he did not receive the sacraments at death. Relatives put rosary beads in his hands, and the Catholic Encyclopedia claims him as a Catholic in virtue of the fact and of an anonymous and inconclusive statement about him. Wheeler says in his Dictionary of Freethinkers that in his prime Pasteur was Vice-President of the British Secular (Atheist) Union; and Wheeler was the chief Secularist writer of the time. The evidence is overwhelming. Yet the Catholic scientist Sir Bertram Windle assures his readers that "no person who knows anything about him can doubt the sincerity of his attachment to the Catholic Church," and all Catholic writers use much the same scandalous language.|archive-date=13 January 2013|archive-url=https://web.archive.org/web/20130113004909/http://www.infidels.org/library/historical/joseph_mccabe/dictionary.html|url-status=live}}</ref><ref>{{cite book|title=Louis Pasteur|year=2000|publisher=JHU Press|isbn=978-0-8018-6529-9|author=Patrice Debré|page=176|quote=Does this mean that Pasteur was bound to a religious ideal? His attitude was that of a believer, not of a sectarian. One of his most brilliant disciples, Elie Metchnikoff, was to attest that he spoke of religion only in general terms. In fact, Pasteur evaded the question by claiming quite simply that religion has no more place in science than science has in religion.&nbsp;... A biologist more than a chemist, a spiritual more than a religious man, Pasteur was held back only by the lack of more powerful technical means and therefore had to limit himself to identifying germs and explaining their generation.}}</ref> He was also against mixing science with religion.<ref>{{cite book|last=Debré|first=Patrice|translator-last=Forster|translator-first=Elborg|title=Louis Pasteur|date=2000|publisher=JHU Press|isbn=978-0-8018-6529-9|page=368|url=https://books.google.com/books?id=RzOcl-FLw30C&pg=PA368|quote=Pasteur advocated separation of science and religion: "In each one of us there are two men, the scientist and the man of faith or of doubt. These two spheres are separate, and woe to those who want to make them encroach upon one another in the present state of our knowledge!"}}</ref><ref>{{cite book|title=Louis Pasteur|year=2000|publisher=JHU Press|isbn=978-0-8018-6529-9|author=Patrice Debré|page=176}}</ref>

=== Death ===
In 1868, Pasteur suffered a<!-- !  check for tone !--> severe brain stroke that paralysed the left side of his body, but he recovered.<ref>{{cite book|last1=Vallery-Radot|first1=René|translator-last=Devonshire|translator-first=R. L.|title=The Life of Pasteur|date=1919|publisher=Constable & Company|location=London|pages=159–168|url=https://archive.org/stream/in.ernet.dli.2015.173907/2015.173907.The-Life-Of-Pasteur#page/n179/mode/2up}}</ref> A [[stroke]] or [[uremia]] in 1894 severely impaired his health.<ref>{{cite book|last1=Debré|first1=Patrice|translator-last=Forster|translator-first=Elborg|title=Louis Pasteur|date=2000|publisher=JHU Press|location=Baltimore|isbn=978-0-8018-6529-9|pages=512}}</ref><ref>{{cite book|last1=Keim|first1=Albert|last2=Lumet|first2=Louis|title=Louis Pasteur|date=1914|publisher=Frederick A. Stokes Company|page=206|url=https://archive.org/stream/louispasteur00keim#page/206/mode/2up}}</ref><ref>{{cite book|last1=Vallery-Radot|first1=René|translator-last=Devonshire|translator-first=R. L.|title=The Life of Pasteur|date=1919|publisher=Constable & Company|location=London|page=458|url=https://archive.org/stream/in.ernet.dli.2015.173907/2015.173907.The-Life-Of-Pasteur#page/n477/mode/2up}}</ref> Failing to fully recover, he died on 28 September 1895, near Paris.<ref name="cohn" /> He was given a [[state funeral]] and was buried in the [[Notre Dame de Paris|Cathedral of Notre Dame]], but his remains were reinterred in the Pasteur Institute in Paris,<ref>{{cite book|last1=Frankland|first1=Percy|title=Pasteur|date=1901|publisher=Cassell and Company|pages=217–219|url=https://archive.org/stream/pasteur00frangoog#page/n219/mode/2up}}</ref> in a vault covered in depictions of his accomplishments in [[Mosaic#Byzantine mosaics|Byzantine mosaics]].<ref>{{Cite journal| last = Campbell| first = D M| title = The Pasteur Institute of Paris| journal = American Journal of Veterinary Medicine| volume = 10| issue = 1| pages = 29–31| date = January 1915| url = https://books.google.com/books?id=u8FUAAAAMAAJ| access-date = 8 February 2010}}</ref>

== Publications ==
Pasteur's principal published works are:<ref name="catholic intro" />
{| class="wikitable"
|-
! French Title!! Year!! English Title
|-
|''Études sur le Vin''|| 1866|| ''Studies on Wine''
|-
| ''Études sur le Vinaigre''|| 1868|| ''Studies on Vinegar''
|-
|  ''Études sur la Maladie des Vers à Soie'' (2 volumes)|| 1870|| ''Studies on Silk Worm Disease''
|-
| ''Quelques Réflexions sur la Science en France'' || 1871||'' Some Reflections on Science in France''
|-
| ''Études sur la Bière'' || 1876|| ''Studies on Beer''
|-
| ''Les Microbes organisés, leur rôle dans la Fermentation, la Putréfaction et la Contagion''|| 1878||'' Microbes organized, their role in fermentation, putrefaction and the Contagion''
|-
| ''Discours de Réception de M.L. Pasteur à l'Académie française'' || 1882|| ''Speech by Mr L. Pasteur on reception to the Académie française''
|-
| ''Traitement de la Rage''|| 1886|| ''Treatment of Rabies''
|}
{{Clear}}
{{botanist|Pasteur}}

== See also ==
{{portal|Biography}}
* [[Infection control]]
* [[Infectious disease]]
* [[Pasteur Institute]]
* [[Pasteurization]]
* ''[[The Story of Louis Pasteur]]'' (a 1936 biographical film)
* [[List of things named after Louis Pasteur]]
* [[Statue of Louis Pasteur, Mexico City]]

== References ==
{{Reflist}}

== Further reading ==
{{Refbegin}}
* {{cite book |last=Benz |first=Francis E. |title=Pasteur, Knight of the Laboratory |url=https://www.fadedpage.com/showbook.php?pid=20230210 |year=1938 |publisher=Dodd, Mead & Company |location=New York|access-date=12 February 2023 |archive-date=12 February 2023 |archive-url=https://web.archive.org/web/20230212030957/https://www.fadedpage.com/showbook.php?pid=20230210 |url-status=live }}
* {{cite book |last=Debré |first=P. |author2=E. Forster |title=Louis Pasteur |url=https://archive.org/details/louispasteur0000debr |url-access=registration |year=1998 |publisher=Johns Hopkins University Press |location=Baltimore |isbn=978-0-8018-5808-6 }}
* {{cite book |last=Duclaux |first=E.Translated by Erwin F. Smith and Florence Hedges |title=Louis Pasteur: The History of a Mind |url=https://archive.org/details/pasteurhistorya00duclgoog |year=1920 |publisher=W.B. Saunders Company |location=Philadelphia |asin=B001RV90WA }}
* {{cite book |last=Geison |first=Gerald L. |author-link=Gerald L. Geison |title=The Private Science of Louis Pasteur |url=https://archive.org/details/privatescienceof0000geis_s1q6 |url-access=registration |year=1995 |publisher=Princeton University Press |location=Princeton|isbn=978-0-691-03442-3 }}
* Cédric Grimoult, ''Pasteur: Le mythe au coeur de l'action (ou le combattant)'', Paris, Ellipses, coll. "Biographies et mythes historiques", 2021, 332 p.
* {{cite book|last=de Kruif|first=Paul|author-link=Paul de Kruif|date=1926|title=Microbe Hunters|series=Blue Ribbon Books|publisher=Harcourt Brace & Company Inc.|location=New York|url=https://archive.org/details/in.ernet.dli.2015.221187/page/n3/mode/2up|access-date=9 October 2020}}, chapters III (PASTEUR: Microbes are a Menace!) and V (PASTEUR: And the Mad Dog)
* {{cite book |last=Latour |first=Bruno |author-link=Bruno Latour |title=The Pasteurization of France |year=1988 |publisher=Harvard University Press |location=Boston |isbn=978-0-674-65761-8 }}
* Reynolds, Moira Davison. '' How Pasteur Changed History: The Story of Louis Pasteur and the Pasteur Institute'' (1994)
* {{cite book |last=Williams |first=Roger L. |author-link=Roger L. Williams |title=Gaslight and Shadow: The World of Napoleon III, 1851–1870 |url=https://archive.org/details/gaslightandshado006960mbp |year=1957 |publisher=Macmillan Company |location=New York |isbn=978-0-8371-9821-7 }}
{{Refend}}

== External links ==
{{Library resources box|by=yes|onlinebooksby=yes|viaf= 54152415}}
{{Commons}}
{{wikisource author}}
{{Wikiquote}}
{{EB1911 poster|Pasteur, Louis}}
* [https://www.pasteur.fr/en The Institut Pasteur] – Foundation dedicated to the prevention and treatment of diseases through biological research, education and public health activities
* [http://www.pasteurfoundation.org/ The Pasteur Foundation] – A US nonprofit organization dedicated to promoting the mission of the [[Institut Pasteur]] in Paris. Full archive of newsletters available online containing examples of US Tributes to Louis Pasteur.
* [http://biotech.law.lsu.edu/cphl/history/articles/pasteur.htm Pasteur's Papers on the Germ Theory]
* [http://www.pasteurbrewing.com/ The Life and Work of Louis Pasteur], Pasteur Brewing
* [http://pasteur.net/?lang=en The Pasteur Galaxy]
* [http://www.fordham.edu/halsall/mod/1878pasteur-germ.html Germ Theory and Its Applications to Medicine and Surgery, 1878]
* [http://www.accessexcellence.org/RC/AB/BC/Louis_Pasteur.html Louis Pasteur (1822–1895)] profile, AccessExcellence.org
* {{Internet Archive author |sname=Louis Pasteur}}
* {{Librivox author |id=8786}}
* {{PM20 |FID=pe/013276}}
* {{cite book|url= http://gallica.bnf.fr/ark:/12148/bpt6k7356c |title=Pasteur Œuvre tome 1 – Dissymétrie moléculaire |date=1922–1939 |language=fr}}
* {{cite book|url= http://gallica.bnf.fr/ark:/12148/bpt6k7357p |title=Pasteur Œuvre tome 2 – Fermentations et générations dites spontanées |date=1922–1939 |language=fr}}
* [http://math-doc.ujf-grenoble.fr/RBSM/cr-gallica.html ''Comptes rendus de l'Académie des sciences''] {{Webarchive|url=https://web.archive.org/web/20140311021045/http://math-doc.ujf-grenoble.fr/RBSM/cr-gallica.html |date=11 March 2014 }} Articles published by Pasteur {{in lang|fr}}

{{History of infectious disease}}
{{Copley Medallists 1851–1900}}
{{Académie française Seat 17}}
{{Vaccines}}
{{Authority control}}

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