Pasteur
Achievements: Discovered germ theory
Born: December 27, 1822; Dole, France
Died: September 28, 1895; Villeneuve L'Etang, near Paris, France (Aged 73)
Field & Discipline: Science; Microbiology; Chemistry; Immunology
Education: Local schools, Arbois; Royal College, Besancon; Ecole Normale Superieure, Paris
Life & Times:
While still a student, Pasteur separated the two crystalline forms of tartaric acid and found that each had a different effect on polarized light. He had discovered the phenomenon of isomerism (where two compounds have different properties, although both are made up of the same elements, in the same proportions and the same molecular weight).He showed that it is the way their atoms are grouped or arranged that accounts for the difference in behaviour between the two substances (some historians think this idea as important as germ theory). He also showed that micro-organisms exist in only one of the two isomeric forms.He presented his conclusions before the Paris Academy of Sciences in 1848. In the same year he became Professor of physics at a secondary school in Dijon and soon afterwards went to Strasbourg University as professor of chemistry.
In 1854 he was appointed dean of the new Faculty of Sciences at Lille University. He fostered closer co-operation between science and industry by taking his students round factories, organising practical courses, and setting up evening classes for local craftsmen. One industrialist, who made alcohol from grain and beet sugar, wanted to know what to do about the spoilage which appeared during the fermentation of sugar into alcohol by yeast.Pasteur suspected that yeast was a micro-organism, and that it was the presence of other micro-organisms which produced the spoilage. He stated that fermentation was the result of the activity of a micro-organism, and that when fermentation failed to occur, this was due to the absence of the micro-organism, or the lack of the right conditions for the survival of the micro-organism.
He went on to say that each particular type of fermentation was the effect of a specific micro-organism - or “germ” - acting on a specific type of substance to produce another substance. He demonstrated this by showing how sugar could be converted into lactic acid, butyric acid or alcohol, and how alcohol could be converted into acetic acid.He published his germ theory of fermentation in 1857, and stated that the different types of micro-organisms could be separated from each other, that each required different conditions for their survival, and was differently susceptible to antiseptics.He extended his theory beyond fermentation to disease, stating that many types of diseases were caused by a specific germ. Pasteur also discovered that certain micro-organisms are anaerobic i.e., they do not need oxygen to survive or reproduce themselves.
In 1857 Pasteur was appointed director of scientific studies at the Ecole Normale and later took on the additional job of teaching science at the Ecole des Beaux-Arts. In 1865 he was asked by the government to investigate silkworm diseases which were threatening the vital silk production industry in France.He went south to live in Cevennes, the centre of silkworm breeding in France, and he set up a primitive laboratory. After three years he had isolated the bacilli of two diseases and was able to recommend preventative techniques.
Pasteur was freed from his teaching and administrative duties when a laboratory of physiological chemistry was established for him at the Ecole Superieure in 1867. He was ill in 1868 and left partially paralysed but nevertheless began research into the origin of micro-organisms.At that time, micro-organisms were thought to originate by spontaneous generation during processes which took place in organic material, such as the souring of milk, the fermentation of grape juice, and the putrefaction of meat. Pasteur demonstrated that this idea was false. He recognised that fermentation was speeded up by exposure to air, and suggested that micro-organisms could be present in the air already, an idea earlier put forward by [anticipated by] Spallanzani*.
Pasteur did experiments which proved that food decomposes when exposed to air, showing that the air contains micro-organisms which cause putrefaction, rather than micro-organisms spontaneously generating in the putrefied food. He applied his theory to wine and vinegar and introduced the process of pasteurization i.e., the technique of destroying micro-organisms, or “germs,” by heat.
In 1870 he developed a process for the production of beer which prevented its deterioration over time. A government grant in 1874 enabled him to continue his research free from financial worries, and Pasteur began looking for ways to reduce the effects of disease-producing micro-organisms, and limit their spread.He stressed to surgeons that there was more risk from germs on their hands and instruments than from the air surrounding them; and his support of antisepsis and the use of sterilization in hospital procedures led the use of the autoclave, whose prototype had been invented by the French scientist [anticipated by] Papin* two centuries earlier.
By observing the progress of disease in animals and fowls, Pasteur found that animals who had recovered from some diseases were then immune to further infection by those diseases.He cultivated weakened cultures of various micro-organisms and found that by inoculating fowl with a weak culture of the micro-organism responsible for chicken cholera he could protect fowl from outbreaks of the disease. Similarly, he successfully vaccinated a herd of sheep against anthrax.
In 1882, inspired by the vaccination work of Edward [inspired by] Jenner* he began investigations on the preventative treatment of rabies , a disease affecting dogs, which could be passed to humans by a dog bite and was always fatal. He found that the virus was present in the nerve centres of infected dogs and managed to produce a weak form of the virus with which to vaccinate a rabies patient.On 6 July, 1885, the treatment was applied for the first time ever toJoseph Meister, a boy aged nine who had been bitten by a rabid dog. After the [developed] vaccination*, Meister recovered. Three years later the Paris Pasteur Institute was established for research into the prevention and treatment of rabies. Pasteur remained as head of the institute until he died.
EXTRA CONNECTIONS: [painted by] Cormon* painted his portrait on a ceiling.
Presided at Chemical Society meeting when [knew] Kekule* presented his benzene theory.
Met (and quarrelled with) [disagreed with] Koch*
Vindicated[vindicated] Holmes’* views on hygiene and contagion.
Inspired [inspired] Eijkmann*
Disagreed with [disagreed] Liebig*
He influenced [influenced] Lister*
His work related to the [work related to] phylloxera* problem
An admirer was [a fan was] Virchow*
He was psychically attacked by anti-vivisectionist Mary [psychically attached by] Kingsford*
Assessment: Pasteur made a revolutionary contribution to the germ theory of disease and his work saved not only countless human lives but also the wine, beer and silk industries of France.
Oneliner: Louis Pasteur, discoverer of germs
Bibliography:
- Vallery-Radot, Rene, The Life of Pasteur, Constable & Company, Ltd., 1919.
Father: Jean Joseph Pasteur
Mother: Jean Etienne Roqui
Siblings: 3 sisters
Spouse: Marie Laurent
Children: 2
Language: French