The origin of his research dates from his reading of paper by the German physicist Mitscherlich. The latter had observed that two chemical substances, para tartrate and sodium/ammonium tartrate, had the same chemical constitution and the same crystalline form, but nonetheless had a different effect upon polarized light. Pasteur set out to discover the cause.
First Period From 1847 to 1862 (from the age of 25 to 40)
Pasteur was basically a physicist and a chemist.
1847 Studies on molecular dis-symmetry
After several years of research in which he combined crystallography, chemistry and optics, Pasteur established that there existed a parallelism between the outer form of a crystal, its molecular composition and its effect upon polarized light. Dis-symmetrical crystal caused slanting of the polarized light symmetrical crystals did not.
1855-1857 Studies on fermentation
It was while observing paratrate crystals that Pasteur had initially discovered molecular dis symmetry.
Pasteur studied lactic and alcohol fermentation, and demonstration that: all fermentation is due to the presence of a microorganism.
Second Period From 1862-1877
From the age of 40 to 55, Pasteur became a biologist. He elaborated the germ theory and abolished the doctrine of spontaneous generation.
\"Spontaneous generation is a chimera\" (Pasteur)
He next questioned the way in which fermentation works and how ferments act.
Fermentation is the consequence of life without air Experiments on fermentation led Pasteur to apply microbiological techniques to industry and agriculture.
He studied the formation of vinegar and the transformation of alcohol into acetic acid by the microorganism Mycoderma aceti, which fixes oxygen from the air on alcohol. He showed vinegar-makers how to consistently obtain high-quality vinegar.
While studying parasitic ferments of wine, Pasteur demonstrated that each disease was due to a different ferment. By heating to 550 it was possible to protect the wine from disease. This method, when applied to any liquid capable of being altered, is known throughout the world as pasteurization.
Changes in beer are produced by microorganisms found in air dust. Pasteur taught the brewers how to prevent the worst from becoming contaminated and how to prevent disease by heating the beer to 55.
In 1865, the silkworm industry in France, as well as in Italy, Australia and Asia Miner, was ravaged by a disease caused pebrine. Under the microscope, Pasteur observed that infected silkworms had shiny particles on them, which were responsible for the disease.
He demonstrated that the disease was hereditary and contagious.
Third period From 1877 to 1887 (from the age of 55 to 65)
Pasteur applied microbiological techniques to medicine and surgery.
1877 - Study of infectious diseases.
1880 - Method for attenuating microbial virulence.
Chicken cholera (by aging in contact with oxygen in the air) anthrax (by culture of anthrax-carrying germs at 430, attenuated by oxygen from the air).
By applying his method
- to the study of infectious diseases (microbial agents)
- to their prevention (asepsis)
- to their prophylaxis by immunization (Vaccination)
Pasteur was the founder of immunology.
By this time, Pasteur had thoroughly mastered his experimental methodology. When studying rabies, he sought to isolate a microbe, but could not find it. Rabies is a disease of the nervous systems. He cultured an invisible \"microorganism on rabbit marrow and fixed the virulence.
On July 6,1885, the method of, attenuation of virulent marrow was tested on a human, Joseph Meister.
November 14,1888 inauguration of the Institute Pasteur by Sadi Carnot. He died on 28.9.1895.
(Courtesy: Louis Pasteur Institute)
To commemorate the occasion Pakistan Post is issuing a commemorative postage stamp of Rs. 5/- denomination on September 28, 1995.