Inventions – Germ Theory Of Diseases
Each time we go to the refrigerator and take out a bottle of milk, we should be
reminded of the work of the outstanding French scientist, Louis Pasteur. Pasteur
discovered that milk turns sour because of the action of tiny living organisms too
small to see with the naked eye. He developed a process of gently heating foodstuff
like milk to kill these organisms without changing the flavour or nutritional value.
This process, named ‘pasteurization’ in honour of its developer, is just one of
Pasteur’s great contributions to science. He is also known for his invention of
Germ Theory of Diseases.
As per Biography of Louis Pasteur, he was a world renowned
French chemist and biologist. He was born on December 27, 1822 in the town of Dole
in Eastern France. Pasteur's parents were peasants. Curiously, although young Pasteur
worked hard as a student, he was not considered to be exceptional at chemistry.
In 1847, Pasteur was awarded his doctorate and he then took up a post as assistant
to one of his teachers. He spent several years teaching and carrying out research
at Dijon and Strasbourg and in 1854 moved to the University of Lille where he worked
as a professor of chemistry.
Pasteur discovered the method for the attenuation of virulent micro-organisms that
is the basis of vaccination. He developed vaccines against chicken cholera, anthrax
and swine erysipelas. After mastering his method of vaccination, he applied this
concept to rabies. On July 6, 1885, Pasteur tested his pioneering rabies treatment
on human being for the first time: the young Joseph Meister was saved.
When he was only twenty-six years old, Pasteur solved a problem that had been puzzling
the great chemists. He found that when light was passed through tartaric acid -
this was found in wine dregs, it produced a strange effect. Pasteur proved that
this was because the acid is actually not one acid but mixture of different acids.
This work in fermentation enabled Pasteur to identify that the changes brought about
when beer, wine ferments, milk turn sour or meat decays when special micro-organisms
The souring of wine and beer was a major economic problem in France. Pasteur looked
at some droplets of bad beer through a microscope and observed that the beer contained
small rod shaped bacteria, instead of round yeast cells. Although micro-organisms
are essential in fermentation they must be the right ones. This was a major discovery.
Pasteur made brewing a more scientific procedure and showed brewers how to culture
the right organisms for good beer.
By 1857, Pasteur had become world famous and took up an appointment as director
of scientific studies at ‘Ecole Normale’ in Paris. He was asked to help to investigate
a serious disease that was ruining the silk industry in southern France. Pasteur
observed through his microscope that the diseased caterpillars and eggs all contained
tiny organisms. He identified these as disease producing organisms. Pasteur was
able to show that the worms fed on diseased smeared leaves got the disease, whereas
those fed on uncontaminated leaves remained disease free. He then worked with the
silk industry to devise a simple way of keeping silk worms under healthy conditions
and therefore disease free. Not only had Pasteur rescued the French silk industry
but he had established the connection between bacteria and disease.
In France, many cattle suffered from anthrax, a serious disease from which many
of them died. Pasteur made a careful study of anthrax and noticed that if it were
possible to give an animal a mild attack, this might be sufficient to prevent it
from getting the disease later on.
Pasteur worked throughout the rest of his life on the various causes of diseases
and how these could be prevented by vaccination. On March 1886, Pasteur was invited
to present his results to the Academy of Sciences and in 1888, went on to establish
the ‘Pasteur Institute’ in Paris. This was a pioneering clinic for the study of
infectious diseases, the treatment of rabies and a centre for teaching. Pasteur
directed the Institute personally until he died. The Pasteur Institute is one of
the most important centres in the world. Pasteur became a national hero and was
honoured in many ways.
On September 28, 1895, he died in Paris. His last words were: ‘One must
work; one must work. I have done what I could.’