Louis Pasteur (1822-1895) was a French Chemist and microbiologist. He is best known for discovering the germ theory of disease. His germ theory of diseases and consequent efforts to kill the germs that cause diseases prevent diseases.
Before Pasteur’s time, folk did not understand how diseases were caused in the human body and his studies showed how germs enter the human body and cause it to malfunction.
Pasteur also made the seminal discovery of how to prevent milk from rotting (caused by germs) through what is now called pasteurization (initially heating the milk to kill potential germs and then ceiling the milk container in such a manner to prevent new germs from entering it).
Louis Pasteur is one of the founders of the field of microbiology.
Initially, Pasteur studied physics and did some research on light and crystals. We shall not concern ourselves with all aspects of Pasteur’s work; we are only interested in his seminal contribution to science, his germ theory of diseases.
Pasteur performed experiments. In one a broth was left in an enclosed situation where nothing from the environment could reach it, and in another the broth was in the open where anything in the air could reach it. He noticed that the broth in the open had things growing on it, whereas the enclosed broth did not have things growing on it. He reasoned that spores carried by dust must have landed on the open air broth and finding it a source of nutrient grew on it.
What Pasteur was saying is that things do not grow spontaneously but because something made them grow. Spores are carried by wind and dust and if where they are dropped is fertile they grow.
Germs do not grow spontaneously in the human body; they are caused by germs that were, in one form or another, brought to the body.
There are millions of microorganisms; some of them cause harm to human bodies but others are harmless. Indeed, some are very useful in the human stomach.
Some microorganisms contaminate beverages whereas others are useful for beverages. Yeast is used in fermenting the material (such as wheat) employed in making beverages (wine, bear etc).
Pasteur contributed to immunology and vaccination. He was able to inoculate against cholera by identifying the bacteria that caused it and somehow kill it and give it to folk and subsequently when their bodies recognize cholera producing germs kill them, for they had developed immunity to them (can easily produce antibodies to kill them).
Today we inoculate folk against diseases by injecting them with the weaker forms of the bacteria that causes those diseases.
Edward Jenner discovered the process of weakening germs and injecting them into people to have their bodies develop immunes to them; specifically, he did this with the germs that cause smallpox.
Today, just about all children are vaccinated against small pox and other germs.
Pasteur’s work and the work of other microbiologists, such as Edward Jenner, built the foundation of modern medicine. Just think that until these men came along doctors used to operate on patients without washing their hands and go from one patient to another and in the process transfer germs from one patient to another. Doctors were killing more patients than the diseases that they were supposed to be curing.
Pasteur had allegations of deception made against him. His studies of anthrax and immunization against it were challenged. I will not go into that controversy. I am only here to point out that Louis Pasteur contributed to the germ theory of diseases. Whatever else he may have done, this contribution saves millions of people from diseases and death. For this work he is one of the greatest men of science that have ever lived. If you doubt it, remember that without him you might have died in childhood from assorted diseases that immunization now prevent.
Louis Pasteur. Catholic Encyclopedia. (1913)
John Hudson Tiner. Louis Pasteur: Founder of Modern Medicine. (1990)