For
many years people died of diseases and no one knew why. It was many
years before scientists realized that the causes of most diseases
were microorganisms,
or germs. They began to study ways to fight these microscopic disease
causing creatures.
In
1796 Edward Jenner discovered a safe and sure way of preventing a
terrible epidemic disease called smallpox. He laid the groundwork for
the science of immunology
by using cowpox vaccine
to inoculate against smallpox.
Louis
Pasteur, a French scientist, uncovered important facts about bacteria
during the 1800's . He invented the
process of pasteurization,
or heating to kill microorganisms, and developed vaccines for several
diseases including, rabies.
A
German doctor named Robert Koch proved that bacteria causes a lot of
diseases. Robert Koch discovered a number of major diseases. In 1882
Koch isolated a bacillus that was the germ that cause
tuberculosis.
The
word virus
was not used until the 1800s when scientists described germs that
caused diseases that were smaller than bacteria.
Penicillin,
is a powerful drug used to treat infections caused by bacteria. It
was the first antibiotic
(drug produced by microbes) used successfully in the treatment of
serious diseases in human beings. Sir Alexander Fleming, a British
scientist, discovered penicillin in 1928.
Many germs can be used to make vaccines to protect
people from getting certain diseases.