Changes in the Understanding of Disease Revision:
1. 19th Century ideas about Diseases:
a. A minority of people believed in the idea of the four humours (blood, yellow bile, black bile,
phlegm).
b. The idea of miasma (bad air). People believed that diseases were caused by being exposed to
bad air.
c. In the 19th Century, many doctors believed in the idea of Spontaneous Generaton. In 1860,
Pouchet, a French scientst, carried out experiments supposedly to prove this theory.
Key Inventon: In the 1600s, a Dutchman, Key Theory: Spontaneous Generaton:
Anthony van Leeuwenhoek, made a The idea that organisms were the result of
microscope that magnifed things up to 3000 decay.
tmes. In the 1800s, ooseph Lister Sr. Decaying mater itself turns into
developed a microscope that could magnify organisms.
things up to 1000 tmes. Scientsts used new microscopes (developed
This allowed scientsts to study by Lister Sr.) to study microbes on rotng
animalcules in detail. food to try and see where they came from.
They concluded that micro organisms were
the result of decaying food.
2. The Role of Pasteur:
a. Pasteur’s early experiments:
In the1850s, Pasteur carried out a series of experiments on vats of alcohol, from a brewing
company, to fnd out why they kept turning bad.
He found microbes germinatng in the liquid and concluded that this was what was making the
alcohol go bad.
He carried out the same experiment on wine, vinegar and milk.
In 1860, Pasteur carried out some of his experiments in public to prove his discovery to other
scientsts, however, they were not convinced.
Key fgure: Louis Pasteur: Pasteur was a French chemist, born in 1822 and died in 1895.
He was the frst person to prove the connecton between germs and decay. He made
many of his investgatons for businesses who had problems that were losing them
money.
b. The discovery of Germ Theory 1861:
In 1857, Pasteur investgated sugar beet, a substance in beer, which turned sour during
fermentaton. Upon investgaton, Pasteur discovered that germs were causing the souring.
1. 19th Century ideas about Diseases:
a. A minority of people believed in the idea of the four humours (blood, yellow bile, black bile,
phlegm).
b. The idea of miasma (bad air). People believed that diseases were caused by being exposed to
bad air.
c. In the 19th Century, many doctors believed in the idea of Spontaneous Generaton. In 1860,
Pouchet, a French scientst, carried out experiments supposedly to prove this theory.
Key Inventon: In the 1600s, a Dutchman, Key Theory: Spontaneous Generaton:
Anthony van Leeuwenhoek, made a The idea that organisms were the result of
microscope that magnifed things up to 3000 decay.
tmes. In the 1800s, ooseph Lister Sr. Decaying mater itself turns into
developed a microscope that could magnify organisms.
things up to 1000 tmes. Scientsts used new microscopes (developed
This allowed scientsts to study by Lister Sr.) to study microbes on rotng
animalcules in detail. food to try and see where they came from.
They concluded that micro organisms were
the result of decaying food.
2. The Role of Pasteur:
a. Pasteur’s early experiments:
In the1850s, Pasteur carried out a series of experiments on vats of alcohol, from a brewing
company, to fnd out why they kept turning bad.
He found microbes germinatng in the liquid and concluded that this was what was making the
alcohol go bad.
He carried out the same experiment on wine, vinegar and milk.
In 1860, Pasteur carried out some of his experiments in public to prove his discovery to other
scientsts, however, they were not convinced.
Key fgure: Louis Pasteur: Pasteur was a French chemist, born in 1822 and died in 1895.
He was the frst person to prove the connecton between germs and decay. He made
many of his investgatons for businesses who had problems that were losing them
money.
b. The discovery of Germ Theory 1861:
In 1857, Pasteur investgated sugar beet, a substance in beer, which turned sour during
fermentaton. Upon investgaton, Pasteur discovered that germs were causing the souring.
