Medicine 1350-Present Day
Changing explanations 0f
the causes of illness and
disease
Ideas of the Causes of Disease 1350-1750
The Ideas of Hippocrates:
•
Greek Doctor (Ancient Greece around 600BC onwards.) They
believed mainly that the gods caused disease.
•
Hippocrates believed people became ill when the 4 humours (liquids)
in their bodies were unbalanced eg too much phlegm can be seen
when people have a cold and their nose runs, or they throw up.
•
Hippocratic Oath- standards of treatment, behaviour and work for
benefit of patients only.
•
The Hippocratic collection of books may not have all been written by
Hippocrates but they are the first detailed lists of symptoms and
treatments.
•
Focused on recording of the progress of diseases so that doctors could
see if treatments helped and use them on future patients.
•
Hippocrates told doctors to use natural treatments as the causes of
disease were natural eg exercise and a good diet. If necessary patients
should be bled or purged.
The Ideas of Galen:
•
A Roman doctor who was born AD129 and educated in Greece
before going to Akexandria in Greece and then travelled to Rome
becoming a surgeon at a gladiators schoo and doctor to the Emperorl.
•
Believed in the 4 humours but took idea further and built on
Hippocrates’ ideas with the idea of ‘opposites’ to balance them eg too
much phlegm = cold so treat with something like pepper.
•
Emphasised Hippocrates methods of observing and recording
•
Encouraged doctors to use natural treatments and exercise.
•
He dissected human bodies in Alexandria but had to use animals
most of the time in Rome. He proved the brain controlled the body
and blood flowed in arteries.
•
Galen wrote 60 books and they became the basis of medical teaching
and learning for the next 1500 years.
Ideas of Causes in the Middle Ages
Multi causal approach to understanding causes of disease:
Galen’s ideas were still the basis of medical teaching- humoural
theory and the theory of opposites.
Supernatural causes- Punishment by God for sins, this could be a
personal cause for that individual or a punishment for society as a
whole , possession by the Devil, cursed by a witch.
They also believed that the position of stars and planets could
influence people’s wellbeing and that star signs as well as the four
elements- earth, air, fire and water would predisposition
individuals to certain tendencies in terms of ill health.
Physicians used a Latin handbook ‘vade mecum’ which means ‘Go
with me.’ The manuals included urine chart and zodiac charts to
help to diagnose illnesses.
Case Study 1: The Black Death, 1348.
Killed about 1/3rd of the population of
England.
What did they believe caused the Black Death?
1. A punishment from God- he was unhappy or testing the
faithful. The Flagellants whipped themselves to ask for His
mercy.
2. The position of the planets- Mars, Jupiter and Saturn.
3. Bad/ poisonous air called miasma.
4. Imbalance of the four humours.
5. Activities of ‘outsiders’ such as Jews or witches.
The Medical Renaissance
and Scientific Revolution 1450--1750
This was a time when educated people began questioning old
ideas in many different scientific areas. For example Galileo
studied the sun and stars and questioned whether the sun moves
around the earth. He put forward the idea that the earth actually
travels around the sun. Renaissance means ‘rebirth.’
For the first time in medicine doctors also began to question
what the Ancients had taught. Pre-existing ideas about the causes
of disease began to be challenged.
The printing press was also invented which meant far more
people could have access to affordable texts, so aiding the spread
of ideas.
The Scientific Revolution saw a quest for experimenting and
finding empirical evidence which triggered research into the
causes of disease.
Case Study 2: The Great Plague, 1665.
Killed 65,000 in London alone.
What did they believe caused the Great Plague?
1. A Blazing comet was seen in the sky.
2. God was punishing their sins.
3. Servants brought it into their houses after the sick breathed
on them.
4. It came from the sweat or stench of the sores of the sick.
Invisible creatures were carried on the air and got into
peoples pores or were breathed in.
There was a reduction in the emphasis on supernatural or
astrological causal explanations (1 &2) and an increased focus
on common sense natural explanation of causes (3 &4)
Ideas on the Causes of Disease 17501860
Miasma or Bad Air- In the early 1800s people believed that nasty fumes
that came off rubbish and decaying things. Growing towns were full of
disease and terrible smells.
Spontaneous Generation- the idea that rubbish or decaying materials
create small organisms eg a rotting orange turns into maggots and flies.
By 1861- the existence of germs had been proved and they had been
linked to disease.
How was the link between germs and disease made?
Stages in the development of Germ Theory:
1. Late 1600s Anthony van Leeuwenhoek made an early microscope and noticed
tiny organisms he called animalcules. He wrote 200 papaers for the Royal
Society in London.
2. In 1830 Joseph Lister used new purer glass to make a microscope that
magnified 1000 times without distortion.
3. In the 1850s Louis Pasteur, a French scientist, was asked by a brewing company
to find out why vats of beer were going bad. He found an organism germinating
(growing) in the liquid, he called them germs and realised they must be making
it go bad. He showed the brewers that they could kill the organisms by boiling
the liquid and solved their problem. He went on to the same for wine, milk and
vinegar suppliers. In the 1860s Pasteur was asked to investigate a disease in
silkworms and he found a micro-organism was causing it.
4. In 1860 the French Academy of Science organised a competition to prove or
disprove Spontaneous generation. Scientists wanted to find out where microorganisms came from. Pasteur entered the competition against Pouchet,
another French scientist. Pasteur devised a series of experiments to prove
microbes in the air case decay and can be killed by boiling. In 1861 Pasteur
published his “Germ Theory.” He also suggested that if germs make beer go
bad, maybe they do the same to animals and humans.
Pasteur’s contribution
Positive:
His Germ Theory suggested germs caused disease and put
an and to old ideas such as the 4 humours and miasma.
He developed vaccines to prevent Chicken Cholera and
Rabies.
He inspired Robert Koch who took up the challenge of
applying Pasteur’s work to human diseases. Pasteur also
inspired others to discover other bacteria eg Typhus 1880
and Plague 1894.
Limitations to Pasteur:
He didn’t actually link human disease to bacteria, Robert Koch
did.
He only discovered the way of vaccinating against Chicken
Cholera by luck, his assistant accidently used an old weakened
batch of cholera matter when experimenting.
Koch developed more vaccines, based on identification of
specific bacteria eg He studied Anthrax and his team went on to
identify the bacteria causing TB 1882 and Cholera 1883. His
work on using solid cultures, instead of liquid cultures, led to
the development of cures as well because they were easier to dye.
He had discovered the cause of infectious diseases but not the
causes of other types of illness or disease eg hereditary,
environmental and lifestyle.
What factors helped Pasteur discover his Germ Theory?
Science and
Technology
Chemistry had helped people to understand better how the body
worked.
By the 1800s purer glass meant microscopes were much stronger and
bacteria could be seen clearly.
Industry
A brewing company paid Pasteur to solve their problem with beer going
off.
The Silk Industry paid him to help with ill worms.
Poultry farmers paid him to prevent Chicken Cholera.
Government
The French Academy of Science organised the competition that made
Pasteur and his theory famous.
The French government gave Pasteur the money he needed to hire a team
of doctors to help his research.
Communicati
ons
1861 Pasteur published his theory and it immediately sold well.
By the 1880s people came from all over Europe to Paris to be treated by
Pasteur.
War
France lost a war against Germany 1870-71. Thishis had caused bitter
rivalry between the nations, Pasteur hated that Koch, a German, seemed
to be getting ahead of him, so he pushed
Robert Koch
German doctor interested in Germ Theory. Bought microscope and
1875-78 studied Anthrax, a disease affecting people and animals.
Impressive research led to German government giving him a job and a
team of bacteriologists.
What did he do? He took the organs from a sheep who died from
Anthrax and found bacteria. Took bacteria sample, grew it, studied it
and injected it into a mouse. Took blood from infected mouse and grew
bacteria from it to check it was the same. Then injected into another
mouse and continued. Repeated process through 20 generations of
mice. Many scientists followed this process.
Koch then developed a new solid medium to grow bacteria in. He also
found a way to stain bacteria so they were more easy to study- the most
important was the bacteria microbes which cause Blood Poisoning,
which he stained purple. This later aided Domagk, development of
Prontosil to treat blood poisoning.
The Discovery of DNA
What is DNA? Strings inside the cells of our bodies. DNA carries the
instructions for our bodies and everyone’s is different.
Early 20th Century- scientists knew about DNA but couldn’t understand
how.
In 1953 in Cambridge Crick and Watson discovered the structure was a double
helix joined by bases like the rungs of a ladder. They proved it was a blueprint
for life passed on from one generation to the next.
Crick- trained as a physicist in London then changed to molecular biology and
genetics.
Watson- an American started his research aged 15 at Chicago University.
Together they inspired each other, they were described as fun-loving, ambitious,
merciless and totally honest with each other. They worked with other people at
Cambridge such as Wilkins and Franklin.
Individuals- Crick and Watson, both experts in their fields, who as individuals
had adventurous characters and who were willing to go out of their comfort
zones.
Teamwork- they worked with a large team of scientists. Maurice Wilkins was
an expert in X-Ray photography. Rosalind Franklin developed a technique to
photograph a single strand of DNA.
Earlier research and discoveries- for hundreds of years scientists knew that
some illnesses were passed on through families. Scientists had used
microscopes to see how cells in the body were made up.
Technology and science- scientists used new knowledge from all areas of
science such as genetics and biochemistry. They also used new technology and
equipment like x-ray photography and improved microscopes..
Money- funding came from two sources, governments and industry. This
research was very expensive because of the types of technology and the highly
skilled people it needed.
The Human Genome Project- how did they do it?
In 1990 the Human Genome Project set out to map each of the 100,000
genes in our bodies and their purpose. They complete it in 2001.
1.
Research teams in 18 countries took part. (the USA, Britain , Japan,
France, Canada. Each team took a different part of human DNA.
2.
Money came from governments and large drug companies who hoped to
profit from drugs based on DNA.
Computerisation was vital to analyse and record the huge amounts of
data. The information found would fill over 80,000 books but could be
stored on 5 CD-ROMS. The internet allowed the data to be passed
around the world in minutes.
This development has aided our understanding of genetically causes diseases:
Some forms of cancer, diabetes, Down’s Syndrome, cystic fibrosis, parkinson’s
disease, Alzheimer’s disease.
3.
What else have we learned about what
causes disease in the 20th Century?
We now know that lifestyle is a significant cause of
illness. Smoking, alcohol, sun exposure, poor diets
and lack of exercise are all examples
We are also aware of environmental causes, such as
to chemicals, insecticides, pollutants etc.
Heart disease, stroke and cancer are three of the
biggest killers today.