19th and 20th Century

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The 19th Century (1800s)

Huge developments were made in the 19th century for several reasons:

Economic growth - trade and industry was booming, which generated money to spend on medical research and public health.

Industry growth - diseases caused by industry, such as dermatitis, or lung disease, become more common.

Urbanisation - public health diseases like cholera and typhus were common.

Growth of empires - countries came into contact with diseases new to their population, e.g. yellow fever.

Technological advancements - medical machines like the electrocardiograph were developed.

Improved communications - ideas could spread more quickly all around the world.

Wars - new weapons were created which meant new types of wounds for physicians to treat.

Democracy and socialism - the right to health was believed to be 'a right of man' e.g. by the French during the French Revolution.

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Louis Pasteur (1822 - 1895)

Pasteur is a French chemist, responsible for germ theory in 1861. He theorised that germs caused decay, and were not produced as a result of decay (as was suggested by the theory of spontaneous generation). He was mocked for his ideas by other scientists, but the government funded his research as they believed his success made France appear respectable.

Pasteur was driven by his desire to prove others wrong - he conducted experiments using a swan-neck flask:

He carried sterile swan-neck flasks down streets, before sealing them again. He kept one flask sterile. As bacteria grew in the contaminated flasks, and the sterile flask did not grow bacteria, Pasteur proved that microorganisms caused decay, not the other way around.

He carried out the above experiment in different areas, and a varying amount of bacteria grew in each flask. This proved that microorganisms were not evenly distributed.

Trade enabled Pasteur to make his first discovery when he was hired to help the alcohol industry in Lille - he discovered microorganisms in the alcohol, causing it go sour. The development of the microscope also enabled him to discover these microorganisms. He was later hired to help the silk industry, as many silk worms were dying; he discovered a disease-causing bacteria infecting and killing the worms.

Pasteurisation was Pasteur's suggestion to gently heat alcohol and milk to kill organisms, and make them safe to drink. He proved this by gently heating liquid in a flask to sterilise it, and then sealing the flask. The flask remained sterile for 100 years, and pasteurisation is still used today.

Robert Koch (1843 - 1910)

Koch was a doctor, so had a detailed understanding of human anatomy (which Pasteur lacked). In 1872, Koch began to experiment with microbes in a small lab he had built in his surgery.

After his first discovery of a specific germ that caused anthrax, Koch had discovered the final proof of germ theory. Koch's work was funded by the German government, for the same reason that Pasteur's work was funded by the French. The Franco-Prussian war of 1870 - 1871 created rivalry between the countries, and so both Pasteur and Koch were determined to 'beat' one another.

Koch himself developed the process of staining bacteria, so they could be photographed (in high-quality - new high-quality photographic lenses helped his discoveries) and studied in detail. He also discovered how to grow bacteria on potatoes, which made them easier to study than when they were in liquid.

A timeline of the two - both Pasteur and Koch made discoveries that were fundamental for the other to further their work.

1873 - 1880 - Koch

-> investigated anthrax and discovered the specific bacterium that caused it; it was the final proof for germ theory and the first time a specific germ that caused an individual disease had been identified.

-> developed a way to stain bacteria so they could be photographed and studied in detail.

-> discovered how to grow bacteria on potatoes, so they were easier to study.

1879 - 1881 - Pasteur

-> discovered bacterium causing chicken cholera.

-> discovered a vaccination for chicken cholera; he had left one of his workers to inoculate chickens with the disease, but the worker forgot. When the worker returned (after the lab had closed for the summer), he inoculated the chickens with the old germs, but the chickens did not die as was expected. He inoculated them then with fresh germs, but they still did not die.

-> this led to the development of the anthrax vaccine, which he tested on animals and successfully tested in public.

1881 - 1882 - Koch

-> used his method of staining bacteria to make the bacteria stand out from human tissue and other bacterium.

-> this was a major breakthrough that lead to the discovery of specific bacteria which caused: typhoid (1882); cholera (1883); tetanus (1884); pneumonia (1886); meningitis (1887); plague (1894); dysentery (1898).

1881 - 1883 - Pasteur

-> success with animal vaccines inspired him to develop human vaccines.

-> he developed a vaccine against rabies, which he successfully tested on dogs.

-> the first test on humans was done in 1883, on a young boy, Joseph Meister, who was bitten by a dog and infected. Pasteur gave the boy 13 injections over 2 weeks, and the boy survived.

-> this success led to the development of other vaccines against human disease: typhoid (1896); tuberculosis (1906); diphtheria (1913); tetanus (1927).

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The Development of Penicillin

1872 - Joseph Lister notices a mould of bacteria (penicillin) killed other bacteria. In 1884, he uses the mould to treat a nurse with an infected wound, but does not use it again.

Early 1900s - the first chemical cure for disease is developed by Paul Ehrlich; it destroys the bacteria that caused syphilis. It's called a 'magic bullet', which is a tablet that goes straight to the site of infection.

1928 - Alexander Fleming

1939 - Howard Florey and Ernst Chain

Technology - mass production of penicillin made enough for it to be useful and used as an antibiotic.

War - Fleming wanted to treat infections because of his work with WWI soldiers - no chemical antiseptics could save them; America joined WWII in 1941, and saw the potential of penicillin to use to treat soldiers, so funded the research.

Government - the American government provided 5 years worth of funding and gave interest-free loans to US companies to buy expensive equipment to mass produce penicillin.

Fleming (1881 - 1955)

In 1928, in a London hospital, Fleming rediscovered the properties of penicillin. He was growing cultures in a laboratory for testing - he did not like to throw away cultures before he was certain there was nothing more to learn from them, so left cultures in the sink waiting to be washed up. He left the lab for a while, and when he returned, he noticed that there was some mould in one of the dishes, and that the bacteria that had been growing wasn't growing near the mould. Fleming recognised the significance of this, so decided to test the mould to discover what it was.

Fleming was unable to produce enough penicillin to make it useful as an antibiotic, but he recorded the findings of his experiments in a medical journal in 1929.

Florey (1898 - 1968) and Chain (1906 - 1979)

In 1939, Florey and Chain were two scientists researching how to kill germs, and came across Fleming's article. They attempted to get funding from the British government to do further research into penicillin, but received only £25. By 1941, they had produced enough penicillin to treat one man, Albert Alexander, who had septicaemia. Penicillin proved effective, until they eventually ran out, and Alexander died.

That same year, Florey went to America for funding. America had just been attacked by Japan at Pearl Harbour, and the government saw the potential of penicillin in treating the wounded. The support of the American government and companies led to mass production of penicillin.