Modern Medicine c1900–present

The twentieth and early twenty-first centuries compress more medical change than any previous period combined. In 1900, the average British life expectancy was about 47 years; by 2020 it was about 81. Infant mortality, infectious disease and common causes of surgical death were radically reduced. The transformations that achieved this are the subject of this lesson: magic bullet drugs, penicillin and the antibiotic era, the NHS, DNA and genetic medicine, new surgical and imaging technologies, and modern public health campaigns. Running through them is a shift in the dominant factor: individuals and laboratory science remain important, but government — through the NHS, regulation, research funding and mass public health campaigns — becomes the single most powerful driver of change.

Use this lesson as the final stage in the thematic story. It is where several earlier threads (Pasteur, Jenner, Koch, Lister) come together. For Paper 1 judgement questions that span the whole period, you will often need to contrast this modern transformation with earlier continuities.

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Magic bullets: Ehrlich and Domagk

Paul Ehrlich and Salvarsan 606 (1909)

Paul Ehrlich, a student of Koch, coined the phrase "magic bullet" (Zauberkugel) — a chemical compound that would kill a specific pathogen without harming the patient. Working with Japanese chemist Sahachirō Hata, he tested hundreds of arsenic compounds against syphilis. The 606th compound worked. Salvarsan 606 (1909) was the first effective chemotherapy against a bacterial disease.

Gerhard Domagk and Prontosil (1935)

Gerhard Domagk discovered Prontosil, a red dye whose metabolite was an effective treatment for streptococcal infections. Prontosil opened the field of sulphonamide drugs, the first widely successful antibacterials.

Significance

Point
Confirmed that targeted chemical treatment of infection was possible
Built directly on Koch's bacteriology and Ehrlich's "side-chain" theory of how drugs bind to pathogens
Preceded and laid the groundwork for penicillin

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Penicillin: Fleming, Florey and Chain

The development of penicillin is Edexcel's model case study for how factors combine. No single person gave the world penicillin. Three linked contributions, across two decades, turned a chance observation into a mass-produced antibiotic.

Alexander Fleming, 1928: chance discovery

Returning from holiday to his lab at St Mary's Hospital, London, Fleming found a petri dish of Staphylococcus contaminated with mould (Penicillium notatum). Around the mould, the bacterial colonies had died. Fleming published his observation in 1929 but lacked the chemistry skills to purify penicillin in useful quantities. The substance was unstable, difficult to concentrate, and its clinical potential remained unrealised.

Howard Florey and Ernst Chain, 1939–45: purification and scale-up

At Oxford in 1939, Florey (Australian pathologist) and Chain (German Jewish biochemist, refugee from Nazi Germany) took up Fleming's paper. They developed freeze-drying and chromatography to purify penicillin. By 1941 they had enough to treat a patient (Albert Alexander, a Oxford policeman) — who improved dramatically, then relapsed when the supply ran out and died. The team realised industrial-scale production was needed.

British industry was preoccupied with the war. Florey and Chain travelled to the United States. US pharmaceutical companies, backed by government research funding as part of the war effort, developed deep-tank fermentation to produce penicillin in quantity. By D-Day (June 1944), enough penicillin was available to treat every Allied casualty; by 1945, it was entering civilian use.

The factors that produced penicillin

Factor	Contribution
Chance	Fleming's contaminated petri dish
Individuals	Fleming, Florey, Chain
Science and technology	Freeze-drying, chromatography, deep-tank fermentation
War	Military need drove funding and urgency
Government	UK and US state investment in research and industrial capacity
Communication	Fleming's 1929 publication, scientific networks across Atlantic

flowchart LR
    F[Fleming 1928: contaminated dish] --> P[1929 Lancet paper]
    P --> O[Florey and Chain Oxford 1939]
    O --> A[1941 Albert Alexander treated]
    A --> US[US pharma 1942–45]
    W[WWII military need] --> US
    G[UK and US government funding] --> US
    US --> D[D-Day 1944 wide supply]
    D --> C[1945 civilian use]

Fleming, Florey and Chain shared the 1945 Nobel Prize.

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DNA and the genetic revolution

Watson, Crick, Franklin and Wilkins, 1953

In 1953, James Watson and Francis Crick at Cambridge proposed the double-helix structure of DNA. Their model drew heavily on the X-ray crystallography work of Rosalind Franklin and Maurice Wilkins at King's College London — Franklin's famous "Photo 51" was critical, though Franklin died in 1958 and did not share the 1962 Nobel Prize.

Human Genome Project, 1990–2003

The international Human Genome Project sequenced the full human genome, completed in 2003. The implications are still unfolding: genetic testing for inherited conditions (BRCA1/2 for breast cancer risk), precision medicine, gene therapy, genetic screening in pregnancy.

Applications so far

Area	Example
Diagnosis	Genetic testing for cystic fibrosis, sickle cell, Huntington's
Treatment	Gene therapy for inherited retinal disease; CAR-T cell therapy for leukaemia
Research	Understanding of cancer as a genetic disease
Public health	Pharmacogenomics: matching drugs to patient genotype

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Surgical and imaging revolutions