Twentieth Century

1. Magic Bullets


Paul Ehrlich was a member of Robert Koch’s research team so he was aware that different microbes caused different diseases

  • He studied antibodies that develop in the body to kill bacteria without harming anything else
  • He wanted to find a chemical that could do this too – a magic bullet that would target the disease but nothing else
  • In 1905 he started looking for bullet to treat syphillis, an STI that caused disfigurement and death and was extremely contagious
  • Experimented with chemicals such as arsenic
  • He came up with 605 variations and finally version 606 worked
  • The biggest problem with Salvarsan 606 was that it killed patients!! It worked in some cases but was very risky
  • However, it is significant because it was the first time a chemical compound was used to destroy a virus


  • Research into magic bullets was interrupted by World War One – this is an example of the factor of war holding up progress in medicine)
  • In the 1920s research into chemicals to target disease began again
  • In 1932 a scientist, Gerhardt Domagk, tested a red dye (Prontosil) on mice
  • He found that it killed bacteria that caused blood poisoning in the mice
  • His daughter had an accident and cut herself, as a result she developed blood poisoning and was going to die from the infection
  • Domagk decided he had nothing to lose so he tested Prontosil on his daughter – she survived
  • The active ingredient in Prontosil was sulphonamide derived from coal tar
  • Magic bullets are also known as sulphonomides
  • Drug companies raced to discover cures based on sulphonamides
  • Within a few years cures for scarlet fever, meningitis, gonorrhoea and pneumonia had been found

2. Antibiotics






3. Technology

  • X-rays – Originally developed in 1895 by Wilhelm Rontgen, they really came into effect in World War One when finding bullets in the body. X-Rays made it possible to see inside the body without having to cut the patient open and risk infection. During the First World War they were used constantly at the front to help surgeons locate shrapnel and bullets in their patients. They became very adept at using this technique and saved many soldiers because of it. The importance of X-rays had become very apparent and the quality of images continued to improve after the war.
  • Computers – Computers and micro-technology are used widely in medicine. They assist medical research because they can process large amounts of data easily
  • Electricity – During the 20th Century, this powered many of the new medical inventions. It also became available in people’s homes and factories. This improved working and living conditions which in turn led to higher life expectancy
  • Blood transfusions -In 1901 scientists discovered that humans have different blood groups, and this explained why 19th century attempts at blood transfusion often failed. However, blood could still only be taken from a donor present at the transfusion as doctors had no way of storing or transporting the blood without it clotting. In the trenches, huge quantities of blood were needed for the injured soldiers, and doctors had to find a way of storing blood and taking to wherever it was needed. Many experiments resulted in the discovery that plasma (the liquid) could be separated from the corpuscles (minute particles). The blood cells could now be packed in ice and diluted with a warm saline solution when needed. This not only helped soldiers in but saved many civilians afterwards
  • Electrocardiograph – Developed in 1903 by Willem Einthoven it allowed a doctor to monitor a patient’s heartbeat in a more effective manner. This was highly useful in surgery to gauge how a patient was doing.
  • Microsurgery – Microscopes: Not the usual type but ones for surgery. In the 1960s it allowed surgery to be performed on blood vessels and nerves – even re-attach limbs. This led to the development of MICRO-SURGERY.
  • Transplants – Christian Barnard, a surgeon in South Africa, in 1967, transplanted a heart from a road accident victim to Louis Washkansky (he died after eighteen days). Rejection of the heart was still a problem. The drugs used practically killed off his immune system so he died of pneumonia. In the end after repeated attempts, heart transplants stopped until rejection was solved. To counter the issue of heart transplants, an artificial heart was developed. In 1982 Barney Clarke received one and lived for three weeks. However in 1974, the issue of rejection was solved. A drug called Cyclosporin was developed that reduced the risk of tissue rejection. By 1987, over 90% of transplants ended with the patient living over two years


  • Stays in hospital are getting shorter
  • More complex surgery can be undertaken
  • People can live with diseases that would have otherwise killed them – e.g. dialysis machines help people live with kidney failure
  • Technology has become miniaturised so the location of treatment has changed. Many people can treat themselves in the comfort of their own home e.g. blood pressure machines, blood testing equipment for diabetics

4. DNA

  • During the early twentieth century scientists made use of the improving technology of photography and found they were able to take photos of magnified human cells
  • They predicted that each cell contained something that determined characteristics such as hair and eye colour and inherited conditions such as cystic fibrosis and Down ’s syndrome
  • Francis Crick and James Watson, two Cambridge scientists worked together to investigate the structure of DNA
  • Crick was a physicist and Watson a chemist
  • Crick and Watson were able to build upon the earlier work of scientists who had helped improve microscopes. They also brought in other individuals at Cambridge to help them. They created a team with a wide variety of skills and knowledge. They were also able to use the improvements in genetics, biochemistry and also x-ray photography.The impact of the government and industry cannot be forgotten. They provided money for the cause. This enabled many more people to become involved and also allowed them to buy the expensive equipment needed.
  • Their work also made use of X-Ray crystallography invented by Maurice Wilkins and Rosalind Franklin at King’s College hospital in London
  • It was one of Franklin’s photos that showed that genes were arranged in a double helix structure
  • 1953 – Watson and Crick claimed discovery of the structure of DNA – many argue now that Wilkins and Franklin were equally responsible for the discovery because it was their photograph that showed the structure
  • 1990 – The Human Genome Project, led by Watson, set out to map the location of every single one of the 30,000-35,000 genes in the 23 chromosomes in every cell of the body
  • The project involved hundreds of scientists working in 18 teams
  • The first draft of the project was produced in 2000
  • Scientists have identified certain genes that pass on specific hereditary conditions


  1. There are new techniques for skin grafts, better production of insulin for diabetics, and better vaccines
  2. There is better understanding of conditions such as Down’s Syndrome and leukaemia, and whether people are more likely to develop certain forms of cancer
  3. There has been further research into techniques to alter faulty genes in the body and prevent genetic illnesses from occurring
  4. Genetic screening can be used to identify illnesses that people are likely to develop. They can then give them advice on their lifestyle in order to prevent triggering them
  5. The discovery has been made that stem cells (found in the bone marrow of long bones and the pelvis) can transform into various types of cells used around the body, which offers a chance of replacing faulty cells with healthy ones