Germ Theory

• Common theories about the cause of disease before Louis Pasteur


  • Miasma - bad poisoned air causes disease
  • Spontaneous generation - idea that rotting things generate germs on their own
  • Belief that germs were the product of decay and not the cause
  • Belief that maggots and flies spontaneously generated
• Germ Theory


  The theory that microbes in the air cause substances to rot and go bad, leading to disease
• Louis Pasteur


  19th-century French scientist who made breakthroughs in germ theory
• Louis Pasteur's swan-necked flask experiment

  1. Stage 1: Boil broth to kill any germs

  2. Stage 2: Divide broth between two flasks, one with a straight neck and one with a swan neck

  3. Stage 3: Leave the flasks open to the air and observe results
• Pasteur developed the pasteurization process for extending the useful life of liquids
• Pasteur published his germ theory


  1861
• Pasteurization process

  Fresh milk is heated to kill germs, then cooled down to keep it fresh, and finally, it is put out as pasteurized milk
• German scientist Robert began to prove that specific germs caused specific diseases


  Progress in public health, vaccines, and improved surgery followed
• Weakened forms of germs in vaccines prepare the body to fight diseases
• Improved surgery, such as Lister's carbolic and antiseptics, was developed
• Stages of Pastor's Germ Theory development

  Stage 1: Between 1861 and 1864, Pastor was coming up with the Theory and trying to prove it. Germfu was published in 1861. In 1864, he carried out experiments that convinced other scientists his theory was correct. However, he could not identify specific bacteria that cause specific diseases.

  Stage 2: Between 1865 and 1876, Pastor struggled to prove his theory and couldn't distinguish the bacteria that caused cholera. This was later done by German biologist Robert. The invisibility of bacteria led people to still believe in the miasma Theory.

  Stage 3: In 1876, anthrax was a breakthrough. Robert found the bacterium that caused Anthrax, the first time a specific microbe causing a specific disease was identified.

  Stage 4: In 1877 and beyond, Pastor created more vaccines. He investigated chicken cholera and accidentally vaccinated test hands with an old batch of the disease, leading to the discovery that germs could be weakened and deactivated to produce vaccines. He also developed a vaccine for rabies in the 1880s.
• Louis Pasteur was a French scientist
• Pasteur used the swan neck flask experiment to prove that microbes in the air cause liquids to go bad
• In 1861, Pasteur published Germ Theory showing that illness was caused by microbes
• Pasteur developed pasteurization to preserve liquids
• Pasteur's work led to greater developments in surgery, public health, and vaccines
• Pasteur inspired other scientists like Robert who built on his ideas
• Pasteur's identification of the actual cause of illness had a significant impact
• Understanding the actual cause of disease allows for more effective ways to fight it
• Progress in medicine has been rapid since the identification of the actual cause of disease
• Speaker: 'Goodbye and good health'