Louis Pasteur and germ theory

• Miasma


  Bad poisoned air causes disease
• Spontaneous generation


  Rotting things generate germs on their own as part of the rotting process
• Germ Theory


  Microbes in the air cause substances to rot and go bad and therefore germs in the air cause disease
• Louis Pasteur


  • 19th century French scientist
  • Not initially working directly to improve medicine
  • Theorized that something in the air, possibly microbes, might be to blame for wine and beer going sour
• Pasteur's swan-neck flask experiment


  1. Boil broth to kill any germs

  2. Divide broth between straight-neck and swan-neck flasks, both open to air

  3. Straight-neck flask broth went bad, swan-neck flask broth stayed fresh

  4. Concluded that airborne germs got trapped in the bent section of the swan-neck flask
• Pasteur published his Germ Theory


  1861
• Pasteurization


  Process named after Pasteur for extending the useful life of liquids by heating to kill germs
• Pasteur's Germ Theory


  Faced resistance until the 1870s when German scientist Robert began to prove that specific germs caused specific diseases
• Pasteur's work on germ theory

  1. Stage 1 (1861-1864): Pasteur developed and proved his theory

  2. Stage 2 (1865-1876): Pasteur struggled to prove his theory, as bacteria were invisible and people still believed in miasma theory

  3. Stage 3 (1876): Robert found the bacterium that caused anthrax, the first time a specific microbe was linked to a specific disease

  4. Stage 4 (1877 and beyond): Pasteur instrumental in creating more vaccines, including for chicken cholera and rabies
• Pasteur's work led to greater developments in surgery, public health, and vaccines
• Pasteur's identification of the actual cause of illness was a major breakthrough, replacing previous incorrect theories