Germ Theory

• why was the discovery of germs such a huge turning point

  diseases can be treated effectively- no more 4 humours or opposites cures. vaccines can be understood, explained and manufactured. better prevention methods and better sanitation- sewers, clean water. surgery becomes safer
• before Pasteur


  most people believed miasma to be the cause of disease until Pasteur. 1677 Anthony van Leeuwenhoek invented a microscope. he called the tiny creatures he saw animalcules. Royal society published his findings in 200 papers. spontaneous generation was the theory that these animalcules simply appear on decaying matter
• better technology


  Joseph Lister created a new microscope using new types of glass produced as a result of the industrial revolution. magnified things by 1000
• who was Louis Pasteur

  French scientist studying at the university of Lille
• Louis Pasteur- French beer company


  asked by a French beer company in 1857 to investigate why alcohol was going sour. examined alcohol under Lister's microscope and saw microbes of a diff shape where the liquid was sour. concluded that germs were causing the beer to go sour
• Louis Pasteur- French Emperor

  in 1863 Pasteur was asked to save the French wine industry as much of it was going sour. he examined the wine and found microbes in it. he heated the wine and this killed the microbes- pasteurisation! he announced his belief that germs in the air were the cause of liquids going sour and maybe even disease
• Louis Pasteur- support of the French government


  in 1864 Louis gained the financial support of the government and conducted several public experiments which successfully showed microbes cause disease. published germ theory
• Louis Pasteur- proving that microbes are dangerous to living organisms


  called to help disease in French silkworm industry. proved worms were killed by a disease called pebrine
• Louis' dead end


  cholera in Paris 1865- Louis' daughter died. he took air samples from ventilators leading from a cholera hospital ward. all he could see were lots of diff microbes. didn't know which was cholera
• impact of germ theory in Britain

  Dr Henry Bastein- 1870s- promoted spontaneous generation. John Tyndall- 1870- gave a lecture linking to germ theory. Joseph Lister's son linked germs to infections he was seeing post-operation
• suspicions over germs as a threat to humans

  scientists could see germs were present in the blood of healthy people
• germ theory overview


  the air contains living organisms, microbes are not evenly distributed in the air, microbes in the air cause decay and disease, microbes can be killed by heating
• factors involved in germ theory

  technology (microscopes, swan-necked flask), individual genius, government
• Robert Koch vs Louis Pasteur

  late 1860s- intense rivalry between Prussia and France. 1870- rivalry developed into war. Prussian victory lead to the unification of all German states into one nation- Germany. Koch was a German surgeon in the Prussian army during the war and grew to hate the French. wanted to contribute more to germ theory than Pasteur
• Koch: 1873-1880


  Koch investigated anthrax and discovered a special bacterium causes it- first time a germ has been identified. he invented agar jelly and a method of staining bacteria so they could be identified, photographed and analysed
• Koch's method for identifying pathogens

  the microbe identified as source of the disease must be present in every case of the disease. the microbe must be taken from a diseased body and grown in a pure culture and then injected into a healthy animal- the same disease must be caused. the microbe must be isolated from the animal and identified as the same original microbe
• Pasteur: 1880


  epidemic of chicken cholera. got a research team & identified the bacterium causing cholera. Chamberland forgot to inoculate chickens over summer so when they were inoculated after summer the germs had weakened over time and the chickens survived the injection and became immune. produced the chicken cholera vaccine.
• Pasteur: 1881 May


  conducted successful public experiment on sheep in rural France. produced vaccination against anthrax
• Koch: 1881-1882


  found specific bacterium for TB- first one that causes disease in humans. did this by staining it so it stood out from other bacteria and human tissue. others in his lab used his methods to discover the germ that causes cholera
• Pasteur: 1885


  developed vaccine for rabies (first vaccine for humans after Jenner & knew why it worked unlike Jenner). tested on dogs then on Joseph Meister (boy bitten by rabid dog). gave him 13 injections over 2 weeks. he survived and was cured.
• germs discovered with Koch's methods

  typhoid-1882, cholera-1883, pneumonia, meningitis
• vaccines developed using Pasteur's methods

  TB-1921, typhoid-1896, tetanus, diptheria
• British gov reaction


  ignored it at first. Koch travelled to Calcutta in 1884 and proved cholera was caused by microbes in water, still ignored by goverment