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The Germ Theory. Louis Pasteur finally figures out how diseases are spread. Existing Theories. Miasma & Spontaneous Generation Disease carried by foul air Micro-organisms are the result of the process of decay Pus and gangrene mutates into Germs Flies and Maggots provided evidence
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The Germ Theory Louis Pasteur finally figures out how diseases are spread
Existing Theories • Miasma & Spontaneous Generation • Disease carried by foul air • Micro-organisms are the result of the process of decay • Pus and gangrene mutates into Germs • Flies and Maggots provided evidence • Non-life creates living organisms
Micro-Organisms • Leeuwenhoek • Dutch clockmaker • Built an early powerful microscope • Examined everything he could • He kept on noticing small living organisms in everything he examined • In food, water, excreta, plaque • He did not know what function they played
Improved Microscopes • Joseph Lister in the 1830s • Improved lens production allowed Joseph Lister to produce microscopes that could magnify 1,000 times • Any scientist could buy this microscope • Micro-organisms could be studied in more detail
Pasteur’s Germ Theory • Pasteur • A Scientist (not a doctor) • Brewery in France • Asked Pasteur to investigate why some vats of alcohol would go bad • His theory • Germ = Germination • A growing, living organism caused the problem • His solution to the problem was to boil the liquid to kill the germs • Pasteurisation • Applied to milk, beer, wine, vinegar
Pasteur battles Spontaneous Generation Theory • French Academy launches competition to prove or disprove Spontaneous Generation in 1860 • Pasteur devises experiments to show that microbes existed in the air • Copy source 2 page 129
Linking Germs to Disease • “If wine and beer are changed by germs, then the same can and must happen sometimes in men and animals” • French Silk Industry • Asked Pasteur to investigate why their silkworms kept dying. • He discovered that a certain germ was responsible for
Homework Task • Task page 129 • Draw a flow chart to show how germs were linked to disease • Explain why each step was important • What factors helped the scientists at each step.