starter activity

Casu marzu is a cheese made from unpasteurised goat’s milk. The cheese is left exposed so that a special cheese fly can lay its eggs on the cheese. The maggots hatch and eat the cheese helping to breakdown the fats and start the fermentation process. The cheese becomes very soft and liquid called lagrima seeps out. The maggots grow to about 8 millimetres long. When disturbed, they can launch themselves for distances up to 15 centimetres. The idea is you eat the cheese, maggots and all!

How did scientists How did scientists discover the cause discover the cause

of disease?of disease?To explore the origins of germ To explore the origins of germ

theory & thetheory & the

work of Louis Pasteurwork of Louis Pasteur

Aims

Your taskYour task

Read p. 128. Find out what a Read p. 128. Find out what a miasma was.miasma was.

‘Miasmists’ toured British cities sniffing out evil-smelling quarters and informing the authorities of the health hazard

What was a ‘miasma’?What was a ‘miasma’?

Common sense told people there was Common sense told people there was a connection between dirt & diseasea connection between dirt & disease

Miasma – poisonous fumes give off by Miasma – poisonous fumes give off by decaying matterdecaying matter

Strong-smelling herbs & spices Strong-smelling herbs & spices countered the effectscountered the effects

Ventilated hospitals improved Ventilated hospitals improved chances of survivalchances of survival

Your taskYour task Reading for gist. Read pp. 128-9 about the Reading for gist. Read pp. 128-9 about the

discovery of micro-organisms. You don’t need discovery of micro-organisms. You don’t need to take notes!to take notes!

What contribution did the following men make What contribution did the following men make to the discovery of the causes of disease?to the discovery of the causes of disease?

Anthony van LeeuwenhoekAnthony van Leeuwenhoek Joseph ListerJoseph Lister Louis PasteurLouis Pasteur

Your taskYour task

Imagine you have been asked to Imagine you have been asked to produce a film explaining the produce a film explaining the discovery of the causes of disease. discovery of the causes of disease. You will be given a template for a You will be given a template for a storyboard. Sketch an image in each storyboard. Sketch an image in each box showing the main stages in the box showing the main stages in the discovery. The first box can provide discovery. The first box can provide the background and the last one can the background and the last one can be the credits!be the credits!

Your taskYour task

Listen to the interview with Robert Listen to the interview with Robert Koch, the scientist who developed Koch, the scientist who developed Pasteur’s experiments into bacteria Pasteur’s experiments into bacteria and developed theories on how they and developed theories on how they caused disease in humans and caused disease in humans and animals.animals.

How did he help the development of How did he help the development of germ theory?germ theory?

What was secret of his success?What was secret of his success?

Koch’s contribution to Koch’s contribution to germ theorygerm theory

Identified the bacterium caused anthraxIdentified the bacterium caused anthrax Other bacteria, e.g. typhoid, TB, cholera Other bacteria, e.g. typhoid, TB, cholera

identified in same wayidentified in same way Developed a technique to cultivate Developed a technique to cultivate

bacteria and used dyes to make them bacteria and used dyes to make them visiblevisible

Secret of his successSecret of his success Built on previous Built on previous

knowledge (Pasteur knowledge (Pasteur & Co.)& Co.)

Repeated Repeated experiments to experiments to check results check results (through 20 (through 20 generations of mice)generations of mice)

Improved testing Improved testing technology, e.g. technology, e.g. developing cultures developing cultures & dyes& dyes Robert Koch, German

scientist in his laboratory

Your taskYour task

Read pp. 130-1 and create a spider Read pp. 130-1 and create a spider diagram identifying the reasons why diagram identifying the reasons why diseases were discovered at this diseases were discovered at this time. Include the following time. Include the following categories: observation, new categories: observation, new technology, medical knowledge, technology, medical knowledge, research teams, individual genius, research teams, individual genius, chance, governments, warfare, other chance, governments, warfare, other reasonsreasons

Reasons for the discovery of Reasons for the discovery of diseasesdiseases

ObservationObservation – P conducted experiments – P conducted experiments using sterile flasks in different locations, using sterile flasks in different locations, identifying that particles in air caused identifying that particles in air caused decaydecay

New technologiesNew technologies – K developed better – K developed better ways of growing bacteria & stains to ways of growing bacteria & stains to identify them; P & K used new identify them; P & K used new microscope developed by Listermicroscope developed by Lister

Medical KnowledgeMedical Knowledge – P called his method – P called his method of immunising chickens against cholera of immunising chickens against cholera ‘vaccination’ after Jenner‘vaccination’ after Jenner

Reasons for the discovery of Reasons for the discovery of diseasesdiseases

Research teamsResearch teams – P used teams of – P used teams of vets & doctorsvets & doctors

Individual geniusIndividual genius – P said, ‘chance – P said, ‘chance favours the mind which is prepared’favours the mind which is prepared’

ChanceChance – chicken cholera solution – chicken cholera solution left exposed showed that germs left exposed showed that germs were weakened by exposure to airwere weakened by exposure to air

GovernmentsGovernments – P received money – P received money from French govtfrom French govt

Warfare Warfare - rivalry between Fr & - rivalry between Fr & Germany spurred on new discoveriesGermany spurred on new discoveries

Other reasonsOther reasons – better – better communications; pressure to communications; pressure to improve agriculture led to anthrax improve agriculture led to anthrax vaccinevaccine

PlenaryPlenary

What do you think was the most What do you think was the most important factor contributing to the important factor contributing to the development of germ theory?development of germ theory?