Question

LOUIS PASTEUR and ROBERT KOCH

Briefly describe the experiments that each person performed to demonstrate the relationship between the arthropod and the disease agent.

Answer 1

Loius Pasteur – 1822 to 1895

Loius Pasteur French chemist discovered the germs in air that caused bad wine, those germs could be seen under the microscope.

He discovered fermentation; Pasteur demonstrated that yeast cause fermentation by producing alcohol from sugar. He also demonstrated that wine became sour because of organism present in wine which produced lactic acid.

• Pasteur developed a method called pasteurisation which involves the boiling and cooling the wine to kill the germs.
• He proved that germ came from air, by tightly covering the liquid germ can be prevented from entering into the wine.
• In the year 1861 he published the germ theory based on his experiments.
• Pasteur examined the blood of healthy people with the blood of infected people; he observed that the infected people have lot of germs in their blood.
• Edward Jenner had developed the process of vaccination against small pox. Pasteur developed vaccination for chicken cholera, diphtheria, anthrax and rabies.
• Pasteur also suggested boiling the surgical instruments before use to kill the germs in it.

Pasteur was one who discovered that there is the link between germs and disease.

Robert Koch – 1843 – 1910:

Robert Koch further in the year 1876 discovered that specific germ cause specific disease.

He discovered bacillus anthracis cause anthrax.

Experiment:

1. Koch extracted the anthrax bacterium from infected sheep.
2. He injected into the mouse and allowed it to grow.
3. He extracted the bacterium from the blood of mouse and cultured it and examined, again injected into the other mouse.
4. He repeated this process for 20 generations of mice before concluding that the bacterium what he isolated Bacillus anthracis caused anthrax.

Koch further in the year 1882 discovered tuberculosis is caused by Mycobacterium tuberculosis.

In the year 1883 he discovered cholera is caused by Vibrio cholera.

He also developed improved methods for staining bacteria.

He also introduced gelatine and agar which can be used as media to grow bacterial colonies.