Penicillin originated from a fungus. Many fungi that grow on our food, such as the fungus that grows on canteloupes, release very potent antibacterial chemicals.

Penicillin was the first antibiotic used successfully to treat people with life threatening infectious diseases. In 1928 a British scientist, Alexander Fleming, noticed that mould prevented the growth of bacteria in his lab but his curiosity went no further. However the main work of producing an effective antibiotic occured 10 years later by an Australian scientist, Howard Florey, pictured on the right. His dedicated team transformed penicillin from an interesting, scientific observation into a life saving antibiotic.

On Saturday 25 May 1940 Florey tested penicillin on 8 mice which were previously injected with a lethal dose of streptococci bacteria. This was to prove one of the most important medical experiments in history. Of the 8 mice 4 were given penicillin and 4 were used as controls. The next day Florey rushed to his laboratory to find the 4 mice that were given penicillin had recovered while the other 4 were dead.

In Florey's experiment why did he give penicillin to 4 mice and leave the other 4 mice without penicillin?

Of the 8 mice 4 were given penicillin and 4 were used as controls. Wha tis meant by the term control ?

What is an antibiotic?

What is an antiseptic?

How does an antiseptic differ from an antibiotic?

Gangrene is a life threatening infection that figures prominently throughout history.
Under what conditions does it thrive?
What are the symptoms?