Alexander Fleming was born on a farm in Scotland in the year 1881.When he was thirteen he went to live with his brother, who was a doctor in London.For five years he worked in a shipping office,but he did not stop studying.In 1902,his uncle left him a little money,and that made it possible for Fleming to become a student at the medical school of St Mary's Hospital, a part of London University.

One of the famous doctors who taught the students at Stmary's at that time was Sir Almor Wright,a bacteriologist.He had done a great deal of the most useful research into the work of blood in protecting the body against bacteria.Fleming learnt from him.

During the First World War, Fleming worked as an army doctor in France.He saw large numbers of soldiers die of their wounds because the wounds made it possible for bacteria to work and multiply（繁衍） so quickly that the blood could not deal with them.

After that war Fleming specialised in（专研） bacteriology,and in 1924 he himself became the professor of
bacteriology,and in Hospital.He continued the research for which St Mary's was famous.In particular he was looking for substances which would directly attack harmful bacteria without doing any harm to the body.

In 1928 he was studying the bacteria which caused painful skin disease.In order to find out how to deal with these germs he was growing them on small paltes.One day he noticed a small area of blue-green mould(霉菌) on one of the plates.It would be necessary to grow the bacteria again.He put the mould under his microscope.It was a very common mould.But the microscope showed Fleming something else:the bacteria all round the mould were dead.

Hah, I knew this story.  

Dr Fleming put some of the mould with more bacteria of the same kind.The germs were destroyed.He tried

it on bacteria of other kinds.It stopped the growth of many other harmful germs.He seemed to have

discovered a powerful antibiotic(抗生素；抗菌素).

What was the substance in the mould which killed the germs?Was it possible to isolate it,to prepare it

as a separate substance?Would it harm the human body or any of it?

For years Fleming continued his experiments.He found that the substance was indeed a powerful

antibotic.He was able to isolate.He called it Penicillin,and he showed that it did not harm the

body.But the substance was very hard to control.Fleming was a bacteriologist of very great ability,but

he did not have a specialist's knowledge of chemistry,and particularly of biochemistry.Biochemistry is

the study of the substances in living things.

It was not until 1940 that biochemists were able to find a way of producing penicillin as a powder

with an unchanging character.The reserch which led to this discovery was done at Oxford by Professor

Howard Florey,an Autralian,and Dr Ernest Chain,a German-born scientist.They were helped by Florey's

wife,who was a doctor.

Penicillin has saved lives and prevented suffering all over the world.It was for this reason that the

Nobel Prize was given to Sir Alexander Fleming,Sir Howard Florey and Dr Chain in 1945.But the

discovery of penicillin also showed the way for the discovery of other wonderful substances which

fight disease germs without harming the body. Antibiotics have been found which deal with almost all

known bacteria and many other deadly germs.These include germs which attack animals and others which

prevent the proper growth of plants.

Very many countries showed how much they valued Fleming's work.When he died in 1955 he was honoured in

one more way.His body was laid to rest in St Paul's Cathedral in London.It is a recognition that a man

has served his country or the world extraordinarily well.

(Finish reading it,I know the Penicillin related with the plate experiment.)

Penicillin antibiotics are historically significant as they are the first drugs that were effective against many previously serious diseases.