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Alexander Fleming

Early Life

Alexander Fleming was born in Ayrshire, Scotland in 1881, and was raised on a farm with a large family. Growing up in the country created an interest in studying the world around him.

When he was 13 he moved to London and became a student at Regent Street Polytechnic. He was very interested in medicine from an early age, and did very well in school.


Eventually he began studying medicine, and at the age of 25 he was accepted with a scholarship into St Mary’s Hospital Medical School, a branch of the University of London.

He began working under Sir Almroth Wright, another well-known medical scientist.

Sir Wright, a scientist who studied the immune system and bacterial infections, was conducting research on vaccines.


Fleming’s initial work in his laboratory focused on wound infection, and he earned a gold medal in 1908 for being the University’s highest ranked medical student.

Scientific Discovery

Throughout his work in medicine, Fleming was among the first of Britain’s doctors to prescribe early versions of antibiotics discovered by Paul Ehrlich.

He also assisted the Royal Army Medical Corps during World War I.

war ambulance
Ford Model T Military Field Ambulance from World War I

He studied antiseptic (germ-killer) use on open wounds and was among the first to advise medical staff that it might be safer to use saline solutions for cleaning large open wounds.

He also discovered a naturally produced chemical in the human body that works as a mild antiseptic.


It was his work with this newly discovered chemical that led him to explore antibacterial properties from a variety of sources.

For instance, he decided to research whether mucus form your nose might fight bacteria in a Petri dish, and found that it did indeed.

At the age of 47, Alexander Fleming was studying the flu virus when he found mold in one of his Petri dishes that originally had bacteria growing in it.


Interestingly, none of the bacteria was growing around the mold.

Fleming decided to continue studying this new phenomenon, and referred the active ingredient in the mold as penicillin, after the Latin name for the mold.

As he researched this phenomenon further, he realized that it was the first antibiotic ever discovered.


But, to make this new antibiotic work as a medicine, the active ingredient would need to be purified.

Scientists Howard Florey and Ernst Chain further developed this ingredient so that it could be used as a medication.


Eventually, penicillin became one of the most widely used medications, vitally important in treating many different bacterial infections and saving many lives.

During World War II specifically, it became very useful and popular for the treatment of wounded soldiers.

New York WWI Troops Fight to get into the Fight
Soldiers of the 369th Infantry Regiment man a trench in France during World War I. The Signal Corps photograph collection includes every major aspect of the United States (U.S.) Army involvement in WWI.

Fleming published a large amount of research papers in the study of bacteria, the immune system, and other types of medical uses for antibiotics.

In the same year that he discovered the antibacterial properties of mold, he was given a professor position at his medical school.

Later Years

At age 62 he was elected into the Royal Society, and given a knighthood the following year.


In 1945, the Nobel Prize in Physiology and Medicine was awarded to Alexander Fleming, Howard Florey, and Ernst Chain for their development of penicillin.

In the later years of his life, Fleming spent time lecturing on medicine and scientific discovery, eventually becoming very famous for his work.

Alexander Fleming died at the age of 74 of a heart attack at his home in London in 1955.

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