In Medical Mysteries and Miracles (Part 1), I told you what the Ancient Greeks thought about disease and anatomy. As you now know, many of these beliefs were passed on for more than a thousand years! You also know about early experiments with anaesthetic and the use of chloroform in the mid 19th century to make people unconscious during surgery.

Now I want to explain a bit about germs and how to avoid them.

If you read Great Discoveries – Marvellous Minds, you’ll remember that English doctor EDWARD JENNER discovered a vaccine to prevent smallpox in 1796. The world had to wait for nearly 90 years before another vaccination was developed against a serious human disease.

It finally arrived in 1885 from the work of a brilliant French chemist and microbiologist called LOUIS PASTEUR.

For thousands of years it was thought that food became bad and then produced creatures like maggots all on its own. This was known as spontaneous generation.

After experimenting with FERMENTATION, Louis Pasteur proved that this was not true.

He discovered that liquids such as milk and wine contain very tiny living creatures called microorganisms – or GERMS. It is these microorganisms that causes liquids to ferment. Pasteur identified that each liquid contains a different type of microorganism and that wine goes sour if it is contaminated with a ‘foreign’ microorganism during fermentation.

Once Louis Pasteur had proved the existence of Germs, he set about finding a way to get rid of them, which was a MASSIVE step forward in medicine.

He realised that he could stop a liquid fermenting by HEATING it to a certain temperature, which killed the micro-organisms. This is known as PASTEURISATION after Louis Pasteur.

Around 1865, the French silkworm industry was in big trouble. The worms had caught a disease and nobody knew how to stop it – until Louis Pasteur came to the rescue!

He identified the germ causing the disease and worked out how to get rid of it. The silkworm industry was saved!

Several years later, helped by his knowledge of the germs that cause illness, Louis Pasteur managed to develop vaccinations to prevent a disease called ANTHRAX in sheep and also chicken CHOLERA.

Pasteur developed a vaccination for RABIES, which is passed to humans by infected dogs. In 1885, he used his vaccine on a 9 year old boy called Joseph Meister who had been badly bitten by a rabid dog. Against the advice of his colleagues, Pasteur gave Joseph a series of injections - and Joseph recovered!

Today, many countries are practically free from rabies due to Pasteur’s vaccination.

So Louis Pasteur had discovered the cause of disease – GERMS. He also knew how disease spreads and how to stop it.

Surgery had been a risky business because, even if a patient survived an operation, there was a very high chance of infection developing afterwards.

Following Pasteur’s findings, an English Surgeon called JOSEPH LISTER set out to find a substance that would kill germs. This meant he could stop wounds becoming infected after surgery.

Lister discovered that wounds could heal without infection if they were wrapped in bandages dipped in carbolic acid, which acted as an ANTISEPTIC. He also sterilised operating theatres with a carbolic spray.

As less wounds were becoming infected, less patients died. In a very short time, antiseptic was used everywhere as a normal part of surgical procedure.

BACTERIA are Germs. As Louis Pasteur discovered, there are germs everywhere, but some germs cause things to go ‘bad’ or people to become ill.

One of the big problems scientists suffered was separating Germs and keeping them separate. A German doctor called ROBERT KOCH found a way to grow bacteria in a solid form instead of a liquid. This made examining bacteria much easier and led to cures for terrible diseases such as TUBERCULOSIS.

Remember Joseph Lister and the use of carbolic acid as an antiseptic? Or how Louis Pasteur proved germs couldn’t survive heat?

There was a small problem – both acid and heat could hurt people!

So it was very important to find a substance that killed bacteria without harming the patient.

In 1928, a bacteriologist called ALEXANDER FLEMING made a very important discovery – by accident!

He left a dish of bacteria uncovered and after a while it became mouldy. He noticed that the mould forming in the dish appeared to be producing a substance that was killing the bacteria. He identified the mould as ‘Penicillium notatum’ so he called the ‘magic’ substance PENICILLIN. It was the first ANTIBIOTIC in the world.

Fleming found his new discovery could kill a variety of bacteria without harming animals or people - but he didn’t know how to produce it.

In fact, the discovery only became usable in the 1940's when Penicillin was isolated and produced by scientists HOWARD FLOREY and ERNST CHAIN.

Aren’t you glad Alexander Fleming didn’t do the washing up?