How Penicillin was Discovered
Penicillin was
discovered by complete accident in 1928 by Alexander Fleming, a medical
scientist. Fleming was actually studying the different strains of staphylococci
(a bacteria which causes various infections), so he had germs growing in
numerous petri dishes. He
added a layer of agar jelly on the bottom of each
dish; this jelly would then cause the bacteria to multiply, as it was the food
for bacteria. Eventually, this bacteria would develop into a spot you could see
without a microscope.
Like many other
scientists, Fleming had difficulty keeping germs from the air out of his
bacteria cultures, and noticed this in particular in one sample. As he was
looking at his samples, he noticed something important in one of them: one of
his cultures had become
contaminated by some kind of mold from the air. This
mold, now a large spot, had a radius all around it where there was no
staphylococci bacteria left. The mold had cleared the zone of bacteria
surrounding it and looked like it was secreting a toxin which ate up all of the
germs in its path.
Fleming immediately set to studying and growing more of what eventually became
penicillium notatum, and discovered that it belonged to the same family of molds
as you find on stale bread or decayed fruit. He also found that it stopped the
growth of most common disease germs. Sometimes, it would completely dissolve the
germs.