Sir Alexander Fleming  (August 6, 1881 – March 11, 1955)

Sir Alexander Fleming (above) was a young bacteriologist when
an accidental discovery led to one of the great developments
of modern medicine on September 28, 1928. Having left a plate
of staphylococcus bacteria uncovered, Fleming noticed that
a mold that had fallen on the culture had killed many of the
bacteria. He identified the mold as penicillium notatum,
similar to the kind found on bread.

In 1929, Fleming introduced his mold by-product called
penicillin to cure bacterial infections.