In 1928, a Scottish scientist named Alexander Fleming was researching a kind of bacteria called staphylococcus. He conducted experiments with the bacteria in dishes. Fleming was brilliant, but he was messy and absent-minded. When he left his laboratory to go on vacation, instead of cleaning up, he left the bacteria in dishes. When he returned, he noticed that mold had grown in the dishes while he was gone. He could have just thrown the dishes away. Fortunately, instead, he looked at them under a microscope. Fleming found that the area around the mold was free of bacteria. He realized that the dangerous bacteria must have been dissolved by the mold. These dirty dishes led to the discovery of penicillin, the first antibiotic. Today, this life-saving drug is used around the world. Each year there are over 80 million prescriptions written for penicillin in the U.S. alone!