Alexander Fleming

1881–1955 · Scotland · Discoverer of penicillin.

Contribution

In 1928, observed that Penicillium notatum produced a substance that inhibited staphylococci — penicillin, the first broadly useful antibiotic scaffold of the modern era.

Why It Still Matters

Opened the antibiotic age. Also a cautionary tale: discovery alone was not enough — purification and scale-up (Howard Florey, Ernst Chain) made it medicine.

Active Recall

  1. What observation led to penicillin’s discovery?
  2. Why wasn’t Fleming’s discovery immediately a clinical drug?