Events on Apr 20
Discovery of Cortisone
The Mayo Clinic announces its discovery of a synthesized hormone, named cortisone, for the treatment of rheumatoid arthritis.
Discovery of Raduim
Marie Curie, Pierre Curie, and Henri Becquerel discover radium.
First Detective Story
The first recognized detective story, Poe's "Murders in the Rue Morgue," is published.