11 abr 1920 año - William Park, MD
Descripción:
He worked for the New York City Health Department. He helped develop diptheria immunization and was convinced that pfeiffer's bacillus was the cause of 1918's deaths. Vaccines weren't available till october 17th, 1918Añadido al timeline:
fecha:
11 abr 1920 año
Ahora mismo
~ 105 years ago