4. Stubbins Ffirth

 Stubbins Ffirth, source Internet

As a doctor training in Philadelphia, Stubbins Ffirth, made hypotheses about yellow fever. He revealed that the disease is not a contagious disease.
Around the 1800s, he still continued his hypothesis by conducting experiments on himself. He poured into an open wound infected blood. He also tried to drink the blood. Ffith did not fall ill, but it was not proved that yellow fever was not contagious. Because then known that transmission occurs by injection into the bloodstream, or through mosquito bites. Source: kapanlagi