In 1897, the ___________ bacteriologist Giuseppe Sanarelli (1864–1940) claimed to have isolated the bacterium which causes yellow fever from the blood of patients with the disease. To test his hypothesis, he injected the bacteria into five patients without their consent. The patients all developed yellow fever symptoms and three died. Canadian physician William Osler (1849–1919) and many other physicians sharply criticized Sanarelli's experiments.