He accidentally discovered vitamins while researching a neurological disease.
He caught malaria during his early travels, and returned to Europe to dedicate himself fully to scientific research.
He noticed chickens in his laboratory got sick when fed one type of rice and recovered when fed different type of rice, and he theorized that there must be a ingredient that made them sick.
His father, Christiaan Eijkman, was the headmaster of a nearby school.
He won the Nobel Prize for Medicine like the Englishman George Whipple.