The idea that bad air rising from swamps caused malaria had a good run: at least two and a half millennia, from the time of the ancient Greeks until the mid-19th century. But as Louis Pasteur and Robert Koch popularized the germ theory of infection in the late 1870s, scientists began searching for a bacterial species responsible for the disease. Two scientists even reported having found the culprit, dubbed Bacillus malariae, in the Pontine Marshes near Rome.
But in a military hospital in Algeria, French doctor Charles Louis Alphonse Laveran was taking a close look at a distinctive, granular pigment found in the spleens and other tissues of malaria victims and in the blood of infected people. In November 1880, he trained a light microscope with a maximum magnification of 400x on a drop of fresh blood from a malaria patient. Inside the red blood cells, he saw round, pigment-filled ...
