Tobacco mosaic disease causes discoloration in young tobacco plants, leading to a unique mosaic pattern on leaves and radically slowing the growth of the adult plants.
Beijerinck subjected the fluids of one of the diseased plants to intense filtration using a fine-grained porcelain filter. He demonstrated that even after such filtration the fluids retained their capacity to infect healthy plants.
This meant that whatever caused tobacco mosaic disease must be smaller than any kind of microbe known at that time.
Beijerinck called the mystery agent a virus the Latin word for poison. Beijerinck published his conclusions about tobacco mosaic virus in 1898.His research won Denmark’s Hansen Prize in 1922.
American chemist Wendell Meredith Stanley created pure crystals of tobacco mosaic virus from an infectious liquid solution in 1935. He found that the virus was not a living organism, since it could be crystallized like salt and yet remain infectious.
Scientists finally became able to see viruses in the 1930s, when electron microscopes were invented.
Discovery of virus by Martinus Beijerinck
