Dimitri Ivanovski

Dimitri Iosifovich Ivanovsky (1864-1920) (alternate spelling: Iwanowsky) was a Russian biologist who was the first to discover viruses (1892).

Ivanovsky studied in the University of St Petersburg in 1887, when he was sent to investigate a disease affecting tobacco and referred to as "wildfire". Three years later, they asked him to look into another disease of tobacco plants, this time raging in the Crimea. He discovered that both diseases were caused by an infinitely minuscule agent capable of permeating porcelain filters, something which bacteria could never do. He described his findings in an article (1892) and a dissertation (1902).