Career
Honl became one of founders of Czechoslovakian microbiology. Under the guidance of Jaroslav Hlava Honl gained his habilitation in bacteriology at Charles University in Prague in 1898. In 1919 he was named head to the new Czechoslovakian Bacteriological Institute (Ústav pro bakteriologii a sérologii Lékařské fakulty Univerzity Karlovy).
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Honl was one of the early researchers of antibiotics.
At the end of the 1890s he isolated a product of Bacterium pyocyaneum (today called Pseudomonas aeruginosa), which was used as medicine (Anginol) from the start of World War I until it was replaced by penicillin after World World War World War II In 1899 he co-founded an institute to treat tuberculosis in Czechoslovakia and was active in this struggle for decades.