Ferdinand Julius Cohn (January 24, 1828 – June 25, 1898) was a German biologist.
Cohn was born in Breslau (Wrocław) in the Prussian Province of Silesia. At the age of 10 he suffered hearing impairment. He received a degree in botany in 1847 at the age of nineteen. Cohn was the first to classify bacteria as plants. He also divided bacteria into four groups: Sphaerobacteria, Microbacteria, Desmobacteria, and Spirobacteria. In 1885 he received the Leeuwenhoek Medal.
Cohn is also known for his description of the life cycle of Bacillus and for showing that it changes from a vegetative state to an endospore when subjected to a "hostile" environment (e.g., high heat). Therefore, sterilization by boiling is not effective. It will only kill the bacteria in the vegetative state and the endospores remain viable.
Cohn died in Breslau.
cs:Ferdinand Julius Cohn de:Ferdinand Julius Cohn et:Ferdinand Cohn sk:Ferdinand Julius Cohn Template:Jb1 Template:WH Template:WS