Ferdinand Julius Cohn, a German-Jewish biologist, was one of the "Fathers of Bacteriology" along with Louis Pasteur and Robert Koch. He studied botany at Breslau and Berlin, before returning in 1849 to his roots, as teacher-researcher at the University of Breslau (now Wroclaw, Poland). In 1859 Cohn founded the Institute of Plant Physiology Breslau. He employed his own large compound microscope, made by Simon Plossl of Vienna & Voigtlander Co. Anti-Semitism appears to have hampered his career.

From 1870 Cohn concentrated on bacteriological studies and was the first to accord a separate status to bacteria, viewing them as part of the vegetable kingdom and re-shaping the early classification by Ehrenberg. See CF: 1-2, pointing out that Cohn's initiatives were "misunderstood" and "objected" to. Cohn introduced sterile culture-media, and classified bacteria by shape into four groups: cocci (spherical), bacilli (short rods), spirochaetes (spiral) and treponemes (thread-like). He demonstrated endospore formation in bacilli when their environment became life-threatening: the change being vegetative to dormant. In 1885 he was the Leeuwenhoek Medallist.

Last modified 8 December 2016