How a country doctor's back-room lab pinned anthrax on a single microbe
In the 1870s Robert Koch was a district physician in the small Prussian town of Wollstein, running experiments in a room beside where he examined patients. With cramped, poor equipment he showed in 1876 that anthrax, which kept killing local people and livestock, came from one specific bacterium.
Born on 11 December 1843 in the German town of Clausthal, Koch was the third of thirteen children of a mining engineer, and taught himself to read before starting school. He studied natural science at Göttingen from 1862, switched to medicine, graduated in 1866 and moved through several posts, including a year as a volunteer army surgeon during the Franco-Prussian War, before settling in Wollstein, today Wolsztyn in Poland.
The anthrax puzzle turned on spores. Koch found that the bacillus could form a dormant stage that survived harsh conditions and sprang back to cause disease when circumstances suited it. Ferdinand Cohn at Breslau was impressed enough to help publish the work in 1876, and a paper the following year contained the first photograph ever taken of a bacterium. Linking one microbe to one disease gave hard support to germ theory and undercut spontaneous generation.
Much of his lasting influence lay in technique. He pioneered the oil immersion lens and the condenser, stained bacteria with methylene blue, and tried growing colonies on potato slices and then gelatin, which melts at body temperature. In 1881 his assistant Walther Hesse passed on a tip from his wife, Fanny: use agar, which stays solid when warm. Koch's 1881 methods booklet became known as the Bible of Bacteriology, and a later assistant, Julius Richard Petri, turned his glass plates into the familiar Petri dish.
He went on to identify the causes of tuberculosis and cholera, and his four postulates for tying a pathogen to a disease are still widely used. Not everything worked: tuberculin, which he offered as a tuberculosis cure, failed as a treatment and later found a role in diagnosis instead. The Nobel committee honoured his tuberculosis work in 1905, and he died on 27 May 1910. Since 1982 the World Health Organization has marked 24 March, the day in 1882 he announced the tuberculosis bacterium, as World Tuberculosis Day.
Source: Robert Koch
