[The discovery of the tubercle bacillus by Robert Koch: a milestone for 123 years].

The discovery of the tubercle bacillus and its causal relationship to tuberculosis by the general practitioner Robert Koch (1843-1910) in 1882 was truly a revolutionary discovery by a pioneer. This discovery was very well-documented, making use of optical equipment that had just appeared on the market, and was accomplished in his own home without outside support. In spite of the publication of the discovery in a German medical periodical with only local circulation, the entire scientific world quickly became aware of this fundamental discovery. Koch was relieved from his position as a provincial general practitioner and given a position in a scientific institute in Berlin where he later occupied a central position. Also because of his work on anthrax and cholera, he can be considered a founder of medical bacteriology and was justly awarded the Nobel Prize for Medicine in 1905. A shadow was thrown over all this by his misunderstanding about tuberculin, which he erroneously considered to be a potential medicine against tuberculosis.