Robert Koch

Lore & Background

Koch was born in Clausthal, Germany, the third of thirteen siblings. He excelled academically, teaching himself to read and write before entering school in 1848. In 1862 he entered the University of Göttingen to study natural science, later switching to medicine. After graduating with highest distinction in 1866, he worked as a physician in various hospitals and as a district physician in Wollstein. There, using a microscope given by his wife, he set up a private laboratory and began his microbiology career.

His early research yielded major contributions: he developed techniques for growing bacteria and isolated selected pathogens in pure culture. In 1876 he discovered the anthrax bacillus, impressing Ferdinand Julius Cohn, who helped him publish the finding. Koch later discovered the tuberculosis bacterium in 1882 and the cholera bacterium. He invented the bacterial culture method using agar and glass plates (later developed as the Petri dish by his assistant Julius Richard Petri). He was the first to use the oil immersion lens, condenser, and microphotography in microscopy.

Koch served as government advisor at the Imperial Health Office (1880), senior executive (1882), Director of Hygienic Institute and Professor of hygiene at Berlin University (1885), and director of the Royal Prussian Institute for Infectious Diseases (1891). He discovered tuberculin as a medication for tuberculosis, which proved ineffective but was later used for diagnosis. He died on 27 May 1910.

Reader's Guide

Robert Koch's work established the scientific basis of public health and saved millions of lives. By proving that specific germs cause specific diseases, he directly supported the germ theory of disease and rejected spontaneous generation. His development of bacterial culture methods using agar and glass plates allowed the first laboratory growth of bacteria, revolutionizing microbiology. The four principles known as Koch's postulates, derived from his methods, remain a medical standard for linking pathogens to diseases and influenced later epidemiological criteria such as the Bradford Hill criteria. His discovery of the anthrax bacterium in 1876 is considered the birth of modern bacteriology. The World Health Organization has observed 24 March as World Tuberculosis Day since 1982, commemorating his 1882 announcement of the tuberculosis bacterium. Despite controversy over tuberculin's failure as a treatment, Koch's legacy as a founder of modern medicine and bacteriology endures, with the Robert Koch Institute named after him.

Did You Know?

• Koch taught himself to read and write before entering school in 1848.
• He was the first to use the oil immersion lens, condenser, and microphotography in microscopy.
• His assistant Julius Richard Petri developed the Petri dish based on Koch's bacterial culture method using agar and glass plates.
• The day he announced the discovery of the tuberculosis bacterium, 24 March 1882, is observed as World Tuberculosis Day.