Robert Koch (1843–1910) was one of the greatest bacteriologists who ever lived. He was born in Klausthal, in what is now Germany, and educated at Göttingen, where he studied medicine before going into practice. His first achievement was to isolate and identify the anthrax bacillus (1876). In 1882 he isolated and identified the tubercle bacillus (Mycobacterium tuberculosis), and in 1883, while leading an expedition to Egypt and India, he identified the bacterium that causes cholera (Vibrio cholerae). In 1885 Koch was appointed professor of hygiene and bacteriology at the University of Berlin, and in 1891 he became director of the Institute for Infectious Diseases in Berlin. He studied bacterial diseases not only in humans but also in animals, and identified, among others, the cause of rinderpest, the lethal and economically important cattle plague of Africa.
His work was facilitated by many of the techniques he and his associates developed to isolate bacteria and grow them on culture media in the laboratory. Koch published many papers and books and fostered the development of a whole generation of bacteriologists and medical scientists in other fields, not only in his native Germany but from many other nations as well. With Jakob Henle he developed the Henle-Koch postulates, four basic criteria that are required for proof that a micro-organism caused a disease: (1) the organism can be isolated in every case of the disease; (2) it can be cultivated in pure culture; (3) cultured organisms can induce the disease in experimental animals; and (4) the organism can be recovered from the infected experimental animals. Robert Koch was awarded the Nobel Prize in medicine in 1905, a fitting capstone to his distinguished career.
JOHN M. LAST