Robert Koch

Robert Koch (1843-1910), German scientist and Nobel laureate, who founded modern medical bacteriology, isolated several disease-causing bacteria, including those of tuberculosis, and discovered the animal vectors of a number of major diseases.

Born in Klausthal-Zellerfeld, on December 11, 1843, Koch enrolled at the University of Göttingen in 1862, where he studied botany, physics, and mathematics and began his lifelong medical career. After a brief tenure at the Hamburg General Hospital and at an institute for retarded children, he started private practice. His professional activities did not deter him from developing outside interests in archaeology, anthropology, occupational diseases such as lead poisoning, and the newly emerging field of bacteriology.

Koch's first major breakthrough in bacteriology occurred in the 1870s, when he demonstrated that the infectious disease anthrax developed in mice only when the disease-bearing material injected into a mouse's bloodstream contained viable rods or spores of Bacillus anthracis. Koch's isolation of the anthrax bacillus was of momentous import, because this was the first time that the causative agent of an infectious disease had been demonstrated beyond a reasonable doubt. It now became clear that infectious diseases were not caused by mysterious substances but instead by specific microorganisms—in this case, bacteria. Koch also showed how the investigator must work with such microorganisms, how to obtain them from infected animals, how to cultivate them artificially, and how to destroy them. He revealed these observations to the great German pathologist Julius Friedrich Cohnheim and his associates, one of whom was the German bacteriologist Paul Ehrlich, the founder of modern immunology.

In 1880, after completing important work on the bacteriology of wound infections, Koch was appointed government adviser with the Imperial Department of Health in Berlin, where he carried out most of his research for the rest of his career. In 1881 he launched his studies of tuberculosis, and the following year he announced that he had isolated a bacillus that was the causative agent of the dreaded disease. Koch's findings were confirmed by investigators around the world. The discovery led to an improvement in diagnosis by means of finding evidence of the bacilli in bodily excretions, especially sputum.

Koch now focused his attention on cholera, which had reached epidemic levels in India by 1883. Traveling there, he identified the bacillus that caused the disease and found that the bacillus was transmitted to human beings primarily through water. Koch later traveled in Africa, where he studied the causes of insect-borne diseases.

In 1891 Koch became director of Berlin's Institute for Infectious Disorders (the institute now bears his name), which had been organized for specialized medical research, and remained there until he retired in 1904. In 1905 he won the Nobel Prize in physiology or medicine. On May 27, 1910, Koch died at the German health resort of Baden-Baden.