Robert Koch's Contribution to Science

Robert Koch (1843-1910) was born in Germany in Clausthal in the Upper Harz Mountains. He appears to be a precocious child, informing his parents at the age of five that he had taught himself to read by looking at newspapers. At school he developed a love of biology, and it was off to the University of Göttingen in 1862 to study medicine.

Robert Koch's contribution to science is enormous. In fact his biographer Thomas D. Brock said "one cannot even imagine how medicine would have developed without Koch." He discovered the causative agents of tuberculosis, anthrax, cholera, and wound infections. And his postulates provided the framework for understanding the relationship between causative microbes and disease.

Koch started his career as a medical doctor in German provincial towns. His interest in microbes was sparked when his wife gave him a microscope for his thirtieth birthday. He created a small laboratory for himself in his flat in Wollstein, and a local outbreak of anthrax in cattle inspired him to study the disease. He had no access to huge libraries or expensive medical equipment, but set out to demonstrate that the anthrax bacillus was the cause of the disease. It had earlier been discovered by Pollender, Rayer and Davaine.

Koch inoculated one set of mice with bacilli from the spleens of animals that had died from the diease, and another set of mice was incoculated with blood from the spleens of healthy animals. The mice with the anthrax bacilli developed anthrax, the others did not. This demonstrated that anthrax bacteria were the causative organisms but Koch wanted to know more. He wondered if the bacteria could cause the disease even if they hadn't come into contact with any animals.

Koch obtained pure cultures and studied them in detail. He found that when conditions were unfavourable to them, such as a low oxygen environment, they produced round spores which protected against adverse conditions. He also found that when conditions become more favourable they grow bacilli again, and can indeed cause anthrax without any previous contact with animals.

Koch's work on anthrax was published in 1876 and gained him widespread fame. However, he continued for several years in his medical practice, and worked on improving his methods for staining, fixing, and photographing bacteria. In 1880 he was appointed to the Imperial Health Bureau in Berlin and his facilities and equipment started to improve. Here he refined methods for culturing bacteria on growth media such as agar which was kept on a special flat dish that had been invented by and named after his colleague Julius Richard Petri.

In 1882 he discovered the bacterium causing tuberculosis (Mycobacterium tuberculosis); tuberculosis was a common cause of death at this time. The following year he was sent to Egypt to investigate the outbreak of cholera in that country, and he successfully identified the vibrio bacterium that causes the disease. He created a set of rules for the control of cholera epidemics and was awarded a prize of 100,000 marks for his work.

Koch received many awards and honours during his career, but despite strenuous efforts, never managed to conquer tuberculosis. Nonetheless, his vast body of work, and the methodologies he developed helped to make medical microbiology a major scientific discipline.

Public domain, originally from National Institutes of Health