It seems simple enough today to be able to say that a disease will have a cause, usually an organism; that it will be possible to grow that organism in a laboratory; that the laboratory culture will then be effective in causing the disease again in a healthy animal and that the organism causing the disease will be found to be the same as the original organism.
But it was not as easy in 1882. Pasteur had only recently refuted the theory of spontaneous generation which had come from selective observations such as the presence of maggots in rotting fruit. Educated people were barely starting to do things we often take for granted today, like washing their hands as a way to prevent disease from spreading.
Despite these conditions, Robert Koch built on the discoveries of people like Jenner in the 18th century and Pasteur and others in the 19th century. But it was left to him to discover bacteria as the cause behind cholera, tuberculosis and anthrax. Before Koch, it was thought that tuberculosis was transferred in families, which it was but not genetically. Koch chased cholera in Egypt and India, anthrax in European farmyards and TB in Germany.
Koch, in India 1897
Today is observed as World TB Day as he published his findings on Mycobacterium tuberculosis on this day in 1882. His work on tuberculosis alone led to a Nobel in Physiology and Medicine in 1905. He certainly fulfilled the early promise he had shown by teaching himself to read and write by the age of three.
As the famous pathologist Cohnheim had said about Koch’s discovery of anthrax:
“……this is not the last time that this young Robert Koch will surprise and shame us by the brilliance of his investigations.”