Reprinted from T.D. Brock, Robert Koch: A Life in Medicine and Bacteriology, Science Tech Publishers: Madison, WI, 1988, pg. 51, Fig 6.5

Robert Koch (1843–1910) was a country doctor from the German hinterlands of what is now Poland. He liked to investigate samples from his barnyard animals under a microscope. He went on to become the world's first and one of its greatest bacteriologists, winning the Nobel Prize in 1905. Although famed for his work on tuberculosis and the postulates named after him, his first success came with the discovery of Bacillus anthracis. These drawings, by Koch and his colleague Ferdinand Cohn, detail anthrax from its virulent form (Figures 1, 2), to endospore germination and formation (Figures 3–5), and back to its original form after the spores were injected into frog epithelial cells (Figure 7).¹ These diagrams were the first depiction of a microbe's entire life-cycle.

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