German medical scientist regarded as the father of bacteriology. He isolated the tuberculosis bacillus and the anthrax virus. Fountain pen signature, 'R. Koch, July 25, 1901,' on a white 2.75 x 1.75 card, matted with a glossy 5 x 6.5 portrait to an overall size of 8.25 x 11.75. In fine condition. RRAuction COA.