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| Staining Techniques and Photomicrography |
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Koch constantly endeavored to improve his techniques, particularly with the aim of objectifying his results. He was given valuable assistance by staining techniques which he had first been shown by Carl Weigert in Breslau. He also documented his findings by photographing the microscope images. He summarized his results in the paper entitled “Techniques for the Examination, Conservation and Photography of Bacteria“. This article also appeared in Cohn’s journal.
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Photomicrography apparatus from
Robert Koch’s estate, ca.1880. | Abbe’s illumination apparatus with a two-lens, achromatic condenser from 1872. Bottom of illustration: three-lens condenser. |
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In his research into infectious wound conditions, Koch was confronted with special difficulties in the visualization and detection of the pathogens involved. He overcame these hurdles with the aid of Abbe’s illumination apparatus, homogeneous oil immersion and aniline staining techniques – and with brilliant results.
In the words of Koch himself at the convention of German naturalists and physicians in Kassel in 1878:
“The combination of the suitable staining techniques, Abbe’s condenser and the homogeneous oil systems completely changed the situation. On specimens where no or only a few characteristic bacteria had previously been visible, this new technique surprisingly showed even the smallest forms of bacteria with such clarity and crispness that they were easy to identify and were clearly distinguishable from other stained objects in the specimen.“ The closing words of his lecture: “A specific form of bacterium can be allocated to every disease, and this always remains the same, no matter how often it is transmitted from one animal to another.“ | |
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