Koch greatly improved staining methods; he laid the foundations of the technical procedures employed in bacteriology today. In the above paper he described his method of slide preparation, making films of bacteria on cover-slips and fixing them gently by heat, his methods of staining, and preserving the specimens. He also gave details of his method of photographing bacteria, and reproduced the first photomicrographs of bacteria. In some of his reproductions of photomicrographs the cilia are clearly perceptible.