Fluorescence Microscope Examination of Bacteria in Soil

By the staining of soil with the fluorescent dye acridinorange and examination of the stained soil under the fluorescence microscope, it is possible to observe directly the living bacteria of soil in their autochthonic condition. All humus substances are stained red in color. The bacteria, living on the humus particles, are of green fluorescence and give an excellent contrast against the red background. The bacteria are vitally stained and can be used for culture experiments. Using this method in some soil tests the autochthonic bacteria of soil have been investigated qualitatively and quantitatively.