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Show Iron Ores Formed by Bacteria. Geologists are realizing more fully as they extend their studies the m- vv-' nitude of the work done by plants and animals In building up and tearing dovn parts of the crust of the earth. Even microscopic organisms perform a large part of this work. Pasteur long ago showed us the deadly power of bacteria in disease and their efficiency effi-ciency In promoting fermentation, but their Influence on the fertility of soils and their work In expediting rock decay de-cay are still subjects of scleutlflo study. |