. Bacteria in relation to country life. Bacteria. 198 Bacteria in R,elation to Country Life Winogra,dsky showed also that the amount of nitro- gen fixed bears a certain relation to the amount of sugar supplied. In other words, the bacteria employed used the sugar not only as food, but also as fuel, the energy of which was utilized partly for making the free nitrogen of the air to combine with other elements. Winogradsky demonstrated, likewise, that the fixation of nitrogen is discouraged when nitrogenous substances are present in the culture medium. Thus, when salts of Fig. 29. Non-s
. Bacteria in relation to country life. Bacteria. 198 Bacteria in R,elation to Country Life Winogra,dsky showed also that the amount of nitro- gen fixed bears a certain relation to the amount of sugar supplied. In other words, the bacteria employed used the sugar not only as food, but also as fuel, the energy of which was utilized partly for making the free nitrogen of the air to combine with other elements. Winogradsky demonstrated, likewise, that the fixation of nitrogen is discouraged when nitrogenous substances are present in the culture medium. Thus, when salts of Fig. 29. Non-symbiotic nitrogen-fixing bacteria.—Rods, Clostridia, and spores of Clostridium Paatorianum. (Winogradski.) were purposely added, the fixation of free nitrogen de- creased in proportion to the combined nitrogen sup- plied. A point was finally reached when there was practically no fixation of nitrogen by the bacteria. This fact is of great interest in teaching us that the nitrogen- gathering bacteria, like leguminous plants, prefer to employ the nitrogen compounds already at hand, and turn to the atmosphere only when combined nitrogen is not to be had. Clostridium Pastorianum has been isolated also by other investigators. It seems to be widely distributed in cultivated soils, although we are still in ignorance of the. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Lipman, Jacob Goodale, 1874-1939. New York, Macmillan
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Keywords: ., bookcentury1900, bookdecade1910, bookpublishernewyo, bookyear1911
