Chemical Abstracts 6(7): 877 April 10, 1912
F C Koch

The Utilization of Cellulose as a Source of Energy for the Assimilation of Atmospheric Nitrogen. III. Nitrogen Fixation. Hans Pringsheim. Univ. Berlin. Centr. Bakt. Parasitenk, Abt. II, 23, 300.—Clostridium americanum does not fix atmospheric N in sterilized cellulose mixts. unless other carbohydrates like dextrose, lactose, mannitol or saccharose are present. However, in the presence of cellulose-bacteria the clostridium is able to fix the N and the latter in turn furnishes food for the development of the cellulose-bacteria. The quantity of N fixed in this way is greater than in the usual carbohydrate medium. F. C. Koch.

The Biological Stimulative Action of Natural Humus. Th. Remy And G. Rosing. Bonn-Poppelsdorf. Centr. Bakt. Parasitenk, Abt. II, 30, 349-84.—Azotobacter chroococcum when grown in Beijerinck's mannitol soln. fixes 2 1/2 times as much N when steril soil is added as when no other addition is made or when a steril aq. extract of the steril soil is added. This stimulating action is in part due to the Fe contained in the humus. A colloidal soln. of Fe(OH)3 in saccharose or an Fe silicate acts equally as well as the steril soil. Silicate in the form of "Thomas phosphate" also stimulates the fixation of N. Only part of the Fe found necessary for the optimum conditions is taken up by the bacteria. F. C. Koch.

Nitrogen-fixing Bacteria. VI. The Assimilation of Atmospheric Nitrogen by Thermophile Bacteria. Hans Pringsheim. Univ. Berlin. Centr. Bakt. Parasitenk, Abt. II, 31, 23.—Nitrogen-fixing bacteria from soil require an addition of soil ext. to Winogradsky's nutrient medium in order to develop thereon. Small amts. of Na2HPO4 and MgSO4 also were added to the medium. A fixation of 0.0059 to 0.0116 g. N was noted hi 12 days. For each g. of fermented sugar an assimilation of 0.003 to 0.0062 g. N was found. F. C. K.