430 EXPERIMENT STATION RECORD. 



bacteria which malie available as a source of carbohydrate energy for nitrogen- 

 fixing: bacteria the cellulose material present in the soil. 



Denitrification and nitrogen fixation in cultivated soil, F. S. Marr {Mitt, 

 Landiv. Inst. Breslau, 5 (1910), Xo. 5, pp. 639-656). — This is a report of a 

 series of experiments in denitrification and nitrogen fixation in cultivated soils 

 to which organic matter was added in the form of straw, straw and potassium 

 nitrate, 2 and S per cent sugar solution, and 2 and 8 per cent sugar and potas- 

 sium nitrate. In one series the contents of the vessels were thoi'oughly aerated 

 throughout the experiments ; in the other series no aeration was performed. 

 The results were variable, some vessels showing a loss of nitrogen in the 

 soil, while others showed a gain, indicating in the first instance that denitri- 

 fication was predominant, and in the other nitrogen fixation. 



Biological and chemical studies on nitroso bacteria, G. E. Gage {Centhl. 

 Bakt. ictc], 2. Aht.. il (1910). Xo. 1-3, pp. 7--'t8, di/iiis. //). — A study was made 

 of the activities of P sen do mo nan radicicola as isolated from the soil and grown 

 in symbiosis with Trifolium pratensc, in which the results are given of a large 

 number of experiments on the biology and chemistry of nitroso bacteria as 

 represented by P. radicicola. 



As a result of these experiments it is claimed that P. radicicola can be iso- 

 lated from the soil, carried through inoculation experiments, and recovered in 

 a pure state, and that the weakest strains of this organism may, jjy constantly 

 growing on nitrogen-free media, become extremely virulent cultures capable 

 of considerable fixation of nitrogen. Its greatest biological activities are shown 

 when on nitrogen-free media containing maltose as a source of energy; when 

 grown on carbohydrates containing less than ."> carbon atoms no gum is pi'oduced. 

 In very old cultures, especially on solid media, P. radicicola develops a cell- 

 like membranous structure, but which does not give the cellulose and starch 

 reactions; when inoculated from such cultures into artificial culture solutions 

 it may produce considerable nitrite and nitrate. Sugars as a source of energy 

 accelerate the growth of tho organism and the nitrification. 



The article closes with an extensive bibliography of the literature on nitroso 

 bacteria. 



The action of Marasmius oreades on plant growth, M. Molliard (Bid. Soc. 

 Bot. France, .57 (1910), Xo. I, pp. 6.i-69, pi. 1, pys. 2). — A study is reported 

 on the action of the fungus .1/. oreades on the vegetation within the ring of the 

 advancing fungus and along its periphery, to determine the cause of the de- 

 struction of the plants within the growing zone and the stimulating effect 

 immediately adjacent to it. 



The fungus niycelium is found to reduce greatly the water content of the soil, 

 thus weakening the growth of other plants. Through its action on the humus 

 of the soil the fungus increases the total nitrogen to an injurious amount in 

 the center of the advancing band of growth of the fairy ring. The increased 

 growth made just in advance of the rings and for a short distance within them 

 is attributed to the slight increase in ammonia over tliat occurring normally, 

 resulting in a stimulated growth. 



Annual plants are found to be destroyed by advancing fairy rings, but 

 perennials persist by means of their rhizomes, although they may be tem- 

 porarily affected by the conditions attributed to the fungus. 



Injury to vegetation and animal life by smelter wastes, J. K. Haywood 

 {V. 8. Dept. Afjr.. Bur. Chcni. Bui. 113 (rer.), pp. 63, pis. 8, map 1). — This is 

 a revision of a previous report (E. S. R., 20, p. 28) on this subject, including 

 a second investigation subsequently conducted at Anaconda, Mont. Practically 

 the same conclusions are reached concerning the. extent, character, and range 

 of damage done by these wastes as in the original report. 



