534 EXPERIMENT STATION RECORD. 



liarts of the United States, of the rehxtion of lime, character of soil solution, 

 heavy inoculation, aeration, and associative action of bacteria on the etliciency 

 of legume inoculation. The results are thus summarized: 



"(1) Lime is of decided benefit in obtaining successful inoculations of legumes 

 in some soils. These soils often show an acid reaction to litmus. 



"(2) Soil extracts serving as culture media often indicate the probable suc- 

 cess of inoculating a leguminous crop. This, however, may not always hold 

 true. 



"(3) At least during the first season's growth no general cross-iuoculation 

 takes place. Bacteria from one host may, however, inoculate a physiologically 

 related species. 



"(4) Heav.v inoculation by a pure culture increases nodule formation if the 

 soil solution is enriched by the excess of culture medium : however, in a 

 favorable soil a light inoculation well distrilnited is as effective. 



"(5) Thorough aeration is favorable to nodule formation. 



"(G) Whether in a synthetic medium or a natural soil solvition, the functions 

 of a bacterium are influenced by the associative or competitive action of the 

 various groups of organisms with which it comes in contact, as well as by the 

 nature of the culture material." 



Experiments with nitrogen-assimilating bacteria, A. Bruttini (Bol. Quiiid. 

 Soc. Agr. Ital., 11 (1906), No. 18, pp. 658-66',) .—The work of other investiga- 

 tors on this subject is reviewed, and experiments by the author with jNIoore'.^ 

 cultures are reported. These show that while the cultures were effective when 

 the soil was not naturall.v inoculated, so few cultivated Italian soils are in this 

 condition as to render the practical value of artificial inoculation doubtful. 



On some new nitrogen bacteria with autotrophic habits of life, II. Kaserer 

 (ZtscJir. Aiic/ew. Chciii., If) (1906). No. J,0. p. 16S1).— Thin is a brief note on a 

 paper on this suliject presented at the recent meeting of the German Associa- 

 tion of Naturalists and Thysicians. 



The author isolated and describes two organisms which oxidize ammonia com- 

 pounds. The first, to which the name Bacillus iiitrator is given, transforms 

 ammonia compounds directly into nitrate without the intermediate formation 

 of nitrite; the other, BaciUiis (izotofiiiorcsccits. oxidizes ammonia, setting free 

 nitrogen without the intermediate formation of either nitrite or nitrate. 



On the chemical processes involved in the assimilation of elementary 

 nitrogen by Azotobacter and Radiobacter, ,1. Stoklasa (Zfschr. To: Dent. 

 Zuckerindus.,. 1906. No. 608. pp. ' 815-825). — Culture experiments with these 

 organisms, singly and combined in various culture media to determine their 

 capacity for fixing free nitrogen and the conditions which favor this process are 

 reported. In a medium containing 20 gm. of mannite and 0.5 gm. of potassium 

 phosphate per liter Azotobacter assimilated 7.5 mg. of nitrogen per liter in 

 10 days, 90 mg. in 15 days, and 125 mg. in 20 days. Radiobacter cultures 

 show^ed practically no gain in nitrogen, and mixtures of the two organisms 

 showed less gain than Azotobacter alone. Glucose proved a better source of 

 carbon than mannite, ])rovided a little calcium or sodium carbonate was added 

 to the medium. In a glucose medium Azotobacter fixed ISO mg. of nitrogen 

 per liter in 15 days, in which time the glucose was entirely used up. On the 

 average 165 gm. of glucose was required for 1 gm. of nitrogen assimilated. No 

 soluble nitrogen compounds were formed in the cultures. The bacterial mass 

 contained 10.2 per cent total nitrogen and 8.6 per cent i)ure ash, the latter con- 

 taining 62.35 to 58 per cent of phosphoric acid. The nitrogen and phosphorus 

 in the bacterial mass was mainly in the form of nucleo-proteid and lecithin. 

 Measurements of the carbon dioxid evolved showed a very large evolution of 

 this gas, the highest jiroduction being observed at from the fourth to the sixth 



