428 EXPERIMENT STATION RECORD. (Vol.38 



products of disassimllation created by the second (chiefly biityric acid) and 

 maintains the action of the environment (Azotobacter is alkaligenic and the 

 Clostridium acidogeuic). The satellite species may also unfavorably affect the 

 nitrogen-fixing organism, either through products of assimilation or by con- 

 sumption of the carbon compounds needed for nitrogen-fixiug. The energetic 

 fixation of oxygen by the satellite aerobic species creates conditions favorable 

 to the development of C. pasteurianum, but at the same time hinders the growth 

 of the Azotobacter, which is necessarily aerobic. The form endowed with the 

 maximum vitality and at the same time the most common form in which com- 

 bination of the nitrogen-fixing organisms takes place in the upper soil strata 

 is that of symbiosis between the aerobic and anaerobic nitrogen fixers, princi- 

 pally between Azotobacter and C. pasteurianum. In spite of the opposite prop- 

 erties of the two species, their synergetic activity in the upper strata of the 

 soil results in a harmonious mutual development producing the maximum 

 economy in consumption of energetic substances." 



Distribution of nitrogen-fixing- bacteria in Russian soils, V. L. OmelianskiI 

 and M. Solunskov {Arch. Sci. Biol. [Petrograd], 18 {1915), No. 5, pp. J,59-J,82, 

 pis. 3; abs. in Intcrnat. Inst. Ayr. [Rome'\, Internat. Rev. Set. and Pract. Ayr., 

 7 {1916), No. 7, pp. 9Jfl, 9J,2; Jour. 8oc. Chcni. Indus., 36 {1917), No. 1, p. J,0 ; 

 Chem. Abs., 11 {1917), No. 9, p. 1233) .—Studies conducted at the Imperial Insti- 

 tute of Experimental Medicine, I'etrograd, are reported on the occurrence of 

 Clostridium pasteurianum, an anaerobic, nitrogen-fixing bacterium, and Azoto- 

 bacter chrooeoccum, an aerobic, nitrogen-fixing bacterium in soils taken from 

 different depths in 12 different localities of European and Asiatic Russia. 



It was found that " Azotobacter and C pasteurianum occur very widely in 

 soils of different characters and in the most divergent regions of the Empire. 

 In some few cases only the nitrogen-fixing agent was isolated, for instance 

 Azotobacter in the sands of the Kirghiz Steppes and in the peat soils in the 

 north of European Russia (Province of Archangel). The races of Azotobacter 

 and C. pasteurianum isolated in the inquiries are clearly morphologically dis- 

 tinct, especially those of C pasteurianum. In these exiieriments, the two 

 bacteria studied exhibited a different fixing power, weaker in Azotobacter than 

 in C. pasteurianum, but the figures were very close (1 to 8 mg. of nitrogen per 

 gram of suear decomposed)." 



The action of some olyg-odynamic elements on nitrogen-fixing bacteria, 

 C. MoNTANABi {Staz. Spcr. Ayr. Ital., 50 {1917), No. 2, pp. 69-72; abs. in Inter- 

 net. Inst. Ayr. [Rome], Internat. Rev. Sci. and Pract. Ayr., S {1917), No. 6, pp. 

 83S-840). — Two years' experiments are„reiK)rted with cupper, barium, zinc, lead, 

 and arsenic, using a white, siliceous sand which was so treate<l as to obtain 

 the best conditions for nitrification. The elements were added either at the 

 beginning of the experiment, at the moment of inoculation, or after nitrification 

 had set In and developed strongly, at rates of 0.01, 0.05, and 0.1 gm. per 100 

 gm. of sand. 



It was found that " the action of some of the elements varied fairly con- 

 siderably according to whether they were added at the beginning of the experi- 

 ment or when nitrification was already in progress. In the first case, the addi- 

 tion of copper, even in small quantities, of barium, zinc, lead, and arsenic, the 

 latter in larger quantities only, had a marked inhibiting effect. In the second 

 case, however, owing to its vigorous development, the organism was unaffected 

 except by the largest quanties of arsenic and copper. In none of the experi- 

 ments did the various elements, even when added in the smallest quantities, 

 have a stimulative or favorable effect on the development of the organisms. 



