SOILS FEKTILIZERS. 21 



tion of 1 per cent of dextrose in i)uro cultures increases the activity of the 

 orfianisius. Higher percentages of dextrose, however, injuriously affect the 

 organisms. 



Denitrifying bacteria are abundant in the upper layers of the soil. They 

 are irregularly distributed in the deei)er layers of the soil, but frequently occur 

 abundantly at a depth of 1 meter. The optimum temperature appears to be 

 nearly identical for nitrifying and denitrifying bacteria in mixed cultures. 



The occui-rence and the formation of nitric acid in humus and naoor soils, 

 F. AVeis (Forstl, Foraikjav., 2 {1908), No. 2, pp. 257-296; abs. in Chem. Ztg., 

 33 {1909), No. 18, Repert., p. 79; Zcnthl. Apr. CJwm., 38 {1909), No. 3, pp. IJfO- 

 l'i8). — It is generally stated that on account of deficient nitrification nitric 

 acid does not occur in forest soils rich in humus, but the author found it regu- 

 larly in considerable amounts in Danish forest soils of various kinds, as well 

 as in moor soils. The amount was very variable, but it was found that nitri- 

 fication not only occurred in the warm summer months but also went on 

 ucti\e]y in October and November, as well as in December. 



Nitrification in Transvaal soils, R. D. Watt {Transvaal Ayr. Jour., 7 

 {1909), No. 26, pp. 202-205). — Reference is made to exi)eriments which the 

 author thinks show conclusively that not only are nitrifying bacteria present in 

 abundance in Transvaal soils, but that they are in a state of greater activity 

 than in the soils of temperate countries on account of the higher temperature 

 prevailing. Further studies indicated that while the activity of the organism 

 was retarded by the long winter droughts which occur in Transvaal, the organ- 

 isms were not destroyed but remained in a resting state. The use of manure 

 and of cultivation to produce more favorable conditions for nitrification is dis- 

 cussed and it is shown that in one case a single cultivation of the surface 

 soil resulted in an increase of over 1 per cent in the moisture of the surface 

 layer and in a higher nitrifying power in the cultivated soil. 



Nitrogen fixing bacteria, IV, F. LoHNis and T. Westermann {CentU. 

 Bald, [vtc.^, 2. Aht., 22 (1908), No. 7-10, pp. 23.i-25Jt, pL 1; «?>«• iH' Chcm. Ztg., 

 33 {1909), No. 37, Repert., p. 173). — This article reports the results of compara- 

 tive tests of Azotobacter derived from different sources and isolated in different 

 ways. It also describes a new nitrogen fixing organism. Bacillus danicus, which 

 is classed with B. malabareiisis, isolated from soil from India. See also pre- 

 vious work (E. S. R., 20, p. 621). 



On ammoniacal fermentation, J. Effront {Compt. Rend. Acad. ScL [Paris], 

 l.'i8 {1009), No. //, pp. 238-21,1; ahs. in Rev. 8ci. [Paris], 47 {1909), I, No. 6, 

 p. 188; Jour. Chcm. Soc. [London], 96 {1909), No. 51,7, II, p. 255).— The author 

 shows that ammoniacal fermentation may be produced in two different ways, 

 (1) in a strictly anaerobic medium with a pure culture of butyric ferment, 

 ajid (2) in an aerobic medium with soil. The fermentation produced by inocu- 

 lation with soil ordinarily gives more rapid and complete results, and is a 

 result of symbiotic action of aerobic ferments and the anaerobic butyric ferment. 

 The butyric ferment was isolated and studied. In distillefy refuse it pro- 

 duced ammonia and triniethylamin. Ammoniacal fermentation proceeded at 

 the same rate as the destruction of the dextrose. 



The constant occurrence of the butyric ferment in soils and of evidences of 

 its activity indicates that this organism plays an important part in the trans- 

 formations by which nitrogen derived from the air and that stored in the soil 

 are rendered assimilable for higher ])]ants. 



Fixation of atmospheric nitrogen {Jonr. Dvpf. Ayr. West. Aust.. 77 {1908), 

 No. /, pp. 51,7-550). — This is a translation of an article by T, Schloesing, Jr., 

 already noted (E. S. R., 19, p. 1023). 



