SOILS FERTILIZERS. 121 



marked than that of the stroiiiiex" acid producer upon the dicalcium aud trical- 

 cium phosphates. These points, with others noticed during the experiments, 

 have led us to believe that, wliile acid is a great factor in dissolving insoluble 

 phosphates, the carbon dioxid liberated from carbohydrates by the gas produc- 

 ing bacteria must not be overlooked as a solvent agent." 



On the activity of bacteria in soils, J. Vogel {IUus. Landw. Ztg., 27 (1907), 

 Vo. 20, pp. 175, 176; abs. in Centbl. Bakt. [etc.], 2. Abt., 20 (1908), No. 10, p. 

 i^99). — This is a general explanation of bacterial activities in the soil and the 

 conditions, especially the supply of humus and other energy-yielding material 

 in the soil, favoring such activities. Humus is not considered a very efficient 

 source of energy for the soil organisms, hence the necessity for increasing the 

 supply of readily available energy-yielding materials in the soil if vigoi'ous 

 activity of the soil organisms is to be promoted. The author thinks it is still 

 an open question whether the beneficial results following black fallow are due 

 to increase of nitrogen or to the setting free of latent plant food in the soil. 

 Reference is also made to the favorable results both as regards increase of 

 yield and nitrogen content obtained in field experiments with leguminous 

 plants (serradella, yellow lupines, and soy beans) inoculated with Hiltuer's 

 pure cultures of root-tubercle bacteria. 



Atmospheric nitrogen, W. J. U. Woolcock (8ci. Amcr. Sup., 65 (1908), No. 

 1678, p. 1^3). — A brief account is given in this article of the results of experi- 

 ments by Professor Bottomley in England on soil inoculation and also on the 

 possibility of the assimilation of free nitrogen by nonleguminous plants. 



Bacteria inoculation in the culture of leguminous plants, J. Simon (Sachs. 

 Landir. Ztschr., 55 (1907), Nos. 33, pp. 877-881; 34, pp. 901-905).— Thifi is a 

 general discussion of this subject and of the relative merits of commercial 

 preparations of root-tubercle bacteria (nitragin, nitroculture, etc.) based in 

 part upon experiments at the Tharand experiment station. 



The assimilation of free nitrogen by micro-organisms, B. Boullaxger 

 (Bui. Inst. Pasteur, 6 (1908), Nos. 1, pp. 1-12; 2, pp. 49-56; 3, pp. 97-101,).— 

 This is a review of investigations and a critical discussion of the present status 

 of knowledge on this subject, including a bibliography of 84 references to the 

 more important investigations. 



Note on de Rossi's article on the organisms which produce the root tuber- 

 cles of leguminous plants, R. Perotti (Malpighia, 21 (1907), No. 4-6, pp. 

 255-262). — The author cites evidence tending to show that other investigators 

 besides de Rossi have isolated specific organisms from the tubercles of legumi- 

 nous plants, and calls attention to the fact that although in earlier publications 

 de Rossi casts doubt upon this point, in later reports (E. S. R., 19, p. 519) he 

 is careful to disclaim any specific denial of such isolation by other investigators. 



Contribution to the knowledge of denitrification processes, H. Kijhl 

 (CentM. Bakt. [etc.], 2. Abt., 20 (1908), No. 8-9, pp. 258-261; ahs. in Chem. 

 ZcnthJ., 1908, I, No. 10, pp. 980, 981). — A series of experiments ai'e reported 

 which show (1) that the activity of denitrifying organisms was greatly 

 increased under anaerobic conditions (covering the culture solutions with oil, 

 paraffin, etc.), (2) the denitrifying power of pure cultures was greatly 

 increased by adding mixed cultures, and (3) that sea slime set up rapid 

 denitrification in culture solutions. 



The construction of manure pits and the preservation of manure, P. Cor- 

 KELirs (Mitt. Dciit. Landw. Geselh, 22 (1907), No. 48, pp. 409-413, figs. 3).— 

 Plans and descriptions are given of manure pits with systems for the collection 

 of the liquid portion and the convenient arrangement of these pits with refer- 

 ence to the cattle stalls and the handling of the manure is explained. 



