SOILS FERTILIZERS. 121 



The decomposition of silicates by soil bacteria and yeasts, II, K. Bassalik 

 (ZtscJir. Gdnmg.sphysiol., 3 (1913), No. 1, pp. 15-Jf2; abs. in Centbl Bald, [efc], 

 2. AM., 40 (1914), No. 9-10, pp. 193, i94).— Orthoclase, microcliue, oligoclase, 

 labradorile, noplielin, lencite, potash mica, magnesia mica, olivine, aiigite, horn- 

 blend, tourmaline, and apatite were subjected in fine powdered condition to the 

 action of Bacillus extorquens, a crude culture of nitrite bacteria, a crude culture 

 of butyric-acid bacteria {Clostridium pastcurianum), and beer yeast. 



The solvent action of B. extorquens was greatest In the case of nephelin, mag- 

 nesia mica, and augite, of which from 4 to 6 per cent was dissolved while only 

 about 2 per cent was dissolved in the case of the other minerals. The butyric-acid 

 liacteria gave like results, except that they showed a special capacity for decom- 

 posing aitatite. B. extorquens produced in from 100 to 200 days carbon dioxid 

 equivalent to from three-fourths to four-fifths of the total weight of the mineral. 

 The beer yeast produced about twice as much carbon dioxid as B. extorquens, 

 but its solvent action was relatively small. On the other hand the nitrite 

 bacteria, although producing a relatively small amount of acid, showed a com- 

 paratively high solvent power. 



The results indicate that in the solution of phosphorite the organic acids are 

 of special importance. 



A list of roferencos to literature of the subject is given. 



Nitrogen assimilation in the presence of nitrates, II. Pringsheim (Centbl. 

 Bakt. [etc.], 2. Abt., JfO (1914), No. 1-8, pp. 2i-23).— Experiments are reported 

 which showed that with a sufficient supply of energy-producing materials nitro- 

 gen was fixed by Clostridium americanum in the presence of nitrates, although 

 to a less extent. Nitrogen fixation was increased by the presence of Pcmcillium 

 glaucum in the colostrum culture. 



The chemical composition of the cells of Azotobacter chroococcum, W. Ij. 

 Omemanskv and X. O. 8ikber (Hoppc-Seyler's Ztsehr. I'lnjsiol. Clicm., 88 

 (1913), No. 6, pp. 445-459; abs. in Jour. Chem. Soc. [London], 106 (1914), ^^o. 

 616, I, p. 235). — The characteristic dark brown growth of this organism ob- 

 tained in agar cultures containing the usual mineral salts with 2 per cent 

 dextrin after about six days' incubation at 30° C. was dried rapidly at 30° C. 

 and analyzed. The material was found to contain 6.63 per cent of water, 4.16 

 per cent of ash, and 12.92 per cent of protein. 



The nature of the nitrogen-free substance was not determined, but it appeared 

 to belong to the polysaceharids. Among the products of hydrolysis, lysin was 

 found in larger proportion than arginin, with only minute traces of histidin. 



The behavior of soils sterilized by heat, Vogel (Centbl. Bakt. [etc.], 2. Abt., 

 40 (1914), No. 11-13, pp. 280-284).— Sodium nitrate in a sterile 5 per cent solu- 

 tion remained inichanged when added to nnsterilized soils and to soils sterilized 

 for 30 minutes at two atmospheres in the autoclave but was rapidly reduced 

 to nitrite in the sterilized soils when they were inoculated with cultures of 

 denitrifying organisms. Steaming of soils at 100° C. for different periods did 

 not prevent subsequent nitrate reduction. It is concluded that simple steaming 

 of soils effects incomplete sterilization and that nitrate reduction following sup- 

 posed sterilization is due to certain denitrifying organisms which survive the 

 steaming and become active, rather than to chemical agencies. 



Bacteriolog-ical studies of field soils. — III, The effects of barnyard manure, 

 P. E. Brown (Centbl. Bakt. [etc.], 2. Abt., 39 (1913), No. 20-22, pp. 523-5^2).— 

 The author briefly reviews investigations by others, and in continuation of 

 previous experiments (E. S. R., 28, p. 120) reports studies of the efi'ect of treat- 

 ment with barnyard maniu-e on the bacterial activities in loam soil under field 

 conditions, and also on the relation between bacterial activities and actual crop 

 yields. The soil was treated with 8, 12, 16, and 20 tons of manure per acre. 



