218 EXPERIMENT STATION RECOED. 



Influence of organic matter on nitrification in impure cultures, A. Karpin- 

 SKr and B. IS'iklewski (Bui. Acad. Svi. Cracovie, 1907, pp. 596-615; abs. in 

 Jour. Vhcm. 8oc. [London], 9J, il908). No. 5U, II, p. 123; Centbl. Bakt. [etc.], 

 2. Abt., 20 (1908), No. 18-20, p. 618; Chem. Zentbl. 1908, I, No. 13, p. 1317).— 

 Small amounts of organic matter such as Is furnished by soil extracts, humates, 

 and acetates, and even peptones and sugar, favored nitrification in mixed 

 cultures. 



On the production of carbon dioxid in cultivated soil, T. Mark (Meded. 

 Proefstat. Oost-Juva, Jf. scr., 1908, No. 38, pp. 503-5^2, charts 3). — Detailed 

 studies of carbon dioxid production in manured and unmanured soil are re- 

 ported. The results in the main substantiate those reported by Stoklasa and 

 Ernest (E. S. R., 18, p. 1024), as showing the very large production of carbon 

 dioxid in cultivated soils. 



On the action of carbon bisulphid and similar substances on the soil, 

 K. Stormer (Centhl. Bakt. [etc], 2. Abt., 20 (1908), No. 8-9, pp. 282-286; abs. in 

 Chcm. Zentbl., 190S, I, No. 10, p. 980). — Experiments with carbon bisulphid, 

 chloroform, ether, benzol, hydrogen peroxid, arsenic, toluol, xylol, phenol, 

 carbol, and cresol are reported. The fact that higher plants were not killed 

 by the amounts of these poisons which were used is explained as due to evap- 

 oration of the volatile poisons and fixation of the metallic poisons. It was 

 found that certain of the organic substances, such as carbol and cresol, were 

 utilized to some extent by the bacteria as a source of carbon, particularly if 

 the substances were not used in too concentrated solution. The assimilation 

 of the carbon was shown by increased production of carbon dioxid. The bene- 

 ficial effect observed in the case of carbon bisulphid is attributed in part to 

 conversion of the sulphur to SOs but mainly to the setting free of nitrogen 

 from the plasma of cells killed by the poison, the nitrogen thus being rendered 

 available for plants. 



A denitrification experiment, H. Fischer (Centbl. Bakt. [etc.], 2. Abt., 20 

 (190S), No. S-9. pp. 256. 257; abs. in Chem. Zentbl., 1908, I, No. 10, p. 981).— 

 The author's observations indicate that continued denitrification in the same 

 medium does not always result in the formation of antibodies which eventually 

 stop the process. He. believes that the checking of denitrification under such 

 conditions is sometimes due to the formation of free sulphur. In the experi- 

 ment which is reported it was found that the addition of citric acid completely 

 prevented denitrification. When, however, the acid was neutralized denitrifica- 

 tion went on normally. The addition of sodium citrate to the cultures proved 

 very favorable to denitrification. The addition of asparagin was found to be 

 unnecessary except in the case of certain denitrifying bacteria w^hich can not 

 live on nitrate nitrogen alone but also require amid nitrogen in order to reduce 

 nitrates. 



The reduction of nitrates, E. Laurent (Rec. Inst. Bot. Univ. Bruxelles, 1907; 

 abs. in Bui. Assoc. Chini. Siicr. et Distill., 25 (1908), No. 8, p. 780).— It is 

 pointed out that under the influence of sunlight nitrates either dry or in solu- 

 tion are reduced to nitrites independently of the influence of the air. Beer 

 yeasts, especially those of Duclaux, reduce nitrates at 20° C. Penicilliuni glati- 

 cum, Mucor racemosus, and similar organisms also have a reducing power. 

 Germinating seeds and various kinds of tissues produce nitrates when air is 

 excluded. 



Note on dialysis of soils, C. V. Garola (Atti 6. Cong. Internaz. Chim. Appl., 

 'f (1906), pp. 562-569, fig. 1). — Verifying Petermann's results it was found 

 that soils yielded to solution in water when sub.1ected to dialysis through parch- 

 ment paper considerable amounts of potash and phosphoric acid, the amounts 



