520 EXPERIMENT STATION RECORD. 



He found that when media are inoculated with root tubercles under anaerobic 

 conditions anaerobic bacteria closely resembling the Clostridium pasteurianu))i 

 of Winogradski, and which certainly belong to the butyric acid group, are 

 always produced. The anaerobes of the root tubercles live in contact with 

 aerobic organisms by symbiosis. The best methods of cultivating the organisms 

 are discussed. 



Experiments on the accumulation of nitrogen in forest soils, L. Grandeau 

 (Jour. Ayr. Frat., n. ser.. 13 (1907), Xo. 19, pi). 580, .5Si).— This is a brief note 

 based upon investigations by E. Henry which have already been noted (E. S. R., 

 18, p. 550). 



Fixation of free nitrogen, nitrification, etc. (Jahrcsher. GUrungs-Organ- 

 isincn, 15 (l!>0'i). pp. 395-4-'/7). — Reports of investigations during the year 1904 

 on fixation of free nitrogen, denitrification, nitrification, preservation of manure, 

 and related micro-biological activities are reviewed. 



On the assimilation of free nitrogen, J. Dumont (Sci. Agron., 1 {1906), No. 

 If, pp. 129-l.'tl ; 2 (,1907), No. 1, pp. 1-13). — This is a critical review of the his- 

 tory and present status of scientific investigation relating to symbiotic and non- 

 symbiotic fixation of nitrogen, discussing especially Jamieson's theory and rais- 

 ing a question as to whether symbiotic fixation and assimilation of nitrogen is 

 the only means whereby leguminous plants acquire nitrogen from the air. 



A possible mission of ferments (micro-organisms) in the soil, T. F. Sedg- 

 wick (Intcniat. Siigur Jour., 9 (1907). Xo. 103, pp. S-',3-3Ji8; Estac. Expt. Cana 

 Azucar [Peru]. Bol. J, pp. 11). — The function of micro-organisms in rendering 

 innocuous the toxic substances excreted by the roots of plants and the soil con- 

 ditions suited to this action are treated briefly. 



Studies of the effect of varying amounts of 1 per cent citriowacid on soils well 

 supplied with carbonate of lime are reported from which the following con- 

 clusions and deductions are drawn : 



" If a soil containing carbonate of lime be' treated with citric acid and is still 

 kept alkaline, a fermentation will slowly set up in the soil and solution showing 

 that decomposition is taking place. If the fermentation is allowed to continue 

 long enough, a deposit will be formed which, if olitained on a filter, washed with 

 distilled water and treated with a dilute acid, will give the reaction for carbon- 

 ates. This deposit will contain calcium, iron, phosphoric acid, etc. The liquid 

 from the filtrate will be colorless and clear as water while the original citrate 

 liquid from the soil is strongly yellow on account of the presence of iron. The 

 clear liquid contains acetates, showing the change by fermentation from citrates 

 to acetates. Upon standing for a long time it will not change. It is quite pos- 

 sible that if changes could be made to take place they would result in the final 

 changes to the humus compounds. If the citric acid solution is allowed to re- 

 main on the soil for a number of months the soil will turn to the black of humus 

 soils, showing that the decomposition leads to the formation of the humus com- 

 pounds. 



" The deductions that may be drawn from these experiments and observations 

 are that, for these soils, the compounds in the soil produced by the action of 

 roots and probably other organic materials of the soil are broken up through 

 the agency of growing ferments, so that carbonates are returned to the soil 

 maintaining its alkalinity, and certain food elements in a very soluble form are 

 liberated; that these ferments to develop and cause decomposition must have 

 an alkaline environment ; and that the rapidity of the decomposition is in pro- 

 portion to the activity of the ferment." 



Treatment of soils with carbon bisulphid, B. Heinze (Centbl. Bakt. [etc.], 

 2. Abt., 18 (1907), Nos. 1^, pp. 56-74; 7-9, pp. 246-264; 13-15, pp. 462-4'tO; 

 19-21, pp. 624-634; 24-25, pp. 790-798; abs. in Jour. Chem. Sac. [Landon], 92 



