26 EXPERIMENT STATION RECORD. 



(Ann. Bot. [London], 26 (1912), No. 101, pp. 119-128, pis. 2).— A study of the 

 root tubercles of Alnus and Elieagnus proves that they are modified lateral roots 

 and are produced by infection of the root with a race of the nitrogen-fixing 

 organism Pseudomonas radicicoJa. This bacillus enters the root and propagates 

 itself in the cortex of the nodule as a rod-shaped organism. P. radicicola is 

 believed to be a polymorphic organism exhibiting the bacillus and coccus forms. 

 In Elseagnus the bacteria are found mainly in the region immediately behind 

 the growing point, while in Alnus the bacteroidal tissue traverses the entire 

 length of the nodule. The coccus form is believed to be correlated with a 

 scarcity of available carbohydrates and a change of environment, and it is more 

 resistant to the influence of external agencies than the rod-shaped form. The 

 organism was proved to be capable of fixing free atmospheric nitrogen when 

 isolated from the tubercles. 



Nitrogen nutrition of Aspergillus niger, W. Bbenneb (Ber. Dent. Bot. 

 Gesell., 29 (1911), No. 8, iip. Jf79--'i83; ahs. in Jour. Chem. Soc. [London], 101 

 (1912), No. 591, II, p. 77). — Experiments with A. niger in which a large number 

 of forms of nitrogen were used are reported, and it is shown that ammonium 

 lactate, tartrate, succinate, and oxalate, and asparagin were the most suitable 

 compounds, followed by carbamid and the mineral salts of ammonia. In the 

 case of pyridin nitrate, only the nitric nitrogen seemed to be assimilated. Free 

 ammonia, sodium nitrite, ammonium valerate, and potassium cyanid were toxic. 



The role of nitrogen in plant metabolism, J. M. Petkie (Proc. Linn. Soc. 

 N. S. Wales, 36 (1911), pt. 1, pp. 07-1. 'fO, dgm. 1). — In continuation of previous 

 studies (E. S. R., 22, p. 437). a further account is given of the role of nitrogen 

 in plant metabolism. Studies are reported on the distribution of nitrogen in the 

 seeds of Acacia pycnantha, the nitrogen in ripening seeds of Vicia spp., and the 

 occurrence of potassium nitrate in plants. This latter substance, though one of 

 the principal forms in which plants receive their nitrogen from the soil, was 

 found by the author stored as a reserve in considerable quantity in a shrub. 

 Solan dra grandi flora. 



The author believes that in green plants nitrates contribute to the formation 

 of protein, without light, provided that carbohydrates be supplied, and that this 

 change always begins by a reduction of the nitrates through nitrites to ammonia. 

 Instead of the sudden transformation of the nitrate, he thinks it more probable 

 that the enzymic reduction of nitrate to ammonia is the natural one. It is be- 

 lieved that the stages are the formation of ammonia, the production of hydro- 

 cyanic acid from formaldehyde through formic acid, ammonium formate, and 

 formamid, and in the same way the passage of aldehydes in general through 

 their acid amids to nitriles. From the interaction of ammonia, hydrocyanic 

 acid or nitriles, and the various aldehydes, can be produced the amino-acids, 

 and hence the synthesis of proteids. 



Can humus be directly assimilated by the higher plants? M. Molliabd 

 (Compt. Rend. Acad. Sci. [Paris'], lo.', (1912), No. 5, pp. 29 /-^.O'/).— Experi- 

 ments are reported with radishes grown in tubes containing sterilized and un- 

 sterilized soil to which was added ordinary soil humus. The analyses of the 

 dry matter obtained showed in some instances an increase and in others a de- 

 crease of carbon, which must have come from the humus in the culture. The 

 difference, however, was so slight that the author concludes that if humic 

 material is directly assimilable by green plants it is in a very insignificant 

 amount. 



The influence of phytin on seedlings, A. R. Rose (Abs. in Science, n. ser., 

 35 (1912), No. 897. p. 393). — Phytin, which is found almost universally in seeds 

 and is considered to play a significant role in their germination, has been in- 

 vestigated to determine if possible what the influence of the phosphorus com- 



