528 EXPERIMENT STATION RECORD. 



In discussing the results tlie autlior states that tliere is sufficient evidence 

 to connect the galvanotropic curvatures with those of a chemotropic cliaracter. 

 the chemical stimuli being the acid and alkaline ions formed during electrolysis. 

 This is supported by the fact that acids and alkalis are formed in appreciable 

 quantities at the places where the positive and negative electrodes touch the 

 roots. Similar curvatures to galvanotropic ones are produced by acids and 

 alkalis placed on the sensitive zone of the root. If a piece of root tissue under 

 a positive or negative electrode be cut out and applied to another root, the latter 

 curves to the acid or alkaline tissue. Acids and alkalis applied to the sensitive 

 zone of roots produce injuries similar to those produced by an electric current. 



When an electrode is placed against the apex and another some distance 

 beyond the elongating zone of the root, there is no curvature, as the acid or 

 alkali is produced in the root cap and by diffusion affects the sensitive zone in 

 all directions. 



When nonpolarizable electrodes are used with a strength of current sufficient 

 to produce a curvature if applied by polarizable electrodes, no curvature takes 

 place. 



The nodule organism of the Leguminosse, F. C. Harrison and B. Barlow 

 (Proc. and Trans. Roy. Soc. Canada, 2. ser., 12 {1906), pt. 1, Sec. IV, pp. 157- 

 287, pi ft. 26). — The results are given of a 2 years' study with the nodule organ- 

 ism of Leguminoste, in which the authors describe their experiments in the 

 isolation, cultivation, identitication, and c<mimercial application of the organism. 



About .30 S]>ecies of Legumlnosiv belonging to the suborder Papilionaceie were 

 examined and nodules found on all, with the exception of the chick-pea and 

 (lalega officinalis, on wliich no bacteria were found. No nodules were found on 

 the roots of fiymnoeladus, Gleditschia, or Cercis canadensis belonging to the 

 suborder Cjesalpinese, but mycorrhiza were present in all cases. 



In cultivating the organism tlie authors found that a medium composed of 

 wood ashes, sugar, and agar-agar furnished an excellent medium for growth. 

 The morphology of the bacteria taken directly from the nodules was found to 

 vary with the species of plant, condition of infection and growth, age and size 

 of the nodule, and the portion of the nodule examined. In plants belonging to 

 the tribes Pliaseoleae, Hedysareie, and Genistete, the bacteria were mostly small 

 rods with comparatively few branching and irregular cells. In plants of the 

 tribes Trifolia* and Viciejie, branching in irregular forms prevailed. 



The viability of Pseudomonas radicicola from different plants was tested, the 

 growth taking place on ash-maltose-agar, and while the limit of viability is not 

 yet known, the organism will probably live more than two years on favorable 

 agar and in favorable liquid media.- 



Accounts are given of the prepax'ation of nitro-cultures together with the 

 results of experiments in their use. It was found that the material could be . 

 prepared and distributed at a cost not exceeding 25 cts. an acre as compared 

 with $2 or more per acre charged by some commercial firms. In tests of the 

 material distributed, 91 out of the 134 of which reports were received, were 

 successful and showed an increased growth of crop which is attributed to the 

 nitrogen-assimilating organism. 



The use of phytin as a source of phosphorus for some of the lower plants, 

 A. Berthelot (Compt. Rend. Soc. Biol. [Paris], 63 {1!)07), No. 26, pp. 192^ 

 19Jf). — A brief account is given of experiments with yeasts, bacteria, fungi, and 

 alg*, in which phytin was used as a source of phosphorus in the culture media. 

 According to the author, phytin occurs in seeds, tubers, and rhizomes in com- 

 bination with calcium and magnesium, and is an important reserve material for 

 the development of the embryo and the formation of new tissues in plants. 



