286 PHYSIOLOGY [Bot. Absts., Vol. V, 



2185. Zellner, J. Uber die chemische Zusammensetzung der Agave americana L. nebst 

 Bemerkungen uber die Chemie der Succulenten im allgemeinen. [Chemical composition of 

 Agave americana and the chemistry of succulents in general.] Zeitschr. Physiol. Chem. 104: 

 2-10. 1919. 



METABOLISM (NITROGEN RELATIONS) 



2186. Bokorny, T. Notizen uber Harnstoff und einige andere N-Quellen der griinen 

 Pflanzen. [Urea and a few other sources of nitrogen for green plants.] Pfliiger's Arch. Phys- 

 iol. 172:466-496. 1918. 



2187. Conn, H. J., and R. S. Breed. The use of the nitrate-reduction test in character- 

 izing bacteria. New York Agric. Exp. Sta. [Geneva] Tech. Bull. 73. 21 p. 1919.— This is a 

 reprint of an article in: Jour. Bact. 4: 267-290. 1919. — Abstractor. 



2188. Gibbs, W. M. The isolation and study of nitrifying bacteria. Soil Sci. 8: 427-481. 

 4 pi., 1 fig. 1919. — Pure cultures of Nitrosomonas and Nitrobacter isolated from the soil were 

 grown on washed agar or silicic acid gel containing suitable nutrient salts. On plates the 

 colonies were extremely small and required a microscope for their study. Pure cultures of 

 Nitrosomonas and Nitrobacter did not produce visible growth when inoculated into bouillon. 

 Pure cultures of these organisms were maintained in a liquid medium indefinitely. Sodium 

 chloride at a concentration of 1 per cent was very toxic for Nitrosomonas . The soil extract 

 used to prepare nutrient solutions for these organisms did not prove toxic. The thermal 

 death point for Nitrobacter was 56-58°C. and for Nitrosomonas, 53-55°. At 28°C. Nitrobacter 

 in pure culture produced a maximum of 527 mgm. of nitrogen as nitrates per 100 cc. of solution. 

 Nitroso7nonas at 28°C. in pure culture produced a maximum of 218.9 mgm. of nitrogen as 

 nitrites per 100 cc. of solution. — W. J. Robbins. 



2189. Mayer, A., and G. Schaeffer. Extension aux cas des microbes de la notion 

 d'acides amines indispensables. Role de l'arginine et de l'histidine dans la culture du bacille 

 de Koch sur milieux chimiquement definis. [The indispensable amino acids for micrcfirgan- 

 isms. The role of arginine and of histidine in the culture of Koch's bacillus on synthetic 

 media.] Compt. Rend. Soc. Biol. 82: 113-115. 1919. 



2190. Meisenheimer, Jakob. Die stickstoffhaltigen Bestandteile der Hefe. [The nitro- 

 gen constituents of yeast.] Zeitschr. Physiol. Chem. 104: 229-283. 1919. 



2191. Saillard, Emile. Balance de 1'azote pendant la fabrication du sucre. Precipita- 

 tion des matieres albuminoides de la betterave par l'acide sulfureux, les bisulfites et les hydro- 

 sulfites. [The balance of nitrogen during the refining of sugar. Precipitation of the albumi- 

 noids of the beet by sulphurous acid, bisulphites and hydrosulphites.] Compt. Rend. Acad. 

 Sci. Paris 170: 129-130. 1920.— The determination of the relative amounts of nitrogenous 

 compounds present in the sugary extract of the beet at the various steps in the commercial 

 refining of sugar is given. There is also included the effect of various reagents used in the proc- 

 esses in precipitating these nitrogenous compounds. — C. II. and W. K. Farr. 



2192. Waksman, Selman A. Studies in the metabolism of actinomycetes. III. Nitrogen 

 metabolism. Jour. Bact. 5: 1-30. 1920.— The utilization of different nitrogenous compounds 

 by several different species of Actinomycetes and the transformation of these substances due to 

 the action of the organisms are considered. Various nitrogenous compounds were tested, and 

 glycerol or glucose was used principally as the source of carbon. The conclusions reached 

 are : the Actinomycetes do not utilize atmospheric nitrogen ; proteins and amino acids furnish 

 the best sources of nitrogen, amides being utilized to a limited extent; nitrates and nitrites 

 are utilized fairly well; ammonium salts are poor sources of nitrogen if glycerol is used as a 

 source of carbon, but if glucose is used these salts are readily utilized; the production of 

 ammonia from proteins and amino acids is not characteristic of the group, although some 

 may be produced on continued incubation. Pigments are produced by many species when 

 grown in media containing proteins and amino acids. [See also Bot. Absts. 3, Entries 2860, 

 2883.}— Chester A. Darling. 



