318 PHYSIOLOGY [BoT. Absts., Vol. VIII, 



of compounds of copper and mercury,] Fiihling's Landw. Zeitg. 69: 141-144. 1920. — This is 

 a report of progress in an investigation of the effect of additions of copper and a combination 

 of copper and mercury to urine upon the growth of mustard. A substantial increase is found 

 in the efficiency of the urine with the addition indicated over the untreated urine. — A. T. 

 Wiancko. 



2172. Schmidt, Ernst Willt. Notiz fiber das Vorkommen von Volutin bei Azotobacter 

 chroococcum. [Notes on the occurrence of volutin in Azotobacter chroococcum.] Centraibl. 

 Bakt. II Abt. 50: 44^5. 1920.— The author confirms the former work dtf Fischer that volutin 

 occurs in the older cells of Azotobacter chroococcum and refutes the work of Prazmowski, 

 which did not confirm Fischer's results. — Anthony Berg. 



2173. Wann, Frank B. The fixation of free nitrogen by green plants. Amer. Jour. Bot. 

 8: 1-29. 1 pi., 1 fig. 1921.— Seven species of Chlorophyceae were grown in pure cultures on 

 mineral nutrient agar for periods of from 165 to 297 days. Nitrogen was supplied in the 

 ^oi-m of nitrates in some cases and in the form of urea, glycocoU, asparagine, and ammonium 

 sulphate in others. Some cultures were supplied with glucose and others were not. Analyses 

 for total nitrogen in the cultu*re media were made at the end of the experiment.— When ni- 

 trates were used as a source of nitrogen, and when glucose was also present, all the species 

 showed ability to fix the free nitrogen of the atmosphere, the amounts of fixation representing 

 increases in the total nitrogen content of the culture flasks of from 4 to 54 per cent. A com- 

 parison of these results with those reported by other workers for legume bacteria and Azoto- 

 bacter shows that the algae fix fully as much nitrogen per unit volume of medium as do these 

 bacteria. — Five species were grown in the presence of nitrates but without glucose. A very 

 slight increase in the nitrogen content was foiled in these cases, and the author believes 

 that some fixation took place here. He suggests that the very poor growth made in such 

 cultures may explain the small amount of fixation.— When nitrogenous compounds other than 

 nitrates were supplied as a source of nitrogen, no fixation whatever was obtained, either 

 in the presence or absence of glucose. One case of apparent denitrification is reported.— 

 E. W. Sinnott. 



2174. Whiting, Albert L.,and Warren R. Schoonover. Nitrogen fixation by cow- 

 peas and nodule bacteria. Soil Sci. 10: 411-420. 1920.— Analyses were made of inoculated 

 and uninoculated cowpeas planted in nitrogen-free sand and furnished with nitrogen-free 

 mineral salts and water. A comparison of the nitrogen content of the inoculated plants 

 with that of the seeds or uninoculated plants shows that a marked fixation of nitrogen occurs 

 shortly after the formation of the first true leaf. This in 3 experiments was 19 days after 

 planting. The first appearance of nitrogen fixation was 9 days after planting. At the end 

 of 26 days after planting the nitrogen fixed was 3 times that contained in the original seed. 

 Tests with diphenylamine and brucine, with a-napthylamine sulphanilic acid, and with 

 Nessler's solution failed to show nitrate, nitrite, or ammonia in the inoculated seedlings. 

 Inorganic nitrogen of these forms is not concerned in symbiotic fixation by legumes and nodule 

 bacteria. — W . J . Rabbins. 



METABOLISM (ENZYMES, FERMENTATION) 



2175. Bokorny, Th. Hefeernahrung und Garung. Gibt es eine Hefeentwicklung ohne 

 Zuckervergarung? [Yeast nutrition and fermentation. Can growth of yeast take place without 

 fermentation of sugar?] Centraibl. Bakt. II Abt. 50: 23-33. 1920.— The role of alcoholic 

 fermentation in the life of the yeast plant is discussed. Alcoholic fermentation is not essen- 

 tial, and the yeast plant can grow in the absence of fermentable sugar; fermentation occurs, 

 however, whenever possible, and serves to render the medium unsuitable for the development 

 of competing microorganisms. — M. A. Raines. 



2176. BoRKOWSKi, R. Beitrag zur Kenntnis des Oxydations-vermogens der Wurzeln der 

 hoheren Pflanzen. [The oxidizing powers of the roots of higher plants.] Landw. Versuchssta. 



