198 PHYSIOLOGY [BoT. Absts., Vol. VII, 



fied Detmer's solution. The same was found true when similar material of Bacillus radici- 

 cola was added. Similar results were obtained by use of crude nucleic acid derivatives from 

 peat, but the pure adenine-uracil fraction was much less efficient. Neither the ash of nucleic 

 acid derivatives nor of Azotobacter is effective in producing growth increase. — Paul B. Sears. 



1332. Lampitt, Leslie Hebbert. Nitrogen metabolism in Saccharomyces cerevisiae. 

 Biochem. Jour. 13:459-486. 3 fig. 1919.— The writer considers (1) factors which influence 

 assimilation of nitrogen by yeast; (2) mechanism of the extraction of nitrogen from amino 

 acids by yeast; (3) influence of available amino-acids and sugars on nitrogen assimilation; 

 (4) apparent excretion of nitrogen by yeast. Under (1) he finds that active reproduction may 

 result in a lowering of the nitrogen coefficient and that the final nitrogen coefficient is inde- 

 pendent of the initial one. Under the second heading he finds the amidase described by Effront 

 produces a non-volatile as well as a volatile acid. His third point of attack discloses that 

 fermentative activity stimulates nitrogen assimilation, and desamination may continue after 

 zymatic activity ceases. Excessive zymatic activity does not insure rapid N-assimilation. 

 And fourth, during fermentation, the yeast constantly loses nitrogen to the liquid. Such 

 nitrogen may be used again. An increase in sugar available for fermentation increases the 

 rate of nitrogen excretion.— ^ivo R. Davis. 



1333. Maze, P., Villa, and Lemoigne. Action de la cyanamide et de la dicyanodiamide 

 sur le developpement du mais. [Action of cyanamide and dicyanodiamide on the development 

 of maize.] Compt. Rend. Acad. Sci. Paris 169 : 804^807. 1 fig. 1919.— Experiments in France, 

 Italy and Germany have shown that results from the use of calcium cyanamide are very 

 variable. Certain authors have held that calcium cyanamide has a toxic effect, delaying the 

 germination of seeds, while others hold that dicyanodiamide, a product of the polymerization 

 of cyanamide, is the toxic agent. The effects of cyanamide and dicyanodiamide were tested 

 with purified chemicals in culture media of definite composition. Cyanamide hinders the 

 germination of maize at the concentration of 0.168 grams per liter both when added to solu- 

 tions of nutrient minerals and when added to distilled water; dicyanodiamide on the other 

 hand was found to be without effect. It was further shown that neither of the two substances 

 under consideration s capable of serving as a source of nitrogen for maize. — V. H. Young. 



1334. Maze, P., Vila, and Lemoigne. Transformation de la cyanamide en uree par les 

 microbes du sol. [Transformation of cyanamide into urea by micro-organisms of the soil.] 

 Compt. Rend. Acad. Sci. Paris 169: 921-923. 1919.— A previous note by the authors showed 

 that pure cyanamide is very toxic to higher plants. The authors have isolated from the soil 

 six species of bacteria among which are Bacillus prodigiosus, B. coli, and B. cloacae, which 

 flourish in the presence of cyanamide in the proportion of 1-1000.— Cultures of these bacilli 

 in bouillon were tested for their effect on cyanamide, and it was shown that while B. coli 

 and one of the strains of B. cloacae do not break down cyanamide, the other species break 

 it down with the formation of urea and in the absence of cyanamide urea was not formed. 

 Traces of ammonia were produced in most cases of cyanamide decomposition. Further ex- 

 periments with a miscellaneous collection of bacteria from milk, soil and dung showed that 

 they did not break down cyanamide nor form urea except in the case of certain forms of B. 

 cloacae and B. siibtilis. Penicillium glaucum and two species of yeasts were shown to have 

 the power of breaking down cyanamide and forming urea. The authors conclude that cyana- 

 mide may be transformed into urea by many soil organisms and this transformation should 

 be rapid except in acid soils. — V. H. Young. 



1335. Wann, F. B. The fixation of nitrogen by green plants. Science 51: 247. 1920.— 

 In the experiments recorded here seven species of grass-green algae were used, all except one 

 being isolated from soil and grown in pure culture. The cultures were made in 500 cc. flasks 

 on approximately 150 gm. of accurately weighed mineral nutrient agar. The full nutrient 

 solution contained 0.5 gm. NH4NO3 per liter, and in the various series this source was replaced 

 by (NH4)2S04, Ca(N03)2, asparagin, glycocoll, urea. In all cultures nitrogen as such was 

 present in approximately equal quantities, and each nitrogen source was set up in duplicate 



