No. 3, April, 1921] PHYSIOLOGY 313 



2149. Knudson, Lewis. The secretion of invertase by plant roots. Amer. Jour. Bot. 

 7: 371-379. / fig. 1920.— Reducing sugars frequently appear in culture solutions containing 

 sucrose. In a series of culture experiments with corn and Canada field peas the production 

 of these sugars was studied. Evidence is given that their appearance is not due to the reac- 

 tion of the culture solution; or to the secretion of invertase by the roots (since the amount of 

 reducing sugar is not increased by incubation). The author believes that these sugars are 

 produced in the root and excreted into the culture solution.— £^. W. Sinnott. 



2150. PiEDALLU, AndbJ:, Philippe Malvezin, et Lucien Grandchamp. Sur le traite- 

 ment de la casse bleue des vins. [The treatment of blue cassia of wines.] Compt. Rend. 

 Acad. Sci. Paris 170: 1129-1131. 1920. 



2151. R A VENN- A, C. Sintesi di un peptide dall'acido aspartico cogli enzimi vegetali. [Syn- 

 thesis of a peptide of aspartic acid by vegetable enzymes.] Atti K. Accad. Lincei Roma Rend. 

 (CI. Sci. Fis. Mat. e Nat.) V, 29' : 55-58. 1920.— A mixture of ground spinach foliage, aspara- 

 gine, and water, with toluol as an antiseptic, was kept in an incubator 20 days. From the 

 liquid a yellowish precipitate was thrown down with basic acetate of lead. This was puri- 

 fied and a considerable quantity of oxalic acid separated from it leaving a substance having 

 some properties characteristic of the dipeptid of aspartic acid. Control solutions were com- 

 pared with this. It is held that asparagine may prove to be one of the first steps in the for- 

 mation of proteins in plants.— F. M. Blodgett. 



2152. Ravenna, C. Sintesi di un peptide dell'acido aspartico cogli enzimi vegetali. [The 

 synthesis of an aspartic acid peptide by means of enzymes from vegetable cells.] Gazz. Chim. 

 Ital. 50: 251-255. 1920.— See preceding entry 2151. 



2153. Schoellhorn, Kurt. Sur la fermentation de quelques levures des nectars des 

 plantes d'hiver. [Fermentation produced by certain yeasts obtained from the nectar of winter 

 plants.] Bull. Soc. Bot. Geneve 11: 154-190. 29 fig. 1919.— A physiological study is pre- 

 sented for 12 strains of Torula which were isolated from the nectar of various flowering plants. 

 One of the organisms is described as a new species and assigned to a new genus, N edaromyces 

 cruciatus SchoU. — W. H. Emig. 



ORGANISM AS A WHOLE 



2154. Hall, Ivan C. Practical methods in the purification of obligate anaerobes. Jour. 

 Infect. Diseases 27 : 576-590. 1920.— Attention is called to the failure of some early investiga- 

 tors to secure unquestionably pure cultures of obligate anaerobes. A critical review of the 

 present status of surface culture, deep culture, and microscopic methods is given. Selective 

 enrichment of the medium and the elimination of aerobic contamination through selective 

 heating and selective cultivation, followed by the method of isolation by deep cultivation in 

 glucose agar, is found most practical for the purification of obligate anaerobes.— Selman A. 

 Waksman. 



2155. Pantanelli, E. Influenza della nutrizione e dell'attivita radicale sul colasso e il 

 disseccamento prodotti dal freddo. [Influence of nutrition and root activity on the injury pro- 

 duced by cold.] Atti R. Accad. Lincei Roma Rend. (CI. Sci. Fis. Mat. e Nat.) V, 29': 6&-71. 

 1920.— Chick pea and bean plants growing in pots in fine earth or quartz sand to which had 

 been added various nutrient salts were exposed to low temperatures and compared with 

 check plants. The author concludes that the sufferance of each cell is directly proportional 

 to the outgo of water during cooling. The richness in sugars and other carbohydrates, an 

 abundant supply of phosphates, and a scarcity of autodigestive enzymes enable the plasma 

 to hold more tenaciously to water. Acidity and an abundant phosphate supply in the soil 

 favor recovery while alkalinity and abundance of nitrogen render plants more delicate. 

 Tests were also made to determine the effect of different amounts of soil moisture and the 

 effect of subjecting different parts of the plant to chilling temperatures. It is concluded 



