122 PHYSIOLOGY [Bot. Absts., Vol. VI, 



853. Dox, Arthur W., and Lester Yoder. Influence of fermentation on the starch con- 

 tent of experimental silage. Jour. Agric. Res. 19: 173-179. 1920. — Starch constitutes about 

 10 per cent of maize at the time of ensiling. Studies of silage at different stages in the fer- 

 mentation process show that changes in aciditj', alcohol, and sugar are entirely independent 

 of the starch content of the ensiled maize, and that the starch content remains constant 

 throughout the process. The granules remain intact, undergoing no detectable physical 

 change. — D. Rcddick. 



854. Effront, Jean. Sur la relation entre l'acroissement des cellules et la production 

 des enzymes. [Relation between cell growth and enzyme production.] Compt. Rend. Soc. 

 Biol. Paris 83: 194-195. 1920. — Experimenting with "top-yeast" in solutions of increasing 

 degrees of alkalinity the author finds that fermentation of the sugar, that is, enzyme produc- 

 tion, occurs at a degree of alkalinity considerably beyond that at which growth or production 

 of new cells takes place. — E. A. Bessey. 



855. Maestrini, D. Contributo alia conoscenza degli enzimi. I: Amilasi dell'orzo ger- 

 mogliato. [Amylase of germinating barley.] Atti R. Accad. Lincei Roma Rend. (CI. Sci. Fis. 

 Mat. e Nat.) 28 2 : 393-394. 1919. — While amylase of germinating barley may be extracted with 

 distilled water it is more active when this is acidified with acetic acid, and the extraction should 

 have a duration of 6 hours. The soluble starch of commerce is strongly split up by this ex- 

 tract even in neutral solution; the other starches are not split if not first reduced to a paste 

 and if not in solutions of a certain acidity. The source of starch does not perceptibly affect 

 the amylolytic activity. Hydrochloric and acetic acid hasten the action in nearly the same 

 manner. Potassium hydroxide acting for ten hours paralyses the amylolytic activity. The 

 invert sugar produced is a maximum at about 45°C, at 50° the amount of invert sugar dimin- 

 ishes, and it is zero at 70°. — F. M. Blodgett. 



856. Simon, Rene. Contribution a letude de la digestion des tissus vegetaux. [The di- 

 gestion of plant tissue.] Actes Soc. Linneenne Bordeaux (Proces-verbaux) 68: 87-98. 1914. 

 [Received May, 1920]. — The progress of pectose digestion was observed by appropriate means 

 in thin sections of roots, leaves, and germinating seeds. After the alteration of the pectose 

 of the middle lamella the cell walls tend to dissociate. The initial stages of digestion and the 

 subsequent transformations of pectose are made visible by first treating thin sections of plant 

 tissue in a dilute acid (1-2 per cent HC1) for 5 minutes. The acid hydrolizes the pectose in 

 all parts of the plant tissue, but the progress of digestion will be more advanced in those 

 parts in which digestion had started before the initial treatment. The plant tissue is next 

 immersed in a saturated aqueous solution of ammonium oxalate or an alkaline salt, and 

 finally, after washing in water, is stained with Ruthenium red. Pectose which remains un- 

 modified will be soluble in water or alkaline solutions and will not be stained. Pectose-pectin, 

 one of the products of digestion, will be insoluble in water and easily colored by basic dyes. — 

 W. H. Emig. 



METABOLISM (RESPIRATION) 



857. Molliard, M. Influence de la reaction du milieu sur la respiration du Sterigmato- 

 cystis nigra. [Influence of the reaction of the culture medium upon the respiration of Sterig- 

 matocystis nigra.] Compt. Rend. Soc. Biol. Paris 83 : 50-51. 1920.— When grown in saccharose 

 solution of varying degrees of acidity (H 2 S0 4 ) or alkalinity (Na 2 C0 3 ) the production of oxalic 

 acid does not appear at an acidity beyond N /50 and steadily increases with the alkalinity to 

 a maximum at 3N /50. Beyond N /12.5 no acid is formed. Allowing for the C0 2 disengaged 

 from the Na 2 C03 by the oxalic acid the amount of this gas set free by respiratory processes 

 increases rapidly as the acidity diminishes from N /10 reaching a maximum at N /50 alkalinity 

 and diminishing slowly to3N /50 and very rapidly thence toN /12.5. The absorption of oxygen 

 parallels this exactly, the respiratory quotient averaging about 0.93. — E. A. Bessey. 



