160 PHYSIOLOGY [BoT. Absts., Vol. IX, 



1015. Nestler, A. Zur Kenntnis des Rhinanthocyans. [Rhinanthocyan.] Ber. Deutsch. 

 Bot. Ges. 38: 117-121. 1920. — The author gives an account of various methods which he 

 employed in extracting and splitting the glucoside, rhinanthin, which is responsible for the 

 production of so-called blue bread from flour made from grain which contains seeds of Alectoro- 

 lophns hirsutiis, Melampijrum arvense, and other rhinanthin-containing seeds. In the author's 

 experiments the glucoside was secured from the former of the 2 plants ment'oned. The blue 

 color of the alcohol-hydrochloric acid extract of the seeds, which is due to the splitting by the 

 acid of the rhinanthin into rhinanthocyan and sugar, changes to orange red or red brown 

 upon addition of potassium or sodium hydroxide. The blue color does not return after sub- 

 sequent addition of acid. Hydrochloric acid splits the rhinanthin more effectively than 

 sulphuric acid, and the decomposition is also brought about by oxalic, citric, lactic, and acetic 

 acids. In the case of blue-bread production, lactic acid rather than acetic acid is responsible 

 for the splitting, since the acetic acid is relatively weak in its ability to bring about the reac- 

 tion. Good extraction media are 70 percent alcohol plus 5 per cent hydrochloric acid, hot 

 alcohol, and hydrochloric acid in distilled water. The colored solution of rhinanthocyan, 

 however secured, undergoes alteration on standing. The color secured by extraction of the 

 seeds with a medium containing acid, and also the green color of chloroform shaken with 

 the colored extract, disappear when these liquids are passed through the ultrafilter of 

 Wolfgang Ostwald. — R. M. Holman. 



1016. Peterson, W. H., and Helen Churchill. The carbohydrate content of the navy 

 bean. Jour. Amer. Chem. Soc. 43: 1180-1185. 1921. — The completeness of the digestion of 

 the carbohydrates of legumes by malt diastase is enhanced by fine grinding. Such interfering 

 substances as cellulose or protein are broken up and starch is exposed to the action of the 

 enzyme. The authors found the iodine test extremely sensitive to small amounts of starch, 

 but they also conclude that substances other than starch might give the iodine test. — /. M. 

 Brannon. 



1017. Peterson, W. H., E. B. Fred, and J. H. Verhulst. The destruction of pentosans 

 in the formation of silage. Jour. Biol. Chem. 46: 329-338. 1921. — The corn fodder examined 

 contained an average of 21.8 per cent of pentosans. During fermentation some of the pento- 

 sans were destroyed. Pentoses or other furfural-yielding substances, soluble in water, were 

 present in the silage throughout the fermentation. The production of these substances 

 is probably due to the action of microorganisms. — G. B. Rigg. 



1018. Shaffer, P. A., and A. F. Hartmann. The iodometric determination of copper 

 and its use in sugar analysis. I. Equilibria in the reaction between copper sulphate 

 and potassium iodide. II. Methods for the determination of reducing sugars in blood, urine, 

 milk and other solutions. Jour. Biol. Chem. 45: 349-3G4, 365-390. 1921. 



1019. Shaw, R. H., and P. A. Wright. A comparative study of the composition of the sun- 

 flower and corn plants at different stages of growth. Jour. Agric. Res. 20: 787-792. 1921. — 

 Chemical composition of sunflower (Helianthus) and corn {Zea mays) at the silage stage differs 

 principally in the amount and character of the carbohydrates. Tables of analyses are given 

 showing total protein, albuminoid protein, reducing sugars, non-reducing sugars, and starch 

 at several different stages of development. — D. Reddick. 



1020. Tottingham, W. E., R. H. Roberts, and S. Lepkovsky. Hemicellulose of apple 

 wood. Jour. Biol. Chem. 45: 407-414. 1921. — Analysis of apple wood from fruiting branches 

 shows a high content of the acid-hydrolyzable material commonly designated as hemicellulose. 

 The alcohol-soluble fraction resulting from partial hydrolysis of this material has been found 

 to contain large amounts of xylose and glucose, with a little galactose. It is suggested that 

 this hydrolyzable material forms a reserve source of carbohydrate in the metabolism of the 

 apple tree. — G. B. Rigg. 



