AGRICULTURAL CHEMISTRY AGROTECHNY. 809 



Estimation of sugar by the biological method, A. J. Kluyveb (Abs. in 

 CentU. Bakt. [e/c], 2. AM., 38 (1913), Xo. 21-25, pp. 648, 649).— In contra- 

 distinctioa to other workers (Prior, K^iuig and Hormaun, and Geelmuyden), 

 the author introduces large quantities of yeast into relatively small amounts 

 (1 to 2 cc.) of sugar solution held in a special form of fermentation saccha- 

 rometer. Within 40 hours the fermentation is finished and from the amount of 

 carbon dioxid produced the amount of sugar fermented is calculated. 



The method is deemed useful for studying carbohydrate metabolism in plants 

 and animals. 



Estimation of iron in presence of organic substances, E. Salkowski 

 {Hoppe-Seyler's Ztschr. Physiol. Chem., 83 (1913), No. 2, pp. 159-164; <Jbs. in 

 Jour. Chem. Soc. [London], 104 (1913), No. 605, II, pp. 248, 249).— This is a 

 critical study of the difficulty experienced in the estimation of iron in oi'ganic 

 substances. " The iron is converted by fusion with a mixture of alkali nitrate 

 and carbonate into oxid, the fused mass dissolved in water, and the iron oxid 

 collected on an ash-free filter. It is advantageous to carry out the washing 

 with a 10 to 15 per cent solution of ammonium nitrate, and finally to fill the 

 filter with alcohol. A further difficulty is often experienced in removing all 

 traces of iron oxid from the platinum dish." 



The method of estimation of iron as ferric phosphate was examined and 

 found to be very unsatisfactory. Washing the ferric phosphate precipitate 

 with ammonium acetate did not remove the difficulties. 



The soluble nitrogenous substances as a factor for judging flours, B. 

 RoussEAUX and M. Sirot (Ann. Chim. Analyt., 18 (1913), No. 6, pp. 224-228). — 

 It sometimes occurs that the I'esults obtained by analyzing flours according 

 to the usual methods (moisture, ash, fat, dry gluten, acidity, and fineness) 

 indicate a good flour, but when the flour is submitted to a practical baking 

 test, it furnishes a bread, etc.. of inferior quality. The author therefore deems 

 it advisable to take into account the total and soluble nitrogenous substances 

 contained in the flour. 



A flour suitable for baking purposes contains a ratio of total to soluble 

 nitrogen of 5.72 : 1 (data obtained from 26 analyses of satisfactory and unsat- 

 isfactory flours). The total nitrogenous substances were determined by 

 Kjeldahl's method in a 2-gm. sample of flour. 



For estimating the soluble nitrogenous substances, mix 10 gm. of flour with 

 150 cc. of water in a 200-cc. flask and then place in a boiling water bath for 

 from 2 to 5 minutes, shaking frequently during the interval. Take away the 

 burner from the water bath, remove the flask, cool, shake, filter, and deter- 

 mine the nitrogen in 50 cc. of the filtrate (2.5 gm. of flour) by Kjeldahl's 

 method. 



The polarimetric determination of starch in rye and wheat flours, Mach 

 (Ahs. in Osterr. TJngar. Ztschr. Zuckerindus. u. Lcmdw., 42 (1913), No. 6, pp. 

 1011, 1012). — The purpose of this work was to determine especially the starch 

 content of feeds, and furthermore, whether typical samples of rye and wheat 

 by-products can be used as a basis for judging the by-products of the industries 

 dealing with these commodities. Seven samples of material were studied in 

 this connection and the Lintner, Lintner-Wenglein. and Ewers methods were 

 used for determining the starch. 



The conclusions reached were that the polarimetric methods are not so 

 refined that they can be called exact and reliable. On the other hand, these 

 methods, especially Ewers' (E. S. R., 21, p. 108) do furnish results which will 

 aid in judging rye and wheat by-products. 



A new method for examining baked goods, A. Schmid (Chem. Ztg., 36 

 (1912), No. 83, p. 796; Mitt. Lehensm. Unterstich. u. Hyg., Schweiz. Osndhtsamt., 



