191T] AGRICULTtTRAL OHEMISTEY AGEX)TECHNT. 617 



acidified with dilute sulpliuric acid^ axid an excess of sodium bicarbonate added. 

 It is then titrated with twentieth-normal iodiu solution. 



Elxperimental data submitted indicate closely agreeing or somewhat higher 

 results by the proposed procedure when checked against official methods. 



The inadequacy of the ferric basic acetate test for acetates, L. J. Cubtman 

 and B. R. Haeeis (J(yur. Amer. Chcm. Soc, 39 {1911), No. 7, pp. 1S15-1S17).— 

 Data are reported which show that the ferric basic acetate test is not suf- 

 ficiently sensitive and that it does not furnish a means of roughly estimating 

 the amount of acetate present in a solution. 



Gluten, M. Aspts (Liverpool: Offices of " Mining," 1917, pp. 25, figs. 5). — 

 This is a translation, together with some notes, by W. Jago of the oflBdal 

 French method for the estimation of gluten. Some notes on the interpretation 

 of the results of the analysis of flours are also Included. 



The determination of pentoses and of glutose by means of Fehling's solu- 

 tion, H. Pellet {Internal. Sugar Jour., 19 {1917), No. 222, pp. 275, 276).— 

 The reduction of Fehling's solution by pentoses (arabinose and xylose) and by 

 glutose is discussed. 



The Importance of treating the sample with Fehling's solution at from 63 

 to 65* C. and maintaining it at such a temperature for 10 minutes in the de- 

 termination of reducing sugars In impure samples which may not contain either 

 pentoses or glutose is emphasized. In products supposed to contain either 

 pentoses or glutose the heating should be continued for 30 minutes, or else at 

 boiling temperature for 3 or 4 minutes. 



It is indicated that " the organic matter of beet molasses behaves much less 

 actively toward Fehling's solution than that contained in cane molasses." 



The quantitative estimation of dextrose in muscular tissue, R. Hoagland 

 {Jour. Biol. Chem., 31 {1917), No. 1, pp. 67-77). — On account of the reducing 

 action on Fehling's solution, creatinin was found to be an important source 

 of error in the determination of dextrose in muscular tissue. For the removal 

 of creatinin and also as an efl3cient precipitant for other nitrogenous con- 

 stituents of muscular tissue, an excess of phosphotungstic acid was found to 

 yield excellent results. After considerable preliminary work the following 

 method, which has yielded accurate results, was devised: 



One hundred gm. of finely ground muscular tissue previously freed from 

 visible fat and connective tissue is treated in a 600-cc beaker with 200 cc. of 

 distilled water, gradually heated to boiling, and boiled for a few minutes. 

 During the extractions the contents of the beaker must be frequently stirred. 

 After boiling, the insoluble material is allowed to settle and the clear liquid 

 decanted on to the previously prepared asbestos filter in a 4-in. funnel. Fil- 

 tration is carried on by the aid of suction. The residue is again extracted 

 with 150 cc. of hot distilled water as above. The operation is repeated and 

 the residue finally transferred to the filter, washed with hot water, and filtered 

 as dry as possible. 



The contents of the filter flask are transferred to an 800-cc beaker and con- 

 centrated on the steam bath to a volume of about 25 to 30 cc. The concen- 

 trated liquid is then transferred to a 100-cc. volumetric flask, but the volume 

 should not be allowed to exceed 60 to 70 cc. It is cooled to room temperature, 

 from 25 to 30 gm. of phosphotungstic add dissolved in about 25 cc. of water 

 added, shaken thoroughly, and let stand for a short time. The solution is then 

 made to volume, shaken, and either filtered or centrifiigalized to remove the 

 solid matter. The use of the centrifuge is preferable. A portion of the fil- 

 trate is tested for complete predpitation by the addition of dried phospho- 

 tungstic add. If an appreciable precipitate forms, an aliquot portion of the 



