314 EXPERIMENT STATION EECORD. 



hydrochloric acid and fill to the 1,000 cc. mark. To 25 cc. of the same (repre- 

 senting 0.25 gm. of copper sulphate) add from 10 to 20 cc. of hydrochloric acid 

 (specific gravity 1.125), heat to the boiling point for one minute, and stopper 

 with a rubber which contains two glass tubes which reach half way to the 

 bottom of the flask. Connect one of the tubes with a carbon dioxid generator 

 and allow a strong stream of gas to pass through the flask. Cool, . rapidly 

 rotating the flask, and add 5 cc. of a 10 per cent potassium sulphocyanid solu- 

 tion and two drops of a decinormal iron chlorid solution. Pass a stream of 

 carbon dioxid through a tube inserted in the mixture, and titrate with a deci- 

 normal titanium trichlorid solution until a milky white color is obtained. 



Methods of estimation of carbohydrates. — III, The cupric reducing power 

 of the pentoses — xylose and arabinose, A. J. Daish (Jour. Agr. Sci. [EnglamU, 

 6 (19U), No. 3, pp. 255-262, figs. 2).— Tables are given to show that the reduc- 

 ing power of arabinose and xylose are almost identical. For practical purposes, 

 when working with the unknown pentoses in plant extracts, it is considered 

 probable that no large error will be incurred by taking as the divisor the aver- 

 age value for arabinose and xylose corresponding with the weight of cuprous 

 oxid dealt with. The reducing powers of these two pentoses differ only very 

 slightly from that of dextrose, the divisors for these three sugars for 100 mg. 

 of sugar being, respectively, 2.536, 2.49, and 2.538. See also a previous note 

 (E. S. R., 32, p. 807). 



Estimation of cellulose in flours with a special regard to their degree of 

 grading, L. Lindet {Ann. Falsi f., 7 (1914), No. 66, pp. 160-171).— The method 

 for determining cellulose in noting the extent to which the flour under examina- 

 tion had been bolted is as follows : 



Ten gm. of flour from which the fat has been removed by either benzin or 

 ether is treated in a beaker glass with 400 cc. of hydrochloric acid (specific 

 gravity 1.025), boiled for one-half hour, and to the mixture is added 50 cc. of 

 a 10 per cent solution of aluminum sulphate. The aluminum sulphate is then 

 converted into an hydroxid with ammonia, the precipitated aluminum hydroxid 

 which engulfs the cellulose particles collected on a filter, washed, and trans- 

 ferred from the filter to a flask or conical vessel, sodium carbonate solution 

 (10 gm. per 100 cc. liquid) added gradually, and the mixture heated to 100° 

 C. for one hour. The precipitate is then acidified with hydrochloric acid, made 

 alkaline with ammonia, collected! on a tared filer, and washed with dilute 

 hydrochloric acid. After drying and weighing, the precipitate of aluminum 

 cellulose is incinerated and weighed again. The quantity of ash found is de- 

 ducted from the original weight and calculated as cellulose to 100 gm. of flour. 



Dr. Herramhof s fat tester. — An apparatus for determining fat in cheese, 

 dry milk, cream, etc., in practice, Herramhof {Molk. Ztg. [Rildesheim'], 28 

 (1914), No. 36, pp. 677-679, fig. 1). — ^The apparatus employed consists of two 

 parts, a flask which receives the cheese to be tested and the butyrometer proper, 

 The outer wall of the mouth of the flask and the inner wall of the butyrometer 

 are so ground as to form a sealed joint. The butyrometer is graduated to 0.5 

 per cent. 



In the test 2.5 gm. of cheese is weighed into the flask and 6 cc. of sulphuric 

 acid (specific gravity 1.5) is added. The flask and contents are heated on an 

 asbestos plate until the cheese is completely dissolved, and 16.5 cc. of sulphuric 

 acid (specific gravity 1.5) and 1 cc. of amyl alcohol are added. The buty- 

 lometer attachment is then placed on the flask and the apparatus kept for 

 about one-half minute on the hot plate. After going through the other details 

 of the procedure, the butyrometer attachment with its contents is stoppered 

 with a rubber, whirled in a centrifuge for three minutes, and placed in a 



