706 EXPERIMENT STATION RECORD. 



The estimation of fat in dry milks, B. G. McLellan (Analyst, 33 [1908), No. 

 890, pp. 353-356; (ihs. in .Jour. ,Voc, Chcm. Indus., 27 (1908), No. 18, p. 954).— 

 '■ The fat may be completely extracted by means of ethylic ether of specific 

 gravity 0.720 if 5 gm. of the sample be placed in a cartridge in a Soxhlet ap- 

 paratus, allowed to soak over night in the solvent, extracted during the whole 

 of the next day, again soaked in the solvent over the following night, and ex- 

 tracted an hour or two the next day." 



The estimation of fat in dry milks, H. Droop-Richmond (Analyst, 33 ( 1908), 

 No. 391, pp. 389, 390). — A discussion of the Werner-Schmid and the Riise- 

 Gottlieb methods. The author modities both methods " by extracting the whole 

 of the fat by successive treatment with solvents rather than to take an aliquot 

 part for evaporation and weighing, as this avoids one source of error." The 

 method is given in detail. 



A new method for milk testing, W. M. Doherty (Analyst, 33 (1908), No. 

 388, pp. 273-275). — To see if any relation existed between the ash and other 

 milk solids, the author compared the amount of phosphoric acid with the other 

 solids. The phosphoric acid is fairly constant and does not follow propor- 

 tionally the amount of solids-not-fat. " Beginning from the milk ash properly 

 incinerated the phosphoric acid may be estimated in 10 minutes or even less. 

 ... In no case, using the phosphoric acid method, did actual watering escape 

 detection. ... It would appear that the phosphoric acid method is capable 

 of indicating results nearer the truth than those obtained by the determination 

 of the solids-not-fat." 



The detection of watered milk by means of the refractometer, C. Mai and 

 S. RoTHENFUSSEB (Ztschf. VntcrsucJi. Nahr. u. Genussmtl., 16 {1908), No. 1-2, 

 pp. 7-19; ahs. in Rev. Gen. Lait, 7 (1908), No. 6, p. 138). — This is a review of 

 previous investigations and an account of the results obtained by the authors' 

 use of Ackermanii's method (E. S. R., 18, p. 811). From the examination of 

 5,000 samples the authors believe that the refractometer is a reliable instru- 

 ment for detecting the adulteration of milk, and they have prepared a table by 

 wbich the percentage of watering may be estimated from the amount of re- 

 fraction. Normal milk has a refraction number of 39. If a sample is 36.5 or 

 less it is proof of adulteration. Milk containing 50 per cent of water had a 

 refraction number of 30.9. The percentage of fat does not affect the refractive 

 power, neither does the addition of formaldehyde. 



A simple colorimetric method for the determination of formalin in milk, 

 E. W. T. Jones (Chem. News, 98 (1908), No. 2556, p. 2//7; ahs. in Analyst, 34 

 (1909), No. 394, PP- 22, 23). — The author describes a method by which he has 

 obtained satisfactory results. The operation can be performed in an Jiour or 

 less, and requires only 10 cc. of milk. The reagent used is iirepared from iron 

 wire dissolved in hydrochloric acid, oxidized with nitric acid, and precipitated 

 with ammonia. 



The limits of experimental error in estimating the amount of moisture in 

 butter, A. Schoonjans (Bui. 8oc. CJiim. Bclg., 22 (1908), No. 8-9, pp. 3)2- 

 360). — Since the maximum moisture content of butter is fixed by law in some 

 countries a rapid and accurate method is an important consideration. The 

 methods of Wauters (E. S. R., 18, p. 873) and other investigators, and also the 

 official methods of European countries, are reviewed. 



The author evaporated butter under different conditions. In a sample of 

 butter placed in a paper-covered beaker and heated in an oven in boiling water, 

 the moisture content was estimated at 16.81 per cent. In another sample of the 

 same butter 18.15 per cent of moisture was obtained in an uncovered beaker 

 heated in an oven in air at 115° C. This indicated that exact values were not 

 attained. 



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