240 Testing Milk and Its Products. 



employed (1 oz. potassium chromate dissolved in 100 cc. of water) 

 are added prior to the titration. 



II. The use of silver nitrate tablets for making standard 

 solutions for volumetrie determinations of salt in butter was 

 proposed by Prof. A. Vivian and G. L. Fitch in 1901.' The tab- 

 lets have not-been on the market during late years. 



278a. Shaw's test for fat and salt in butter. R. H. 



Shaw has devised a method for determining the per- 

 centages of fat and salt in the same sample of butter 

 which has considerable merit. For description of this 

 method see Circ. 202, Bur. of Animal Ind., U. S. Dept. 

 of Agriculture. 



Detection op Aetipicial. Butter. 



279. Determination of the specific gravity of the fil- 

 tered butter fat serves as a good preliminary test. A 

 number of practical methods for the detection of artifi- 

 cial butter have been proposed, but they are either 

 worthless for the examination of samples containing a 

 considerable proportion of natural butter, or give satis- 

 factory results only in the hands of experts. The Reich- 

 ert-Meissl method given in detail below is the standard 

 method the world over, and the results obtained by it 

 are accepted in the courts. 



280. Filtering the butter fat. The butter to be ex- 

 amined is placed in a small narrow beaker and kept at 

 60° C. for about two hours. The clear supernatant fat 

 is then filtered through absorbent cotton into a 200 cc. 

 Erlenmeyer flask, taking care that none of the milky 

 lower portion of the contents of the beaker be poured 

 on the filter. In sampling the butter fat, it is poured 



^ Wis. experiment station, report 17, pp. 98-101 ; Hoard's Dairyman, 

 February 15, 1901, "Uniform Salting of Butter." 



