CONVENTION OF OFFICIAL AGRICULTURAL CHEMISTS. 277 



Dairy products. — L. L. Van Slyke submitted a report on work by 3 

 chemists in testing methods of examining dairy products, particularly 

 the determination of fat in cheese. 



The following suggestions of the reporter were ado])ted by the con- 

 vention: In sampling, if possible, take a segment of the cheese, cut it 

 into strips, and run through a sausage mill; otherwise take 3 plugs 

 with the sampler, one at the center, one near the outer edge, and one 

 midway between. Use 2 to 5 gm. of cheese in the determination of 

 water and ether extract. 



The methods of determining water and ether extract were slightly 

 modified. In the determination of water the use of other absorbent 

 materials besides sand is now permitted. The modifications in the case 

 of the method for determining fat consist principally in more detailed 

 directions and precautions regarding manipulation, so tliat the extrac- 

 tion may be complete and the extract as free as possible from impurities. 



The following method suggested by the reporter for tlie determina- 

 tion of acid in cheese was made provisional: To 10 gm. of clieese add 

 water at a temperature of 40° C until the volume is 105 cc. Agitate 

 vigorously, filter, and titrate 25 cc. portion with n, normal sodium 

 hydrate, using pheuolphthalein as an indicator. Calculate as lactic 

 acid. 



Methods proposed by the reporter for determiinng casein and albumen 

 in milk were also made i)rovisional. These methods are substantially 

 the same as already published in bulletins of the Division of Chemistry 

 of this Department.^ The other methods for cheese adopted as pro- 

 visional last year were made official. 



The reporters were instructed to investigate methods of detecting 

 filled cheese and preservatives in milk. 



A paper by J. M. Bartlett on "A modification of the Babcock method 

 and apparatus for testing milk and cream" was read, the modifications 

 proposed consisting jDrincipally of (1) filling the bottles with hot water 

 after adding milk and acid before whirling, and (2) graduating the body 

 of the bottles so that no acid measure is needed. 



Fermented and diMilled Hquors. — W. D. Bigelow reported that there 

 had been no cooperative work in this line during the year. On the 

 basis of the studies made by the reporter himself, the following pro- 

 visional methods were recommended and adopted: A modification of 

 Eoese's method for determining fusel oil, the colorimetric determination 

 of aldehyde by means of rosanilin disulphite, and the determination of 

 esters by saponification and titration of the excess of alkali. 



Several instruments recently devised for testing liquors for fusel oil 

 were described by Mr. Bigelow. These were Bromwell's modification 

 of Eoese's apparatus and Traube's capillarimeter and stalagm.ometer. 



' U. S. Dept. Agr., Division of Chemistry Bulletins 38, p. 109; 43, p. 188 (E. S. K., 

 6, p. 185). 



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