. Chemical testing of milk and cream . t be observed in adding the sulphuric acid, as anexcessive amount of heat is generated and the contents ofthe test bottle may be thrown out. When alkali is used,slightly more acid is required. THE BABCOCK TEST. The Babcock test for fat in dairy products, named for itsinventor, Dr. S. M. Babcock, chief chemist of the Wiscon-sin agricultural experiment station, is based upon thefact that strong ,sulphuric acid will dissolve the serumsolids in milk and set the fat free from its emulsion. Inconducting the test, the charge is placed in a speciallyconstructed t
. Chemical testing of milk and cream . t be observed in adding the sulphuric acid, as anexcessive amount of heat is generated and the contents ofthe test bottle may be thrown out. When alkali is used,slightly more acid is required. THE BABCOCK TEST. The Babcock test for fat in dairy products, named for itsinventor, Dr. S. M. Babcock, chief chemist of the Wiscon-sin agricultural experiment station, is based upon thefact that strong ,sulphuric acid will dissolve the serumsolids in milk and set the fat free from its emulsion. Inconducting the test, the charge is placed in a speciallyconstructed test bottle and mixed with the proper quan- tity of sulphuric acid. The acid performs other functionsthan the simple solution of the serum solids. Much heatis developed by its action, and this causes the fat globulesto lose their individuality and run together, a conditionwhich greatly facilitates the separation from the serum,and this separation is still further accelerated by theincrease in specific gravity of the serum caused by the. f5? Fig. 1.—Old type ofBabcock milk-testbottle. Fig. 2.—Type of Babcock! milk-test bottle conformingto the requirements of theUnited States Bureau ofStandards, and showinggraduations. presence of the heavy sulphuric acid. When the solutionof the serum solids is effected the complete separation ofthe fat and serum is accomplished by whirling in a centri-fuge. The fat is gradually driven into the graduated neckof the bottle and the percentage read directly. Test bottles.—The Babcock-test bottle for milk, as shownin figure 1, consists of a body holding about 50 cubic centi- meters and the neck graduated so that the percentage offat may be read directly. Seventeen and one-half cubiccentimeters are used in the test, and this volume of averagemilk weighs almost exactly 18 grams. At the temperatureat which the bottles are standardized the specific gravityof butter fat is about Two cubic centimeters weightwice , or grams, which is just
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