DIRECTIONS FOR MAKING THE BABCOCK TEST 



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The acid measure is filled to the 17.5 c. c. mark with 

 acid, which is then carefully poured into a test bottle 

 containing milk. The bottle should be held in a slightly 

 slanting position so that the acid may flow down its 

 side and not come in contact with the milk too suddenly 

 and thus act upon it unevenly. The acid being heavier 

 than the milk, sinks directly to the bottom of the test bot- 

 tle without mixing with the milk, which floats upon it. 

 The acid and milk should now be thoroughly mixed by 

 being gently shaken with a rotary motion. The mixture 

 becomes quite hot and soon changes to a dark brown color. 



Whirling the Bottles. The test bottles containing the 

 mixture of milk and acid may be placed in the machine 

 directly after the acid is added, or they may be allowed 

 to stand several hours without harm. An even number 

 of bottles should be whirled at the same time, and they 

 should be placed in the wheel in pairs opposite each other. 

 When all the test bottles have been placed in the appara- 

 tus, the cover should be placed upon the jacket and the 

 machine turned at such a rate that the wheel carrying 

 the bottles shall make from 700 to 1,200 revolutions per 

 minute. This motion must be kept up for six or seven 

 minutes. 



Adding Hot Water. As soon as the bottles have been 

 sufficiently whirled, pour in enough hot water to bring 

 the mixture up to the bottom of the neck. Put the bottles 

 into the machine and whirl them again for about three 

 minutes. Pour in enough hot water to bring all the fat 

 up into the neck of the bottle, where it may be measured. 



Measuring the Fat. To measure the fat, take a bottle 

 from its socket, and, holding it in an upright position 



