IO6 MODERN METHODS OF TESTING MILK 



(2) Transferring weighed sample to funnel. Pre- 

 vious to use, each separatory funnel, clean and dry, 

 must be weighed accurately and a record kept of the 

 weight of each. In order to transfer the butter from 

 the beaker to the funnel, the butter in the beaker is 

 melted by warming either by addition of a small 

 amount of boiling water or by putting in a warm place. 

 The melted sample should then be poured without loss 

 into the funnel, which must be held upright. The 

 sides of the beaker are rinsed with a fine stream of hot 

 water, using not more than a teaspoonful each time, 

 and the rinsings poured into the funnel; this treat- 

 ment is repeated until the funnel is full to within one- 

 quarter of an inch of the shoulder. 



(3) Whirling. The separatory funnel is then in- 

 serted in the special socket of the centrifugal, allowing 

 the stem to project through the hole in the bottom, 

 and the handle of the stop-cock through the open side, 

 (the socket always being placed in the centrifuge with 

 the open side facing in the direction in which the wheel 

 revolves, in order to prevent the stop-cock being 

 thrown out and broken). The funnel is whirled one 

 minute at the speed used in testing milk (p. 41). The 

 centrifuge must be kept warm. 



(4) Removal of water. The funnel is taken from 

 the centrifuge and the water is allowed to flow 

 through the stop-cock. Most of the salt and some of 

 the curd are taken out by the water. The rest of the 

 curd and all of the fat remain in the funnel. (Care 

 must be taken to keep the stop-cock always under con- 

 trol, so that it can be closed at the right instant and 

 thus prevent fat running out and consequent loss of 



