214 Condensed Milk and Milk Powder 



1905, 9:531) or some similar apparatus and dilute with water in 

 the tube to about 10.5 ex. — or, if preferred, weigh into the tube 10 

 to 11 grams of a 40 per cent, solution of the substance — add \]A c.c. 

 of concentrated ammonium hydroxid (2 c.c. if the sample be sour) 



and mix thoroughly with the milk. Add 

 10 c.c. of 95 per cent, alcohol and mix 

 well. Then add 25 c.c. of washed ethyl 

 ether and shake vigorously for half a 

 minute, then add 25 c.c. of petroleum 

 ether (redistilled slowly at a temperature 

 below 60 degress C. preferably) and 

 shake again for half a minute. Let stand 

 Fig°° 6i. Balance for weighty 20 minutes or until the upper liquid is 



sweetened^condenBed milk _ pract j ca Hy c l ear an d j ts own lower level 



The T&rsion Balance Co. constant. Draw off of the ether solution 

 as much as possible — usually 0.5 to 0.8 c.c. will be left — into a 

 weighed flask through a diminutive quick acting filter, of selected 

 paper. The flask should always be weighed with a similar one as 

 counterpoise. 



"Re-extract the liquid remaining in the tube, this time with 

 only 15 c.c. of each ether, shaking vigorously half a minute with 

 each, and allow to settle. 



"Draw off the clear solution through the small filter into the 

 same flask as before and wash the tip of the spigot, the funnel and 

 the filter with a few c.c. of a mixture of the two ethers in equal parts 

 (previously mixed and free from deposited water). 



"For perfectly exact results the re-extraction must be repeated. 

 This extraction yields usually not more than about a milligram of 

 fat, if the previous ether-fat-solutions have been drawn off, closely 

 — an amount averaging about .02 per cent, on a 4 gram charge. 



"Evaporate the ether slowly on a steam bath, then dry the fat 

 in a boiling water oven until loss of weight ceases. 



"Prove the purity of the fat by dissolving in a little petroleum 

 ether. Should a residue remain, wash, the fat out completely with 

 petroleum ether, dry the residue, weigh, and deduct the weight. 

 (This should not often be necessary.) 



"Finally deduct the weight obtained by blank determination on 

 the chemicals used. 



"By this method practically absolute results can be obtained." 



