l6 MILK 



the coils shotild be well dried before extraction is 

 begun. 



Thimble-shaped cases made of fat-free paper 

 are now obtainable and are convenient for holding 

 the absorbent material on which the milk is 

 spread. The fine texture prevents undissolved 

 matter escaping. A case may be used repeatedly. 

 Sour milk may be thinned with ammonium hy- 

 droxid before taking the portion for analysis. 



Babcock Asbestos Method. — This is recom- 

 mended by the A. O. A. C. : Provide a hollow 

 cylinder of perforated sheet metal 60 mm. long 

 and 20 mm. in diameter, closed 5 mm. from one 

 end by a disk of the same material. The per- 

 forations should be about 0.7 mm. in diameter 

 and 0.7 mm. apart. Fill the cylinder loosely with 

 from 1.5 to 2.5 grams of freshly ignited woolly 

 asbestos free from fine or brittle material. 

 Cool in a desiccator and weigh. Introduce a 

 weighed quantity of milk (about 4 grams) and 

 dry at 100°. The cylinder is placed in the ex- 

 traction tube and extracted with ether in the 

 usual way. The ether is evaporated and the fat 

 weighed. The extracted cylinder may be dried 

 at 100° and the fat checked by the loss in weight. 

 A higher degree of accuracy is secured by per- 

 forming the drying operation in hydrogen. 



For thorough extraction, especially with diffi- 

 culty soluble materials and volatile solvents, the 



