16 MILK 
the coils should 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 o.7 mm. in diameter 
ando.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 
