14 MILK 
with hydrofluoric acid). The filter is added to 
the residue, the whole ashed, the filtrate then 
added, and the liquid evaporated carefully to 
dryness. The ash of normal milk is about 0.7% 
and faintly alkaline. A marked degree of alka- 
linity and effervescence with hydrochloric acid 
will suggest the addition of a carbonate. 
The method of the A. O. A.C. is as follows: In 
a weighed dish put 20 c.c. of milk from a weighing 
bottle; add 6 c.c. of nitric acid, evaporate to 
dryness, and burn at a low red heat till the ash 
is free from carbon. 
Fat.—Many methods for fat determination 
have been devised. The following will suffice for 
all practical work: 
Adams’ Method.—This consists essentially in 
spreading the milk over absorbent paper, drying, 
and extracting the fat in an extraction apparatus; 
the milk is distributed in an extremely thin layer, 
and by a selective action of the paper the larger 
portion of the fat is left on the surface. A 
paper, manufactured especially for this purpose 
by Schleicher & Schuell, is obtainable in strips 
of suitable size. Each of these yields to ether 
only from 0.001 to 0.002 gram of extract. 
Coils made of thick filter-paper, cut into 
strips 6 by 62 cm., are thoroughly extracted 
with ether and alcohol, or the weight of the ex- 
tract corrected by a constant obtained for the 
