DETECTION OF ADULTERATION 53 
and the curd separated from the whey. The 
curd will often collect in a mass; but if this does 
not occur, it must be freed from whey by straining 
through muslin. The curd is macerated for 
several hours in a closed flask, with occasional 
shaking, with ether to extract fat. Annatto 
will also be removed by it. The ether and curd 
are separated and treated as follows: 
The ether is evaporated, the residue mixed 
with a little weak solution of sodium hydroxid, 
and passed through a wet filter; and when this 
has drained, the fat is washed off and the paper 
dried. An orange tint shows annatto, which 
may be confirmed by a drop of solution of 
stannous chlorid, which makes a pink spot. 
If the curd is colorless, no foreign coloring- 
matter is in it; if orange or brown, it should be 
shaken with strong hydrochloric acid in a test- 
tube. 
If the mass turns blue gradually, caramel is 
probably present. The whey should be ex- 
amined for caramel (see page 95). 
If the mass turns pink at once, an azo-color 
is indicated. 
Falsification of the ‘‘Cream-line.’’—The use of 
glass bottles for retail delivery of milk enables 
purchasers to make approximate estimations of 
the richness of the sample by the depth of cream 
formed after standing for some time, this being 
