BUTTER 93 
sulfuric acid and four parts glacial acetic acid. 
The contents of the tube are then heated almost 
to boiling and thoroughly mixed by violently 
agitating the bottom of the tube. When now 
allowed to stand and separate, the lower layer of 
mixed acids will be strongly colored wine-red if 
the azo-color be present. Pure butter-fat im- 
parts no color to the acids, or, at most, only a faint 
brownish tinge. 
Turmeric and Annatto.—Martin’s test will 
usually be satisfactory: 2 c.c. carbon disulfid 
are mixed with 15 c.c. of alcohol, by adding small 
portions of the disulfid to the acohol and shaking 
gently; 5 grams of the butter-fat are added to 
this mixture in a test-tube and shaken. The 
disulfid falls to the bottom of the tube, carrying 
with it the fatty matter, while any artificial 
coloring-matter remains in the alcohol. The 
separation takes place in from one to three 
minutes. If the amount of the coloring-matter 
is small, more of the fat may be used. If the 
alcoholic solution be evaporated to dryness and 
the residue treated with concentrated sulfuric 
acid, anratto will be indicated by the production 
of a greenish-blue color. With many samples 
of oleomargarin, a pink tint will be produced, 
which indicates an azo-color. 
Palm od has been used as a coloring agent in 
butter-sutstitutes. Crampton & Simons have 
