BUTTER 95 



a few seconds. If palm oil be present, the heavier 

 layer separating will be blue with a tint of green. 



Egg-yolk has been proposed as a color for 

 oleomargarin, and although its use is unlikely, 

 the possibility of it should be borne in mind. 

 To detect it, about lo grams of the filtered fat 

 should be shaken with warm alcohol, the liquid 

 drawn off as closely as possible and evaporated 

 to dryness. The coloring matter of egg-yolk 

 is soluble in alcohol, but insoluble in water. It 

 may be distinguished from turmeric by moisten- 

 ing it with a few drops of a mixture of boric and 

 hydrochloric acids, and drying at a gentle heat. 

 Turmeric becomes brown ; egg-color is not affected. 

 Egg-yolk contains considerable lecithin, a phos- 

 phoric acid derivative. Pure fats contain no 

 phosphorus compound. If, therefore, a few 

 grams of the fat, carefully freed from water or 

 curd, are charred and the mass extracted by 

 boiling with nitric acid, the filtered solution 

 should not give an appreciable precipitate with 

 ammonium molybdate. 



Vegetable colors may be detected by boiling 

 up the filtered fat with water, drawing off the 

 watery liquid, adding a few drops of hydrochloric 

 acid and heating the mixture with a piece of clean, 

 undyed wool. True butter colors will not dye 

 wool under these circumstances. 



Caramel may be detected by shaking the 



