CHEESE. 75 



butyrate) while oleomargarin gives only the alcoholic 

 odor. 



Butter-Colors. The following coloring matters 

 are stated to have been found in butter : carrot color, 

 annatto, marigold and carthamus flowers, turmeric and 

 certain coal-tar colors. 



The following test, described by E. W. Martin, we 

 have found very satisfactory. Dissolve 2 parts of 

 carbon disulfid in 15 parts of alcohol, by adding small 

 portions of the disulfid to the alcohol and shaking 

 gently ; 25 c. c. of this mixture are placed in a con- 

 venient tube, 5 grams of the butter-fat added, and 

 the tube 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 min- 

 utes. If the amount of the coloring matter is small 

 more of the fat may be used. 



CHEESE. 



Cheese is obtained by the action of rennet, which 

 is usually derived from the fourth stomach of the calf. 

 The action is due to a non-organized ferment (enzyme) 

 rennin, which acts directly on the proteids, and does 

 not produce its effect through the intervention of 

 acid. The curd (cheese) undergoes, by keeping, va- 

 rious decompositions, some essentially putrefactive, 

 and undoubtedly due to the action of microbes. 

 These changes, known as ripening, do not take place 



