METHODS OF TESTING MILK FOR CASEIN 193 



with skim-milk ; in case of fading, the addition of one 

 or more drops of carmine ink is needed. Skim-milk 

 is used to avoid the presence of fat which, in case of 



a 



FIG 51 APPARATUS AND REAGENTS REQUIRED IN THE NEW YORK 

 STATE STATION VOLUMETRIC CASEIN TEST 



whole milk, separates on standing, adheres to the sides 

 of the flask and obscures the color. 



(b) Use of color-standard. In neutralizing a 

 sample of milk, the color-standard is placed beside the 

 sample under examination for constant comparison 

 after each addition of alkali. The flasks should be 

 placed on a white surface and in a good light. In fresh 

 milks, it is usually found that 3 or 4 cc. of alkali is 



