CHEESE lOI 



surface, at a point one-third of the distance from 

 the edge to the center of the cheese. The plug 

 should reach entirely through, or only half-way 

 through, the cheese. When possible, draw three 

 plugs — one from the center, one from a point 

 near the outer edge, and one from a point half- 

 way between the other two. For inspection 

 purposes, the rind may be rejected; but for 

 investigations requiring the absolute amount of 

 fat in the cheese, the rind is included in the 

 sample. It is preferable to grind the plugs in a 

 sausage machine, but when this is not done, 

 they should be cut very fine and carefully 

 mixed. 



Water. — Between 2 and 5 grams of the sample 

 should be placed in a weighed platinum or 

 porcelain dish which contains a small amount of 

 material, such as freshly ignited asbestos or sand, 

 to absorb the fat that may run out. This is then 

 heated in a water-oven for ten hours and weighed ; 

 the loss in weight is considered as water. If 

 preferred, the dish may be placed in a desiccator 

 over concentrated sulfuric acid and dried to con- 

 stant weight, but this may require many days. 

 The acid should be renewed when the cheese 

 has become nearly dry. 



Fat. — The extraction- tube described on page 16 

 is prepared as follows: The perforations in the 

 bottom of the tube are covered with asbestos, 



