CHEESE IOI 
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, 
