CHEESE 71 



Chattaway, Pearmain & Moor use the following modifica- 

 tion: 2 grams of the cheese are placed in a small dish and 

 heated on the water-bath with 30 c.c. of concentrated hydro- 

 chloric acid until a dark, purplish- colored solution is produced. 

 The mixture is now poured into the test bottle, portions of 

 solution remaining in the dish rinsed with the hydrochloric acid 

 fusel-oil mixture into the bottle, and, finally, enough strong hot 

 acid added to fill the bottle up to the mark. It is then whirled 

 for about a minute. The difficulty in this method is to get all 

 the fat into the bottle. It is best to weigh the cheese in the 

 bottle. 



Bondzynksi applies the Werner-Schmid method to the de- 

 termination of fat in cheese, as follows: A weighed quantity 

 of the finely-shredded cheese is placed in the tube and decom- 

 posed with 20 c.c. hydrochloric acid of specific gravity i.i, 

 containing about 19 per cent, true acid. On cautiously warm- 

 ing over wire gauze, the melted fat rises to the surface. After 

 cooling, 30 c.c. of ether are added and the tube warmed very 

 gently until the acid and ethereal solution of fat separate sharply. 

 Centrifugal force helps this, but is not essential. After the vol- 

 ume of ether has been read off, 20 c.c. are pipetted off into a 

 weighed Erlenmeyer flask. From this, the quantity of fat in 

 the entire solution may be calculated. 



The fat of cheese may also be estimated by Cochran's 

 method, page 48. 



Lactose. — This may be estimated by boiling the finely di- 

 vided cheese with water, filtering, and determining the reduc- 

 ing power of the filtrate on Fehling's solution. 



Determination 0] Albuminoid Nitrogen (Stutzer's Method). — 

 0.7 to 0.8 gram of the cheese are placed in a beaker, heated to 

 boiling, 2 or 3 c.c. of saturated alum solution added to decom- 

 pose alkaline phosphate, then copper hydroxid mixture (see 

 below) containing about 0.5 gram of the hydroxid, and stirred 

 in thoroughly; when cold, the mass is filtered, washed with 



