318 MANUAL OF MILK PRODUCTS 



give about the right temperature. The temperature may be 

 adjusted by bringing the flame up against the cup or by lower- 

 ing it as the case demands. The double-walled cup containing 

 the tallow between the walls should be heating while the operator 

 is preparing the cheese sample. When the temperature reaches 

 145 C., the flask containing the cheese is put in place. If the 

 temperature rises a few degrees higher during the test, it will 

 do no harm if it is soon lowered to the proper point. 



The drying flask is so shaped that particles of cheese will 

 not spatter out during the drying process. The thermometer 

 should register temperature changes up to 200 C. ; then, if 

 it should become overheated by accident, it would not break 

 so soon. The small tripod and alcohol lamp and thermometer 

 can be secured from any concern supplying chemical apparatus. 

 Any scales like a butter-moisture scales that will weigh accu- 

 rately to one-tenth of a gram will serve for weighing out the 

 5-gram sample. 



The same apparatus may be used for determining the mois- 

 ture in butter, the only difference between the two operations 

 being that in testing butter for moisture, 10 grams of butter 

 are taken in place of 5 grams as in testing cheese. 



TEST FOR CASEIN IN MILK (Adapted from Hart [Wis. Bui. 156]) 



This method makes use of a specially designed test bottle 

 by which the percentage of casein can be read directly (see 

 Fig. 58). 



Each division of the scale represents .1 c.c. and .2 per cent of 

 casein where 5 c.c. equivalent to 5.15 grams of milk are used 

 in the test, assuming the specific gravity of normal cow's milk 

 as 1.030. The graduations extend from zero to 10 per cent. 

 This is amply sufficient for all normal milks. The 10 per cent 

 mark represented on the scale should correspond to exactly 

 5 c.c. 



