72 MILK PRODUCTS. 



sides. At the end of an hour the flask, after having 

 been cooled to near the room temperature, is opened. 



Removal of the alcohol. The stoppers having been 

 laid loosely in the mouth of the flask, the alcohol is re- 

 moved by dipping -the flask into a steam bath. The 

 steam should cover the whole of the flask except the 

 neck. After the alcohol is nearly removed, frothing 

 may be noticed in the soap, and to avoid any loss from 

 this cause or any creeping ot the soap up the sides of 

 the flask, it should be removed from the bath and 

 shaken to and fro until the frothing disappears. The 

 last traces of alcohol vapor may be removed from the 

 flask by waving it briskly, mouth down, to and fro. 



Dissolving the soap. After the removal of the alco- 

 hol the soap should be dissolved by adding 100 c. c. of 

 recently boiled distilled water, warming on the ste,am 

 bath with occasional shaking, until solution of the soap 

 is complete. 



Setting free the fatty acids. When the soap solution 

 has cooled to about I45F the fatty acids are separat- 

 ed by adding 40 c. c. of the dilute sulphuric acid so- 

 lution mentioned above. 



Melting the fatty acid emulsion. The flask should 

 now be re-stoppered as in the first instance, and the 

 fatty acid emulsion melted by replacing the flask on 

 the steam bath. According to the nature of the fat ex- 

 amined, the time required for the fusion of the fatty 

 acid emulsions may vary from a few minutes to several 

 hours. 



