LARD \ND LARD ADULTERATIONS. 



459 



Example. 



Grains. 

 Weight fat taken 4.907 



N 

 No. cc -JQ alkali used 25.50 



N 

 Less 5cc due to Ice - ( \- acid 20.50 



Weight soluble fat acids 1804 



Per ceut. soluble fat acids 3. 63 



The modification introduced into the above method is in making the 

 flask in which the saponification takes place and from which the dis- 

 tillation is made the same. For this purpose a specially-made flask 

 such as is used in the digestion in the Kjeldahl method of determining 

 nitrogen is employed. This flask is made of extra heavy glass, well an- 

 nealed and quite heavy, so as to resist the pressure of the tension of the 

 alcohol at the temperature of the steam-bath. The sample of fat with 

 the saponifying re-agents having been placed in the flask, a stopper of 

 soft cork is inserted and tied down with a string or wire as represented 

 in Fig. 25. The flask is then placed upon a steam-bath and heated for 

 one hour, at the end of which time the fats will be found saponified and 

 any ether which may have been developed decomposed by the excess 

 of alkali present. After cooling the stopper of the flask is removed, 

 the alcohol evaporated, and the decomposing acid added, and the dis- 

 tillation carried on essentially in the manner described. 



Fig. 25. 



This method of procedure avoids the possibility of any loss which 

 might ensue in transferring the saponified fats from the vessel in which 

 the saponification took place into the distilling flask. 



