170 MILK AND DAIRY PRODUCTS PART 



The addition of cocoa-nut oil to the extent of: 



10 per cent, raises the Polenske number O'S-1'2 average 10. 

 15 ,, T4-1-8 1-6. 



20 P9-2-2 1-9. 



If, then, the Polenske number is higher in relation to the 

 Reichert-Meissl number than is given in the above table, there 

 is an indication that cocoa-nut fat has been added, for this is 

 the effect that it has. 



The details of the method are exactly the same as those of 

 Leffman and Beam's modification of the Reichert-Meissl 

 method, but in order to obtain comparable figures very great 

 care must be exercised in following Polenske's directions as to 

 size of distillation flask and condenser, temperature of con- 

 denser water, time of distillation, &c. In Fig. 65 is shown the 

 arrangement and size of the distillation apparatus, and it will 

 be noticed that the tube passing through the cork in the neck 

 of the flask has an opening in the side. 



Five g. of clear filtered butter fat are saponified as usual with 

 20 g. of glycerine and 2 c.c. of caustic soda (1:1) in a 300 c.c. 

 Jena glass flask over a naked flame, and the soap dissolved in 

 90 c.c. of water that has previously been boiled. The solution 

 must be quite clear and colourless, or at most have a yellow tinge ; 

 so on this account all the fats that give a brown solution cannot 

 be investigated. The soap solution, having been warmed to about 

 50, is then decomposed w r ith 50 c.c. of dilute sulphuric acid 

 (25 c.c. per litre), a little powdered pumice stone added (not 

 pieces of pumice stone), and the flask immediately connected to 



