CHAPTER XIX. 



FATS. 



Saponification. 



1. Take a little melted tallow, add 2 volumes of 10 p - c - NaOH, 



boil with constant agitation for five to ten minutes until 

 the quantity of melted fat which comes to the surface 

 when the tube is held at rest is much diminished. 

 Add water, boil again, cool, run through a wet filter. 

 The filtrate contains the soap which has been formed = 

 saponification. 



2. Neutralise 8 cc of the filtrate, warm, saturate with NaCl, the 



soap will fall in flocculi ; slight warmth assists this 

 separation. 



Bmulsification. 



3. Place in one tube (a) some soap solution, and in another 



(b) the same quantity of water. To each add one-third 

 volume of fresh neutral (litmus paper) olive oil and 

 shake them briskly, place them side by side in the rack 

 to stand for 15 minutes : note the difference in the two 

 emulsions. Tube a will present a uniforn and creamy 

 emulsion. 



4. To some cod liver oil add 1 volume carbonate of soda 



solution. Shake briskly, an emulsion results. Soap is 

 formed by the union of the fatty acid in the oil with 

 the alkali. 



