FATS AND PHOSPHATIDES 231 



in dilute nitric acid and test for phosphate with ammonium 

 molybdate. A positive test should result. 



v. Saponify % of the lecithin by heating in a flask on the 

 water bath with 20 c.c. of alcoholic NaOH for about 15 minutes, 

 replacing the alcohol if necessary. Evaporate to dryness and dis- 

 solve the soap in water. Boil and observe the soap bubbles. 

 Acidify with hydrochloric acid and allow to stand, warming if 

 necessary. The liberated fatty acids precipitate and float at the 

 surface. 



vi. The choline portion of the molecule also may be recognized 

 by appropriate tests. 



