way by first precipitating with ammonium molybdate, then with 

 magnesium mixture and burn to the pyrophosphate and weigh. 



It was found necessary to modify this method when applied to 

 the separation of the organic from the inorganic phosphorus in the 

 egg. As lecithin is the principal form in which the organic phos- 

 phorus occurs it was though best to study this method when applied 

 to a mixture containing the phosphorus in this form. 



Preparation of Lecithin 



The various authors advise the preparation and purification 

 of lecithin by extracting the egg with absolute alcohol or ether or 

 both separately. Evaporate the extractions to dryness and take up 

 with as little ether as possible; filter and treat with about twice its 

 volume of acetone. The acetone precipitates out the lecithin. Oth- 

 ers use a chloroform solution and acetone as the precipitating 

 agent. Neither of these methods work satisfactorily on the dried 

 eggs as obained from the factory. The following method was used 

 with very good results. The egg extracted with chloroform, the 

 chloroform expelled and the residue dried in a water oven until a 

 thick reddish brown mass was obtained. This mass was dissolved 

 in warm ethyl acetate, when cooled down by means of ice the 

 leci thin separates out and may be filtered off by using a funnel 

 jacketed with ice. The lecithin is obtained on the filter. By re- 

 peating this treatment nearly pure lecithin may be obtained. A 

 sample thus obtained was dried and on analysis gave 9.16 per cent. 

 PzOo 1 . The amount of phosphorus anhydride varies from 8.75 to 

 P.45 per cent. P205. The sample was of a waxy appearance and 

 of a reddish brown color. 



The first thing to be studied is whether the lecithin or various 

 compounds of the egg are broken up yielding phosphorus that will 

 be precipitated with ammonium moylbdate solution when treated 

 with the .2 per cent. HC1 extracting reagent. 



The lecithin purified by the ethyl acetate method was digested by 

 shaking at frequent intervals for three hours. To this extract after 

 filtering ammonium nitrate was added and neutral ammonium 

 molybdate, digested one hour at 60 degrees. There was no yellow 

 ammonium phosphomolybdate precipitated. 



Taking the residue remaining after tin- cxtrai tion of the lecithin 

 w"ith ethvl acetate this residue contains chiefly fats and coloring 



1. Imbert and Merle (Bull, de Pharm. Sud. Ext. May, 1902), Am. de 

 Chim. Anel., 1902, 350-351. 



