154 PHYSIOLOGICAL AND PATHOLOGICAL CHEMISTRY. 



and then digested twenty-four to forty-eight hours with one 

 liter of artificial gastric juice (see chapter on Digestion, 

 page 40). The albumin passes into solution as acid albu- 

 min, albumose, and peptone, and an insoluble residue of 

 paranuclein or a mixture of paranuclein and paranucleic 

 acid l remains. Filter this off, wash with water, alcohol, and 

 ether, and show the presence of phosphorus by fusing with 

 soda and saltpeter (see chapter on Milk, page 9) , 



II. Preparation of Vitellin, Detection of Lecithin Direct. 



Shake vigorously the yolks of two fresh eggs in a wide- 

 necked glass-stoppered vessel with 200 cc. of pure ether 

 which is free from acid, and then add 5 cc. of alcohol. The 

 addition of the alcohol causes a viscous, slimy precipitate 2 

 to settle from the turbid mixture. Pour off the ether solu- 

 tion as completely as possible and add 100 cc. of a 15 per cent, 

 sodium chloride solution to the precipitate. On shaking the 

 precipitate dissolves in the salt solution, forming a somewhat 

 turbid fluid; place the fluid in a separating-funnel and shake 

 it with an equal volume of ether. It will then become almost 

 clear. Separate the aqueous fluid and let it stand till next 

 day; usually the fluid becomes turbid again. Remove this 

 turbidity by shaking again with ether. Draw off the aqueous 

 fluid again, measure it and pour it into ten times its volume 

 of water. Filter off the precipitate, which forms, next day, 

 and wash with water and then with alcohol. In this con- 

 dition the precipitate will contain a considerable quantity of 



1 This residue sometimes contains a very large amount of phosphorus, 

 as much as 9 per cent. 



2 Frequently a precipitate forms even on shaking with ether alone ; 

 this precipitate is always flocculent and is insoluble in sodium chloride 

 solution. When this phenomenon is observed further work with the 

 material is useless. Presumably the age of the eggs has some influence 

 on their conduct. 



