VITELLIN. 365 



form of phosphate of lime; moreover his amount of sulphur is 

 obviously too small, since he only determines this substance in the 

 moist way. 



To give a general idea of the composition* of this body, we 

 append the mean numbers obtained by Gobley and by v. 

 Baumhauer. 



Gobley v. Baumhauer. 



Carbon 52-264 .... 52'72 



Hydrogen 7*249 .... 7'09 



Nitrogen 15-061 .... 15'47 



Sulphur 1-170 .... 0-42 



Phosphorus .... .... 1-020 .... 



Oxygen 23'236 .... 24'30 



100-000 100-00 



Berzelius conjectures that we are here not dealing with a 

 simple substance, but with an admixture of substances, as is unfor- 

 tunately the case with most of the protein-compounds. Vitellin, 

 extracted with indifferent menstrua, contains 4 '043$- of phosphate 

 of lime. 



Preparation. Soluble vitellin, in a pure state, that is to say, 

 free from yolk-fat and from yolk-globules, has not yet been exhi- 

 bited. Gobley has only attempted to ascertain its reactions after 

 stirring the yolk of egg with water and allowing the emulsive con- 

 stituents, as much as possible, to deposit themselves. In its coa- 

 gulated form we can obtain it in a far purer state ; boiled and 

 triturated yolk of egg is extracted with ether, alcohol, and water, 

 then dissolved in acetic acid, and precipitated therefrom by 

 ammonia, with, however, such precaution that the fluid remains 

 sufficiently acid to retain the phosphate of lime in solution ; the 

 gelatinous precipitate is then dried and extracted with water and 

 alcohol. 



Tests. The methods of recognising and quantitatively determin- 

 ing vitellin are sufficiently obvious from our description of the pro- 

 perties of this body. 



Physiological Relations. 



Occurrence. Hitherto vitellin has only been recognised in the 

 yolk of egg, of which, according to Berzeliusf, it constitutes about 

 17^-, or, according to the most recent investigations of Gobley, 



* [Vitellin has also been recently analysed by Noad. See the Chemical 

 Gazette, vol. 5, p. 409. G. E. u.] 

 t Jahrb. d. Ch, Bd. 9, S. 650. 



