64 ALBUMEN. 



But on boiling the whole of the albumen is precipi- 

 tated. After nitration and drying weigh the precipi- 

 tate. This is a good method for estimating the quantity 

 of albumen present in any colourless liquid. 



7. Add a watery solution of creasote, or of crystallised 

 carbolic acid, or of tannic acid, to an albuminous 

 solution. The albumen is precipitated. 



8. Add a solution of salt to the albumen solution, 

 and then phosphoric, tartaric, oxalic, or lactic acid. A 

 precipitate of albumen will ensue. 



9. Expose some undiluted albumen in a thin layer 

 on a white porcelain plate to the air. It will dry into 

 a pale yellowish, translucent, fissured mass, which is 

 slowly but entirely soluble in water. 



10. Chemolyse albumen by the following process : 

 Boil the white of several eggs with excess of dilute 

 sulphuric acid for three hours. Then treat the solution 

 with milk of lime until alkaline. Distil the mixture 

 from a tin bottle, and observe in the distillate ammonia, 

 a compound ammonia, and a volatile sulphur compound, 

 which yields sulphur and sulphuretted hydrogen on 

 addition of an acid. Extract with water, and filter the 

 residue in the bottle. Treat the solution with a slight 

 excess of dilute oxalic acid ; remove the excess of the 

 latter and some sulphuric acid by a little lead acetate, 

 and the excess of the latter by sulphuretted hydrogen. 

 Filter warm, and evaporate to slight crystallisation. 

 All tyrosine with little leucine will crystallise out. 

 Further evaporation will yield more leucine. . The 

 liquor contains several other products, which are dis- 

 tinguished by a powerful green fluorescence. Examine 



