UKEA. 173 



for four hours, renewing the water as it evaporates. 

 Dilute with water, add an excess of milk of lime, and 

 strain, exhausting the residue with boiling water. 

 Evaporate the filtrate and extracts to about two thirds 

 of the bulk of the dilute sulphuric acid. Neutralise 

 with sulphuric acid, and allow the whole to stand. 

 Impure tyrosine crystallises out. 



2. Purify and decolorise by dissolving the tyrosine 

 in a little hydrochloric acid and boiling the solution 

 with animal charcoal. Filter and precipitate the 

 tyrosine by adding acetate of soda solution. Crystal- 

 lise the tyrosine by dissolving in a little hot strong 

 ammonia, and allowing to cool, when the tyrosine will 

 separate out in white acicular tufts. 



3. Tyrosine is moderately soluble in boiling water, 

 very sparingly soluble in cold water, almost insoluble 

 in alcohol, it is easily soluble in hydrochloric acid, 

 ammonia, &c. 



4. To a small portion of tyrosine add a little Nord- 

 hausen sulphuric acid ; the tyrosine dissolves, let stand 

 for some time; dilute rapidly with water, neutralise 

 the solution with baryum carbonate, filter, add to the 

 filtrate some neutral solution of ferric chloride when a 

 violet colour is produced. 



5. Heat some tyrosine in a glass tube, it decom- 

 poses, evolving a strong agreeable smell. 



6. Add to an aqueous solution of tyrosine a little 

 mercuric nitrate with mercurous nitrate, a pink colour 

 and red precipitate will be produced on warming. 



Urea, CH 4 N 2 0. 1. Evaporate urine to dryness on 



