LEUCINE. 143 



3. Add to a solution of leucic acid a solution of 

 copper acetate ; green flocks of copper leucate will be 

 precipitated, sparingly soluble in 'water, easily soluble 

 in boiling alcohol; 



4. Add to a concentrated solution of leucic acid a 

 solution of lead acetate ; a white flaky precipitate of 

 lead leucate falls. Boil : part of the precipitate dis- 

 solves, the rest melts into a white mass, which 

 becomes hard and brittle on cooling. 



Leucine, C 6 H 13 N0 2 . 1. Boil one part of cowhorn 

 shavings with four parts of concentrated sulphuric 

 acid and twelve parts of water for six hours, re- 

 newing the water as it evaporates. Add an excess 

 of milk of lime, boil for some hours, strain, and 

 press. Mix the nitrate with a very slight excess of 

 sulphuric acid, and evaporate the nitrate. Spherical 

 crystalline tufts of tyrosine will be first deposited. 

 Separate these, and continue the evaporation, when 

 leucine will be deposited, in scales. 



2. Collect these scaly masses of impure leucine, 

 press them between filter paper. Triturate them in a 

 mortar with slightly warm concentrated nitric acid 

 until dissolved ; dilute the solution with water, and add 

 to it solution of mercuric nitrate as long as a precipi- 

 tate falls ; filter, treat filtrate with sulphuretted hy- 

 drogen ; filter, neutralise the filtrate with ammonia, 

 and evaporate till the leucine begins to crystallise out ; 

 allow to cool, when nearly pure leucine will be depo- 

 sited. 



3. To obtain it perfectly pure dissolve in boiling 



