124 MR. EDWARD 8CHUNCK ON SOME 



ing alcohol, I dried it, added a quantity of hydrate of soda, 

 equal in weight to that of the dry residue, together with a 

 little water, and then heated the mixture over the fire in 

 an iron ladle, with the precautions which are usually ob- 

 served in the preparation of leucine and tyrosine from animal 

 matters. The decomposition was accompanied by a copious 

 evolution of gas, and a strong smell of ammonia, the latter 

 being probably derived for the most part from the colour- 

 ing-matter present, which had not been completely re- 

 moved by the alcohol. The disengagement of gas having 

 ceased, the mass was treated with boiling water, in which 

 it dissolved almost entirely, yielding a dark-brown solution. 

 To this there was added an excess of acetic acid, which 

 gave a brown flocculent precipitate. This having been 

 filtered off, the liquid was evaporated. During evaporation 

 it deposited a considerable quantity of a brownish- white 

 crystalline powder, consisting of oxalate of soda. This 

 was filtered off, purified by recrystallization from boiling 

 water, and converted into oxalate of lead, from which there 

 was obtained, in the usual manner, a quantity of pure 

 crystallized oxalic acid, weighing 18*3 grms. The mother- 

 liquor of the oxalate of soda was evaporated. It left a 

 dark-brown syrup, which was dissolved in boiling alcohol, 

 and mixed with concentrated sulphuric acid as long as any 

 sulphate of soda was precipitated. The latter having been 

 filtered off, acetate of lead was added, and the liquid, after 

 being filtered from the precipitated sulphate of lead, was 

 deprived of its excess of lead by means of sulphuretted 

 hydrogen, filtered again, and evaporated. The brown 

 syrup which remained was mixed with a large quantity of 

 alcohol and left to stand for several weeks. During this 

 period the liquid gradually deposited a quantity of white 

 crystalline needles, which, after being filtered off, washed, 

 and dried, weighed 0*6 grm. These crystals possessed the 

 properties of tyrosine, and were quite free from leucine. 



