LEUCINE. 143 



sulphuric acid, and evaporate in the water-bath. The hydrochloric 

 acid is expelled by evaporation, from the syrupy, blackish brown 

 residue, which is then dissolved in water and boiled with milk of lime; 

 the excess of lime is removed from the filtered fluid by sulphuric 

 acid, whose excess is removed by acetate of lead, and the lead by 

 sulphuretted hydrogen : in this syrup crystals of tyrosine and leucine 

 are formed, which are separated from one another in the manner 

 already described. 



LEUCINE. C 12 H 13 NO 4 . 



Properties. It occurs in the form of glistening, colourless 

 leaves, which craunch between the teeth, and convey to them the 

 sensation of a fatty matter ; it is devoid of taste or odour, is lighter 

 than water, fuses at above 100, sublimes unchanged when care- 

 fully heated to 170, is soluble in 27*7 parts of water at 17'5, and 

 in 625 parts of alcohol of 0'828 specific gravity, and in much smaller 

 quantities of hot water and alcohol, but is insoluble in ether ; it 

 has no reaction on vegetable colours. No reagent, with the excep- 

 tion of nitrate of suboxide of mercury, precipitates it from its 

 aqueous solution. It dissolves more readily in a solution of caustic 

 ammonia than in water. It dissolves unchanged in concentrated 

 sulphuric and hydrochloric acids, and the solution may even be 

 warmed without the occurrence of decomposition ; it dissolves 

 unchanged in cold nitric acid, but, on boiling, is entirely converted 

 into volatile products. 



One hundred parts absorb about 28 parts of hydrochloric acid 

 gas. Chlorine gas destroys it. On heating its aqueous solution with 

 nitric oxide or any other oxidising agent, leucic acid, C 12 H H O 5 .HO, 

 is formed, nitrogen being developed. 



If, on the other hand, it is fused with hydrated potash, there is a 

 simultaneous formation of carbonic acid, hydrogen, and valerianate 

 of ammonia (C 12 H 13 NO 4 + 3KO+3HO = 2KO.CO 2 + H 3 N + 4H 

 + KO.C 10 H 9 O 3 ). It undergoes the same decomposition during the 

 putrefaction which a solution of pure leucine very readily undergoes 

 when a small quantity of muscular fibre or of albumen has been 

 added. 



Composition. Mulder, following Braconnot's investigations 

 regarding leucine, has recently analysed it, and from his analyses has 

 deduced the formula C 12 H 12 NO 4 ; but still later analyses, instituted 



