74 ANIMAL ACIDS CONTAINING AZOTE, 



are formed. These three may be separated from each other in 

 the following way. Saturate the acid liquid with carbonate of 

 lime, and filter in order to get rid of the sulphate of lime formed, 

 and then evaporate to dryness^ A yellowish mass remains, hav- 

 ing the flavour of boiled meat. If we boil this matter with alco- 

 hol of O845, two of the three principles are dissolved. The alco- 

 holic solutions are mixed and distilled. The residue taken out of 

 the retort is evaporated to dryness, and what remains is treated with 

 a small quantity of alcohol of 0-83. An extractive looking sub- 

 stance is dissolved, which attracts moisture from the air, and has 

 the smell and taste of roasted meat. 



The portion insoluble in alcohol of 0-83 has been called by 

 Braconnot leucin (from Xsuxos, white.) It is a white powder solu- 

 ble in water and crystallizable. It generally contains some fo- 

 reign matter, from which it may be freed by cautiously adding 

 solution of tannin. If, after filtering, we evaporate till a pelli- 

 cle begins to appear on the surface, and then leave it at rest, a 

 great number of small round grains are deposited, flat, and hav- 

 ing an elevated margin so as to resemble some buttons. These 

 crystals are leucin. 



Leucin crackles under the teeth ; its taste resembles that of 

 boiled meat When heated to 212 it melts and undergoes a 

 partial decomposition, giving out at the same time the smell of 

 roast meat. One portion sublimes unaltered in the form of small 

 white opaque crystalline grains, while at the same time there 

 comes over into the receiver ammoniacal water and a little em- 

 pyreumatic oil. Leucin is very soluble in water and but little 

 soluble in alcohol. But hot alcohol dissolves a greater portion 

 than it can retain when cold. The aqueous solution of leucin is 

 not precipitated by diacetate of lead nor by any metalline salt, ex- 

 cept pernitrate of mercury, which throws it down completely in the 

 state of a white magma, while the supernatant liquor becomes red. 



To obtain nitro-leucic acid the leucin is to be dissolved in ni- 

 tric acid by means of a gentle heat. A slight effervescence takes 

 place, but no red vapours appear. When sufficiently concen- 

 trated the liquid concretes into a mass of white crystals. When 

 freed from nitric acid by pressure between the folds of blotting- 

 paper and purified by a second crystallization, these crystals con- 

 stitute nitroleucic acid. 



Its taste is sour but weak. It combines with bases and forms 

 salts called nitroleucates. Only two of them, nitroleucate of lime 



