146 BASIC BODIES. 



casein (Iljenko* and Bopp,f) and of gluten (Walter Crum.J) I 

 casein, or any other albuminous body, be fused with equal part; 

 of hydrated potash, and the tyrosine extracted from the dissolvec 

 mass in the manner already described, the leucine crystallises fron 

 the mother- liquid, and is readily purified by recrystallisation frorr 

 alcohol. If gelatin be treated in a similar manner, or boiled for i 

 long time in potash ley, we obtain leucine and glycine after saturating 

 with sulphuric acid and removing the sulphate of potash by alcohol 

 and as glycine is far the less soluble of the two in alcohol, the sub- 

 stances may be thus easily separated from one another. Leucine is 

 however, also formed by the action of concentrated sulphuric 01 

 hydrochloric acid on albuminous substances; if, for instance, flesh 

 be gently warmed with an equal volume of concentrated sulphuric 

 acid, then boiled for nine hours with double its weight of water, 

 the acid saturated with lime, and the residue of the filtered solution 

 extracted with alcohol, we obtain on evaporation impure crystals 

 of leucine, which must be purified by recrystallisation. On fusing 

 equal parts of a protein-compound and hydrated potash, but inter- 

 rupting the operation before the mass has become yellow, (as was 

 necessary for the preparation of tyrosine,) we obtain only leucine 

 according to the method given for tyrosine, since the latter seems 

 to be formed from the former by prolonged action. 



Tests. If the leucine be obtained in a state of tolerable purity, 

 and the properties coincide with those known to pertain to leucine, 

 its decomposition into valerianic acid, &c., and its behaviour with 

 nitric acid afford tolerably certain means of distinguishing it. An 

 elementary analysis might, however, be not altogether superfluous, 

 since it may be expected that there are a number of similar bodies 

 for whose discovery and detailed description we may daily look. 



SARCOSINE. C 6 H 7 NO 4 . 



Properties. Broad, colourless, transparent plates or right 

 rhombic prisms, acuminated on the ends by surfaces set perpendi- 

 cular on the obtuse angles, melting at 100, and subliming unchanged 

 at a somewhat higher temperature. Sarcosine is extremely soluble 

 in water, sparingly soluble in alcohol, and insoluble in ether; the 



* Ann. d. Ch. n. Phann. Bd. 58. S. 264-273. 



t Ibid. Bd. 69, S. 19-37. 



$ Berzelius, Lehrb. d. Ch. Bd. 9, S. 684. 



