144 



KREATIN. 



kreatin which may be found in urine is due to the conversion of 

 kreatinin into kreatin during its extraction, since it has been 

 shewn l that the more rapidly the separation is effected, the less 



FIG. 9. KREATIN CRYSTALS. ( Krukenberg after Kiihne.) 



is the quantity of kreatin obtained, and the greater, the amount 

 of kreatinin. 



In the anhydrous form kreatin is white and opaque, but crys- 

 tallises with one molecule of water in colourless transparent 

 rhombic prisms. 



The crystals are soluble in 75 parts of cold water, extremely 

 soluble in hot ; slightly soluble in absolute alcohol, they are more 

 soluble in dilute spirit and are insoluble in ether. The aqueous 

 solutions are neutral in reaction. 



Kreatin is a very weak base, scarcely neutralising the weakest 

 acids, with which it forms soluble crystalline compounds. 



Preparation. Most conveniently from ' Liebig's Extract.' This 

 is dissolved in 20 parts of water and precipitated by a slight ex- 

 cess of basic acetate of lead. The filtrate is then freed from the 

 lead salt by means of sulphuretted hydrogen and concentrated at 

 moderate temperature (avoid boiling) to a thin syrup. On stand- 

 ing in a cool place for two or three days the kreatin crystallises 

 out. The crystals are removed by filtration, washed with 88 p. c. 

 alcohol, and purified by recrystallisation from water. 2 



Kreatin yields no very striking reactions by means of which it 

 can readily be identified. It reduces Fehling's fluid by prolonged 

 boiling without any separation of cuprous oxide. On boiling in 

 presence of alkaline mercuric oxide, a transient red colour is ob- 

 tained and finally a separation of metallic mercury. The reac- 



1 Dessaignes, Jn. de Pharm. et Chim. (3) T. xxxii. (1857), p. 41. 



2 The mother-liquor from the kreatin may be used for the preparation of 

 hypoxanthin and sarcolactic acid. Drechsel, Darstell. physiol.-chem. Prdparate, 

 1889, S. 29. 



