CREATININE. 249 



direct combination of methylglycocol (sarcosine, p. 85) 

 with cyanamide. 



Colorless, lustrous prisms, of a slightly hitter taste, 

 very difficultly soluble in cold water, more easily in 

 hot, insoluble in absolute alcohol. 



It combines with acids, forming crystallizable salts. 

 By heating with baryta water, it yields urea, sarco- 

 sine and methylhydantoine (p. 245). By boiling with 

 mercury oxide, oxalic acid, carbonic anhydride, and 

 methyluramine are formed. 



Creatinine, C 4 H 7 J^ 3 0, does not occur in muscular 

 flesh ; is, however, contained in urine in considerable 

 quantity (in normal urine of twenty-four hours, 1-1.3 

 grms. creatinine). It is a decomposition-product of 

 creatine. Even by evaporating its aqueous solution 

 with the aid of heat, creatine is partially converted 

 into creatinine ; if acetic acid is previously added the 

 conversion is complete. 



In order to prepare it from urine, this is quickly 

 evaporated to from one-eighth to one-tenth its volume, 

 precipitated by calcium chloride and milk of lime, 

 and the filtrate evaporated until the sodium chloride 

 crystallizes out. From the mother liquid the creati- 

 nine is precipitated by means of a thick solution of zinc 

 chloride, free of hydrochloric acid. In a few days, a 

 thick, crystalline pulp is deposited which is washed 

 with cold water, then dissolved in boiling water, 

 and decomposed by boiling with lead hydroxide. On 

 evaporating this solution creatinine remains behind, 

 still impure from the presence of some creatine, from 

 which it can be separated by dissolving in absolute 

 alcohol. 



Colorless prisms, much more soluble in alcohol and 

 water than creatine. Strong base, reacts alkaline and 

 drives out ammonia from its salts. Unites also with 

 acids and a few salts. Creatinine-zincochloride, 

 2(C 4 H 7 N 3 0) + ZnCl 2 , is particularly characteristic. It 

 is a granular, crystalline powder, difficultly soluble in 

 water, insoluble in alcohol. It dissolves in hydro- 

 chloric acid, forming creatinine-zincochloride hydrochlo- 



