CREATININE. 141 



in short transparent prisms ; from water, in broad leaves ; with 



bichloride of platinum it yields an easily soluble compound which 



+ 



crystallises in crimson prisms = K.HCl + PtCl 2 . 



+ 



Sulphate of creatinine, K.HO.SO 3 , forms concentrically grouped, 

 transparent, square tablets, which lose no water at 100, and remain 

 perfectly translucent. 



With the above-named metallic salts creatinine yields crystal- 

 lisable compounds, all of which are basic double salts ; with the 

 salts of the oxide of copper it forms crystallisable double salts of a 

 beautiful blue colour. 



Preparation. The most simple method of obtaining creatinine 

 is from creatine, by exposing a mixture of the latter and of hydro- 

 chloric acid to evaporation, till all excess of acid is volatilised. 

 The base is best separated from the hydrochlorate, which is thus 

 formed, by digestion with hydrated oxide of lead. The mode 

 of preparing creatinine from urine has been already indicated in our 

 remarks on creatine ; moreover, when it is to be prepared from the 

 juice of flesh, the chloride of zinc compound must be employed and 

 decomposed by hydrated oxide of lead ; the creatinine may then 

 be readily separated from the creatine by alcohol. 



Tests. This body may generally be distinguished with facility 

 from other animal substances, when it is separated as much as 

 possible from adherent organic substances. Its alkaline reaction, 

 its property of forming crystalline compounds with the above- 

 named metallic salts, the easy solubility of the compounds which 

 it forms with bichloride of platinum and similar salts, are more 

 than sufficient to characterise it. 



Physiological Relations. 



Occurrence. It is only in the muscles and in the urine that 

 Liebig has found creatinine. Regarding the quantity in which it 

 exists, nothing is yet known, except that from Liebig^s investiga- 

 tions it appears that in the muscles there is far more creatine than 

 creatinine, while in the urine the amount of creatinine very much 

 exceeds that of creatine. 



According to Scherer* it is highly probable that the Liquor 

 Amnii contains creatinine. 



Origin. From the facts which have already been communicated 

 it can hardly be doubted that creatinine is produced from creatine ; 

 for even if Liebig had not afforded the most decisive proof, by the 



* Zeitschr. f. wissenschaftl. Zoologie. Bd. 1, S. 91. 



