520 



Mr. G. S. Johnson. 



Comparison between Kreatinin Hydrochloride prepared by Liebig's Pro- 

 cess from Urinary Kreatin and the Kreatinin Hydrochloride obtained 

 from the Spherical Mercury Salt of Urine. 



When the contents of the tube, in which urinary kreatin has been 

 converted into kreatinin hydrochloride by dry HC1 at 100° C, are 

 dissolved in cold water, three times its weight of which is sufficient 

 for complete solution, there are obtained on evaporation in vacuo over 

 sulphuric acid transparent flattened prisms, which rapidly become 

 opaque on exposure to common air by efflorescence. 



1"26 gram of these crystals (air-dried and weighed at once) lost 

 7'06 per cent, after 48 hours' exposure to common air at 15° C. 

 Being finally dried at 100° C.,they were found to have lost altogether 

 10*9 per cent. 



The formula C 4 H 7 NgO.HCl.H 2 requires 1L04 per cent. H 2 0. In 

 this respect, kreatinin hydrochloride obtained by Liebig's process 

 from urinary kreatin, resembles the kreatinin hydrochloride obtained 

 from kreatinin of flesh by the same process. 



Thus 0*323 gram of air-dried transparent square plates of kreatin 

 hydrochloride, prepared by me from beef by Liebig's process, and 

 crystallised by spontaneous evaporation from cold aqueous solution, 

 lost 12'4 per cent, of their weight when dried at 100° C, which, is 

 rather more than is required by the formula C4H7N3O.HCl.H2O. The 

 occurrence of water of crystallisation in the crystals obtained by 

 spontaneous evaporation of cold aqueous solutions of kreatinin hydro- 

 chloride obtained artificially by Liebig's process from kreatin 

 (whether urinary or sarcous in its origin) is an important means of 

 distinguishing these artificial hydrochlorides from the natural hydro- 

 chloride of urinary kreatinin, the crystals of which I have invariably 

 found to be anhydrous, even when the utmost care is taken to avoid 

 heating their solution (vide Part I of this paper). 



Description of the Preparation of Kreatinins from the Kreatinin Hydro- 

 chloride produced from Urinary Kreatin. 



The same process was adopted in liberating the kreatinin from the 

 artificial hydrochloride as in the case of the hydrochloride of the 

 kreatinin of urine itself. The concentrated aqueous solution was 

 well stirred with excess of pure lead hydrate, at the ordinary tempe- 

 rature, till the reaction to litmus became strongly alkaline. The 

 liquid was then filtered and evaporated in vacuo over sulphuric acid. 

 In some cases this treatment produced efflorescent kreatinin, exactly 

 resembling in crystalline form and in composition the efflorescent 

 kreatinin of urine (C 4 H 7 ]Sr30.2H 2 0) ; whilst in other cases anhydrous 

 tabular crystals were formed, which were found to be crystallo- 

 graphically identical with the tabular natural kreatinin of urine. I 



