On Kreatinins. 



525 



colour than that of the efflorescent kreatinin of urine, but it has the 

 same composition, as shown from the following analysis : — 



Gold Salt of Efflorescent Kreatinin from Kreatin. — 0*520 gram gave 

 0*226 gram Au, equivalent to 43*461 per cent. 



Kequired for 

 Found. C 4 H 7 N 3 O.HCl.AuCl 3 . 

 Au 43*461 43*43 



The gold salts of natural kreatinins from urine may be readily 

 distinguished from those of artificial kreatinins obtained from the 

 urinary kreatin, by the action of ether, which decomposes the latter, 

 but has no action upon the former. When applied to the crystals of 

 artificial kreatinin auric chloride, ether renders them opaque, dis- 

 solving out auric chloride and leaving the hydrochloride of the 

 kreatinin. 



The crystals of gold salt of the natural kreatinin on the contrary 

 remain unchanged under ether. 



Also, if ether be added to the alcoholic solution of the natural 

 kreatinin in auric chloride, no change takes place, but it causes a 

 precipitate of the kreatinin hydrochloride when added to the alcoholic 

 solutions of the gold salts of the artificial kreatinins. 



Solubility in Water and Alcohol of Tabular Kreatinin oc. from Urinary 



Kreatin. 



Parts by weight of water at 

 Weight of solution in Weight of residue 16*5 C. required to 



water, saturated at 17° C. dried at 100° C. dissolve 1 part of base. 

 5*0412 grams 0*4314 gram 10*68 parts 



This agrees very closely with the solubility of natural tabular 

 kreatinin in water, which requires 10*78 parts at 17° C. 



The solubility of the artificial tabular kreatinin in alcohol is, 

 however, greater than that of the natural base. At 18*5° C, 324 parts 

 of absolute alcohol dissolve 1 part by weight of tabular kreatinin a. 

 from urinary kreatin, whereas the natural tabular kreatinin of urine 

 requires 362 times its weight at 17° C. 



Effects of Re-crystallisation from Aqueous Solution at Different Tempe- 

 ratures of Kreatinins obtained from Urinary Kreatin. 

 There appear to be four varieties of kreatinin obtainable from 

 urinary kreatin. 



(1.) Efflorescent kreatinin a, which, having effloresced, recrystal- 

 lises in the same form after spontaneous evaporation of its cold 

 aqueous solution. . 



