On Kreatinius. 



515 



And the effloresced kreatinin (C 4 H : N 3 0) requires 14 times its 

 weight of water for complete solution at 14° C. 



A very pure specimen of the tabular kreatinin x of urine was 

 dissolved to saturation in water kept at 40° C. The saturated solu- 

 tion was then kept at 17° C. for 12 hours. Crystals separated 

 out. 



3*9828 grams of the resulting solution saturated at 17° C. was 

 evaporated to dryness in vacuo over sulphuric acid. The residue 

 weighed 0*3376 gram. Therefore 3*6452 grams of water at 17° C. 

 held in solution 0*3376 gram of the tabular kreatinin, or 1 gram of 

 tabular kreatinin x of urine is soluble in 10*78 grams of water at 

 17° C. 



Allowing for the different temperatures, it appears, therefore, that 

 the solubility in water of the efflorescent kreatinin (C 4 H 7 X 3 0.2H 2 0) 

 before efflorescence is practically identical with that of the tabular 

 kreatinin ol of urine (C 4 H 7 N" 3 0). 



The solubility of kreatinin prepared from the kreatin of flesh is 

 given by Liebig as 1 part in 11*5 parts of water at 16° C. 



Solubility of Tabular Kreatinin x of Urine in AlcoJiol. 



A fine specimen of the tabular kreatinin a was digested with alcohol 

 of specific gravity 0*795 at its boiling point in a continuous extraction 

 apparatus for some hours. The hot alcoholic solution deposited a 

 number of dendritic crystals on cooling. The solution w r as left at the 

 ordinary temperature for 20 hours in a well-corked bottle. 10 c.c. 

 of the solution, whose temperature was 17° C, was then drawn off in 

 a pipette and evaporated to dryness over steam. The residue weighed 

 0*0220 gram. A second 10 c.c. left a residue weighing 0*0216 gram. 

 7*95 grams of absolute alcohol at 17° C. therefore dissolved 0*022 

 gram of the tabular kreatinin. 



Therefore 1 part by weight of the kreatinin dissolves in 362 parts 

 by weight of absolute alcohol at 17° C. 



The solubility of kreatinin prepared from the kreatin of flesh is 

 given by Liebig as 1 part in 102 parts of absolute alcohol at 16° C. 



Determination of the Weight of Cupric Oxide reduced by Efflorescent 

 Kreatinin of Urine and by Tabular Kreatinin x of Urine in Boiling 

 Alkaline Solutions. 



My object in making these determinations being to ascertain how 

 much of the reducing action of normal urine is to be ascribed to the 

 kreatinin which is present in that secretion, I employed the same 

 method therein as in estimating the cupric oxide reduction effected 

 by the urine itself, viz., Pavy's ammoniacal cupric method. 



11*2 c.c. of a solution of the efflorescent kreatinin of urine, containing 



