514 



Mr. G. S. Johnson. 



Supported by the analyses of mercury and platinum salts, and of 

 the hydrochloride, these analyses leave no doubt that the empirical 

 formula of the reducing base of urine is C 4 H 7 N 3 0. 



Gold Salt of the Kreatinin of Urine. 



Both the tabular kreatinin «. of urine and the efflorescent kreatinin 

 of urine, when dissolved in dilute hydrochloric acid and mixed with 

 a concentrated aqueous solution of auric chloride, yield large thin 

 plates of kreatinin- auric chloride. This salt is remarkably stable. 

 The crystals are permanent in the air, possess a brilliant golden- 

 yellow lustre, and undergo no change at 100° C, except a temporary 

 darkening of colour, which disappears again on cooling. 



The analysis of this salt confirms the view that the molecular 

 weight of the reducing kreatinin of urine is 113. 



Analysis of Gold Salt of the Efflorescent Kreatinin of Urine. 



Weight of 

 kreatin in-auric 

 chloride taken 

 in grams. 



Weight of 

 gold found. 



Weight of 

 chlorine 

 found. 



Weight of 

 gold in 100 

 parts. 



Weight of CI 

 in 100 parts. 



0-2670 



0-1165 



-08324 



43-63 



31-17 



These results agree with the formula C 4 H 7 N" 3 O.HCl.AuCl. 



Found. Theory. 



Au 43-63 43-43 



CI 31-17 31-37 



Determination of the Solubility in Water of the Efflorescent Kreatinin and 

 of Tabular Kreatinin a, of Urine. 



Some solution of efflorescent kreatinin of urine, which was deposit- 

 ing crystals over sulphuric acid at 14° C, was poured off from these 

 crystals into a tared dish, weighed, and evaporated to dryness in vacuo 

 over sulphuric acid. 



The residue was further dried at 100° C. and then weighed. 



4934 grams of the aqueous solution saturated at 14° C. left a 

 residue (effloresced K.) which dried at 100° C. weighed 0329 gram. 



Therefore 4-605 grams of water at 14° C. held in solution 0'329 

 gram of effloresced kreatinin, corresponding with 0'4338 gram of 

 efflorescent kreatinin (0 4 H 7 N 3 0.2H 2 0). 



Hence the efflorescent kreatinin (C 4 H 7 ]Sr30.2H 2 0) requires 10*6 times 

 its weight of water at 14° C. for complete solution. 



