466 JACOB ROSEXBLOOM 



H N C = O 

 C = C C NH 



II )c = q 



H N C NH X 



and the stable lactim form 



N=C O H 



HO C C NH 



|| || ;c OH 



N C - N 



are distinguished by their solubility. The lactimurate is more stable and 

 less soluble. According to Gudzent the watery solutions are : 



18 37< 



Acid uric acid sodium (lactam) 1 :846 1 :469 



Acid uric acid sodium (lactim) 1 :1270 1 :7l< 



Which form exists in urine we do not know. With a neutral reactk 

 the urine water is at any rate sufficient to hold the uric acid in solution as 

 a sodium salt. That we, notwithstanding, so often observe the sedimen- 

 tium is due to the fact that the solubilities of the acid alkali urates are 

 greatly diminished by the presence of great amounts of alkali ions 



(Ka:K). 



Temperature has a great influence on the solubility of acid sodium 

 urate. It may often be observed that a precipitate which disappears after 

 short boiling does not reappear on cooling and that the urine remains clear 

 for hours and even days. There must therefore be a change produced in 

 the urine by heating. Decomposition of uric acid is not in question; 

 decrease of acidity caused by the small loss of CO 2 cannot work so great 

 a change. One can even make the urine more strongly acid after heating 

 without hastening the formation of a precipitate. This phenomenon of 

 change in solubility may be found at times in urines which give a dense 

 uric acid precipitate on acidification. If one adds the same amount of 

 acid to the heated urine the precipitation may fail or come later. It can 

 be shown that by boiling a change in the solubility state of the colloid is 

 produced. Lichtwitz examined 57 such urines for their colloid conditions. 

 The gold count was made before and after boiling and the time noted that 

 the sediment remained in solution. The gold count increased from two 

 to ten times, i.e., the urine colloids were in a state of precipitation in 

 these urines, and became reversible through boiling, as gelatin by wann- 

 ing goes into a finer separation. In 18 urines that on cooling precipitated 



