232 URIC ACID. 



holic ammonia. Colorless needles, pretty easily soluble 

 in water; fusing point, 106. 



Diethyl-sulphocarbamide, CS(KELC 2 H 5 ) 2 . Is pre- 

 pared in the same way from ethyl mustard-oil and 

 ethylamine ; or by boiling ethylamine ethylsulphocar- 

 bamate (p. 227) on a water bath. Crystals, that fuse 

 at 77, which, under the influence of phosphoric anhy- 

 dride or hydrochloric acid gas, yield ethyl mustard-oil. 



Uric Acid. 

 C 5 H 4 N 4 3 . 



Occurrence. In urine, urinary calculi, and urinary 

 sediments (compare Animal Chemistry). In small quan- 

 tity in the blood and in the muscular fluid. In the 

 form of sodium urate in the concretions found in the 

 joints of gouty patients. In the excrements of birds, 

 amphibious animals, insects, these excrements often 

 consisting entirely of sodium urate. 



Preparation. Calculi, consisting of uric acid, or, 

 better, the excrement of serpents (ammonium urate, 

 with various foreign substances), are dissolved in dilute 

 caustic potassa or soda at the boiling temperature, the 

 solution filtered and poured boiling hot into an excess 

 of dilute hot sulphuric acid. The precipitated uric 

 acid is washed out and dried. If it is not white, it is 

 redissolved and again precipitated. Or a current of 

 carbonic anhydride is conducted into the solution of 

 uric acid in potassa, by means of wJiich, white acid 

 potassium urate is precipitated; or the solution is 

 mixed with a solution of ammonium chloride, when 

 acid ammonium urate is precipitated. In both cases 

 the precipitated salts are washed out, and decomposed 

 by adding them to boiling dilute hydrochloric acid. 



In order to prepare uric acid from guano, the latter 

 is boiled with a solution of borax (1 part borax in 120 

 parts water), filtered, and the uric acid precipitated 

 with hydrochloric acid. Or, dried and finely pulverized 

 guano is added to an equal weight of concentrated 



