68 ALLOXAN. 



equal weight of uric acid in small portions, stirring or 

 shaking the mixture constantly. Allow to stand and 

 crystallise, filter through a funnel plugged with 

 asbestos, wash the crystals with water at 0. and dry 

 between filtering paper. 



2. Extract organic matters, such as intestinal con- 

 tents or evacuations in disease with water, and subject 

 to dialysis on parchment paper. Evaporate the dialy- 

 sate at a gentle heat and ultimately let dry sponta- 

 neously. If alloxan be present it will be deposited in 

 crystalline rings which assume a red colour when 

 exposed to the air for some time. 



3. Dissolve alloxan in water or alcohol and add 

 nitric acid, the alloxan will be reprecipitated. 



4. Observe its astringent, taste and acid reaction by 

 litmus. Rub a solution of it on a part of the skin, and 

 observe that it produces a peculiar and disagreeable 

 odour and stains the skin pink, crimson, or purple, 

 after some time. 



5. Boil some alloxan with dilute nitric acid in a test- 

 tube fitted with a cork and bent tube, the latter dipping 

 into a little lime or baryta water. Carbonic anhydride 

 will be evolved, causing a milky turbidity in the lime 

 or baryta water. Nitrate of urea remains in the acid 

 solution, which will give a dense white precipitate with 

 solution of mercuric nitrate. 



6. Add to a solution of alloxan some solution of 

 ferrous sulphate, and a drop of potash; observe the 

 formation of a deep blue solution and precipitate. This 

 solution after filtration shows no specific absorptions 

 before the spectroscope. 



