< ANIMAL ACIDS CONTAINING AZOTE. 



solution reddens litmus-paper. Dr Pearson states it to be inso- 

 luble in cold water, and with his statement my trials agree. It 

 certainly requires more than 10,000 times its weight of cold 

 water to dissolve it. Muriatic acid does not dissolve it, nor sul- 

 phuric acid, but it dissolves with effervescence in nitric acid 

 when assisted by heat, and if the solution be cautiously evapo- 

 rated to dryness, the residue gradually assumes a beautiful pink 

 colour. Water dissolves this residue, and assumes the same pink 

 colour, but it gradually fades and disappears. The alkaline car- 

 bonates do not dissolve uric acid, but it dissolves readily in caus- 

 tic potash or soda ley, and also in ammonia, though less readily. 

 The alkaline solutions are promoted by heat. It decomposes soap 

 when assisted by heat, as it does also the alkaline sulphurets. 

 Lime-water also dissolves uric acid, as was first shown by Scheele. 

 It is insoluble in alcohol and ether. 



M. Lipowitz* has made some experiments on the solubility of 

 uric acid, which deserve to be stated. One part of carbonate or 

 bicarbonate of potash or soda, dissolved in 90 parts water, 

 dissolves two of uric acid. The mixture must be boiled. During 

 the boiling, the carbonic acid is expelled and an alkaline urate 

 formed. On cooling, the urate is ^deposited in warty crystals, 

 which require much water to dissolve them. The affinity of uric 

 acid for bases is augmented by heat. When uric acid is boiled 

 with a solution of acetate of potash, the acetic acid is disengaged 

 and urate of soda formed. On cooling, the acetic acid again 

 displaces the uric. When one part of borax is dissolved in nine- 

 ty parts water, the solution dissolves little more than one part 

 of uric acid, but the solution does not require heat. A gelati- 

 nous biurate of soda separates. When this salt is burnt, it leaves 

 carbonate of soda. When we add boracic acid so as to form 

 2 atoms biborate of soda -f 1 atom uric acid, and heat, we get 

 2 atoms urate of soda -f- 1 atom quaterborate of uric acid. 

 On cooling, we have 1 atom biurate of soda -f- 1 atom biborate 

 of soda -f 1 atom biborate of uric acid. 



When phosphate of soda is dissolved in water and the solution 

 boiled with uric acid, urate of soda is formed, which is deposited 

 on cooling, and the liquid becomes acid. 



Carbonate of lithia requires 200 times its weight of water to 

 dissolve it. If it be suspended in water, mixed with uric acid, 



* Ann. der Pharm. xxxviii. 348. 



