ANIMAL OXIDES WITH AZOTE NOT OILY. 



yellow, or reddish, and which Prout has called purpuric acid 

 Liebig and Wohler have distinguished this substance by the 

 name of murexane. 



SECTION VIII.- 



We obtain this substance when we dissolve murexide in caus- 

 tic potash ; boil the liquid till the blue colour disappear, and then 

 pour into it dilute sulphuric acid. To obtain it pure, we have 

 only to dissolve the murexane thus obtained in potash, and pre- 

 cipitate it by an acid. It has then the form of a very light pow- 

 der, very porous, having a silky lustre, and becoming red when 

 exposed to the vapour of ammonia. It is insoluble in water and 

 in dilute acids ; but soluble without sensible alteration in con- 

 centrated sulphuric acid, from which it is precipitated by wa- 

 ter. It dissolves readily in the alkalies and in ammonia, but 

 without neutralizing them. When newly precipitated, it has a 

 great resemblance to uramile ; but it is easily distinguishable 

 both by its reaction and by its composition. 



When burnt with oxide of copper, it gives azotic and carbonic 

 acid gases in the proportion 1 *. 3. 



The mean of four analyses made in Liebig's laboratory gives 

 its compositions 



Carbon, 32-76 or 6 atoms = 4-5 or per cent 33-33 



Hydrogen, 3-73 or 4 atoms = 0-5 ... 3-70 



Azote . 25-48 or 2 atoms = 3-5 ... 25-93 

 Oxygen, 38-03 or 5 atoms = 5-0 ... 37-04 



100-00 13-5 100-00 



Murexane is not the only product of the decomposition of mu- 

 rexide. We find ammonia combined with the acid, which was 

 employed to throw down the murexane. It may be driven off by 

 the addition of a fixed alkali. If, after having decomposed mu- 

 rexide by dilute sulphuric acid, we separate the murexane by the 

 filter, there remains a colourless liquid, which possesses the fol- 

 lowing characters: 



When placed in contact with nitrate of silver, it assumes a 

 black colour, and deposites in a short time metallic silver, just as 

 would happen to a solution containing alloxantin. Ammonia 

 forms in the liquor separated from the silver a dense white pre- 



* Ann. de China, et de Phys. Ixviii. 322. 



