74 REPORT—1840. 
having found that urea, unlike most organic substances, resists the 
oxidizing agency of permanganate of potash, thought that if urea could 
be obtained from uric acid by the action of that salt, the argument for 
its pre-existence would be much strengthened ; as, if only the elements 
of urea were present, the oxidizing agency of the permanganate would 
most likely prevent its formation. On trying the experiment a large 
quantity of urea was obtained, along with oxalic acid, and a new acid, 
probably formed by the oxidation of allantoine. The author further 
described the acetate of urea, a salt which was formed in his experi- 
ments. 
On a New Process, communicated by Prof. Liebig, for preparing 
Murexide. By Professor GRrcory. 
The process described in this communication for preparing the very 
singular and beautiful compound, termed murexide by Liebig and 
Wohler, and purpurate of ammonia by Prout, is quite certain, and very 
productive. It consists in adding a boiling solution of seven grains of 
alloxan and four grains of alloxantine in 240 grains of water, to 80 
grains of a cold and strong solution of carbonate of ammonia. The 
mixture instantly acquires a deep purple colour, and on cooling de- 
posits the golden-green crystals of murexide. 
On the Preparation of Alloxan, Alloxantine, Thionurate of Ammonia, 
Uramile, and Murexide. By Professor GreGory. 
To prepare alloxan from uric acid, Liebig and Wohler used nitric 
acid, sp. gr. 1°42, and separated the acid liquid from the crystals by 
means of a porous brick, thus losing the whole mother liquid. The 
author uses nitric acid of sp. gr. 1°35. The action of this acid on uric 
acid must be kept moderate. When crystals of alloxan are formed, 
the whole is thrown on a filter, the throat of which is stopped with 
asbestus. That portion of the acid liquid which remains in the crystals is 
displaced by a few drops of cold water, and the crystals are purified 
by re-crystallization. The liquid is again employed in the same way, 
and the crystals are collected as before. Five such operations may be 
performed with the same liquid, each yielding a large crop of erystals ; 
while the mother liquid is preserved, and yields a large quantity of 
parabanic acid, or oxalurate of ammonia. By this process the author 
obtains from 100 parts of uric acid, 65 of anhydrous alloxan, or 90 of 
alloxan + 6 aq. From alloxan, alloxantine is easily obtained by the 
action of sulphuretted hydrogen. Thionurate of ammonia is easily 
formed, by boiling a solution of alloxan with sulphite of ammonia and 
free ammonia. Uramile is also easily obtained, by boiling a solution 
of thionurate of ammonia with an excess of diluted sulphuric acid. 
Murexide is obtained, as described in another communication by Prof. 
Gregory. He now exhibited the last three processes. He also stated, 
that the theory of the formation of murexide was of great importance 
in reference to organic colouring matters. 
