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Brugnatelli’s, who as early as 1817 obtained from it, by oxidation, 
a crystalline product, which he called “ erythric acid,” Wohler 
and Liebig, by, in a sense following in Brugnatelli’s footsteps, but 
looking with sharper chemical eyes, discovered, instead of one, a whole 
host of derivatives, the disentanglement of which, even to them, must 
have been a tough problem. But they did not rest before each and 
every one of the bodies had given a clear account of itself. 
Liebig, somewhere in his Chemical Letters, spricht ein grosses 
wort gelassen aus, “ of any scientific investigation worthy of the 
name, the main results can be summed up in a few words.” It 
holds for his and Wohler’s case. Uric acid when oxidised behaves 
as if it were potential urea plus potential mesoxalic acid C 3 0 3 . (OII) 2 . 
Part of the urea comes out as such ; the rest unites with the 
mesoxalic acid into a “ureide” with elimination of water, formed 
from the two (HO)’s of the acid and two of the hydrogens in one 
molecule of the urea. This is alloxan (Brugnatelli’s erythric 
acid in a pure state). But alloxan itself, when further oxydised, 
loses part of its carbon as carbonic acid and becomes para- 
banic acid , the ureide of oxalic acid C 2 0 2 (0H) 2 . Either ureide, 
when treated with caustic alkali, takes up first one and then a second 
molecule of water to form, in the first instance, alloxanic and 
oxaluric (hydro-parabanic) acid, in the second, urea plus mesoxalic 
and oxalic acid respectively. Either ureide, when subjected to re- 
ducing agents, takes up one atom of hydrogen per molecule and is 
reduced, the one to alloxantine, the other to oxalantine. A more 
limited oxidation of uric acid leads to the formation of allantoine 
which, before Liebig and Wohler, had been known only as a com- 
ponent of the allantois-liquid of the cow. These few notes do not pre- 
tend to do justice to the great research; but they will suffice to give to 
the general reader a notion of its importance. Liebig and Wohler’s 
work — apart from a few isolated though not inglorious attempts — 
was not continued until Baeyer took it up and rounded it off. 
Baeyer has enabled us to see clearly certain relations which had 
before been obscure ; but it is worthy of notice that, while over- 
hauling the whole of Liebig and Wohler’s work, he found nothing 
to rectify ; it all proved solid masonry on which he was able to 
build without resetting a single stone. 
After their uric acid research the ways of Wohler and Liebig 
