British Association for the Advancement of Science. 43 
This acid contains the radical of oxalic acid, combined with eya- 
nogen. Ihave attempted to show, in some former researches, that 
carbonic oxide, and not carbon, constitutes the radical of carbonic 
acid, and of oxalic acid, and that phosgene gas might be consid- 
ered as containing the same radical in combination with chlorine. 
If we indicate carbonic oxide by R, these compounds will be as 
follows :— 
1. Phosgene gas R+Cl. 2. Carbonic acid R+0O. 3. Oxalic acid 
2R 
Now, the acid which combines with urea to form uric acid, may 
be expressed by the formula R+Cy. Viewed inthis manner, the 
composition of uric acid will be 4(R+Cy)+Ur. 
Uric acid, when heated with brown hyperoxide of lead, was 
decomposed into three different products, oxalic acid, urea, and a 
peculiar substance, which we may view as a compound of cyano- 
gen and water, and which is identical with a body long known, 
called allantoic acid, from having been first found in the allantoic 
fluid, but which it would be better to call allantoin, as it is capa- 
ble of acting equally as an acid and a base. 
One atom of uric acid, decomposed by the action of two atoms 
of hyperoxide of lead, is converted (supposing three atoms of 
water to be present) into two atoms of oxalate of lead, one atom 
of allantoin, and one atom of urea. 
1 atom uric acid + 2 atoms hyperoxide of lead 
(C NH O)+Pb. O 
104 4 6 2 4 
gives 
(8-0) oxalic acid (+2 Pb. O) oxalate of lead 2 atoms 
2 
(4 Cy +3 Aq.) allainton 
1 atom urea. 
Allantoin is the second body belonging to the animal organiza- 
tion, which we can form artificially in the laboratory. This sub- 
stance can also be directly produced by the decomposition of cy- 
anogen and water. It yields, when decomposed by other bodies, 
all the products which, from its formula, might be expected. 
Thus, with alkalies, it yields oxalic acid and ammonia, with 
strong sulphuric acid, carbonic acid, and carbonic oxide. 
There are many bodies similar to urea and allantoin, all of 
which will probably, at a future period, be produced by artificial 
means ; but, in order to arrive at this, the final object of investi- 
